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An investigation into how the obesity epidemic and our environmental woes may be interwoven societal problems.
Just recently a colleague and friend of mine, Travis Saunders, asked me to guest post on his blog: Obesity Panacea - a highly cited obesity blog, hosted by the Public Library of Science Blog Network. The post highlights a portion of my PhD work investigating how change in child weight status relates to local environmental factors. You can access the post here. The papers on which my post focus on can be found below. Carter MA, Dubois L, Tremblay MS, & Taljaard M (2012). The Influence of Place on Weight Gain during Early Childhood: A Population-Based, Longitudinal Study. Journal of urban health : bulletin of the New York Academy of Medicine PMID: 22806452Carter MA, Dubois L, Tremblay MS, Taljaard M, & Jones BL (2012). Trajectories of childhood weight gain: the relative importance of local environment versus individual social and early life factors. PloS one, 7 (10) PMID: 23077545... Read more »
Carter MA, Dubois L, Tremblay MS, & Taljaard M. (2012) The Influence of Place on Weight Gain during Early Childhood: A Population-Based, Longitudinal Study. Journal of urban health : bulletin of the New York Academy of Medicine. PMID: 22806452
Creative Commons imageToday's post is a follow-up to the previous post on the pervasiveness of environmental contaminants and pollutants and the potential link to obesity, particularly in utero. As I left off, much research remains to be conducted to definitively link specific industrial chemicals (known endocrine disruptors), which are highly prevalent in our society, to obesity.The precautionary principal is used to protect public health and has various interpretations. In general, it says that complete evidence of harm does not have to exist before steps can be taken to protect members of society from harm (Weir et al, 2010). In this post, I'd like to discuss a Canadian-specific framework for applying the precautionary principal in relation to suspected obesogens, public health, environmental health, and our overall North American lifestyle. Historically, there has been a general failure in North America and Europe to determine potential negative public health and environmental effects from industrial chemicals before manufacture and widespread use (Wordsworth et al, 2007). This likely explains why every person or animal that has ever been tested has had detectable levels of endocrine-disruptors in their bodies."An analysis by the Environmental Protection Agency in 1998 found that, of the 3,000 chemicals that are used in the highest volumes in the United States (3), forty-three per cent had no testing data at all that would establish their basic toxicity. Only 7 per cent had a full set of safety tests (4). For chemicals used in lower volumes, even less information was available (5)." (Wordsworth et al, 2007).The European Union is no better. And we Canadians don't have a lot to be proud of either:More recently, in September 2006 the Canadian government concluded one of the most extensive reviews of substances ever undertaken. The government identified more than 4,000 suspect chemicals in Canada with the potential to be persistent, bioaccumulative and “inherently toxic” (8)." (Wordsworth et al, 2007).Does this mean that the precautionary principal is not relevant? If the link between certain endocrine-disruptors and obesity is found to be causal, is it already too late? I think it's a no to both, but truly unfortunate to have to put ourselves in this situation in the first place. Applying the principal, particularly when it has to do with the environmental sector and public health, is far from straightforward, as you will see.Weir et al (2010) propose a framework for applying the precautionary principal in Canada (10 Guiding Questions). There are two parts. The first assesses the degree of certainty to which the relationship between a risk (in this case certain chemicals) and harm (obesity and other potential health outcomes) can be considered causal. They use Sir Bradford Hill's 9 criteria for causation. Anybody with an epidemiology background should know what these are. I'm not going to list them here, simply because they're not really necessary for what I am going to talk about. What I am interested about is the second part, the remaining 9 questions, and Weir et al's discussion.2. Is the harm associated with the suspected exposure serious?3. Is the suspected exposure widespread?4. Is there an observed increase in the incidence of the suspected harm that is temporally associated with increased exposure?5. Is the harm associated with the suspected exposure difficult to treat or reverse?6. What are the economic and non-economic costs and benefits of action and non-action?7. Are the proposed control measures proportional to the level of risk? Are the economic costs of removing the exposure minimal? Are the health and societal costs of removing the exposure minimal?8. Are comparable situations being treated similarly according to a standard of practice?9. Is the level of the protective measures consistent with equivalent areas inwhich scientific data are available?10. If precautionary measures are adopted, is there any new evidence to reduce the level of uncertainty about harm and benefit?Going by these questions, yes obesity is serious and yes exposure is widespread. I would say that at this point, #4 can only be answered in animal studies. Obesity has been difficult to treat and reverse and it has multiple determinants. Number 6 and 7 are where it starts to get tricky. Because obesity has multiple determinants (i.e. is complex) and because of lack of evidence, it's hard to say whether decreased use of these chemicals would result in less obesity and related diseases and therefore lower healthcare costs and other indirect costs like absenteeism/presenteeism. Weir et al contend that the appropriateness of applying the precautionary principal increases "when the economic and social costs of removing the exposure are small relative to the suspected harm." These chemicals no doubt make life easier for us - are we willing to give up a certain level of convenience to live without them, at least until adequate replacement substances are found (I have faith in technology to remedy this gap rather quickly)? Are we willing to knowingly gamble with our economy? I could answer for myself, but I'm sure that many others would disagree, some with valid points. At the same time, Weir et al add that appropriateness of applying the principal increases "when the health costs of removing the exposure are minimal; and when, in addition to the uncertain harms, there are known health, economic or social harms caused by the exposure." I can't see health costs associated with removing obesogens; worse case, procedures with medical equipment made with obesogens are no longer possible until replacement substances are found. Obesogens also have known negative impacts on the environment and suspected health impacts that go beyond obesity. I am unaware of comparable situations that could be used to address #8 (that doesn't mean there aren't any), and we're not even close to answering #9 and #10 yet. This is only the tip of the iceberg. Based on this quick run-through, I hope you grasp the complexity of this problem. What do you think? Is it too late to apply the precautionary principal? Is applying the principal even relevant for obesity, or worth the potential negative social and economic effects? Is not applying it worth further environmental damage? ... Read more »
Weir E, Schabas R, Wilson K, & Mackie C. (2010) A Canadian framework for applying the precautionary principle to public health issues. Canadian journal of public health. Revue canadienne de sante publique, 101(5), 396-8. PMID: 21214055
Everybody knows that obesity results from energy in being greater than energy out, right? Okay, we know that it's a lot more complex than that, but what if obesity could arise separate from this? We're pretty wedded to the idea that diet and physical activity are major risk factors, so it may be a little disconcerting to learn that a new body of research suggests that being exposed to "obesogens," chemicals in the environment (usually man-made), may program us to be fat. In this first post, I will provide a very basic overview of obesogens, leaning heavily on two reports. In the second post of this two-part series, I will discuss what this means in terms of the precautionary principal versus level of evidence.CBC (the Canadian Broadcasting Company) aired a documentary earlier this year that discussed the puzzling results of scientists researching endocrine-disrupting chemicals. Their original projects were not about fat, but their lab animals turned out to be unusually heavy after being exposed to these chemicals. The documentary can be accessed here. You can have a sneak-peek by viewing the trailer below.We know that fat tissue acts like an endocrine organ. Since endocrine-disrupting chemicals include a wide variety of substances it is difficult to generalize mechanisms of actions. The Endocrine Society gives the following broad definition (Diamanti-Kandarakis et al, 2009):"An endocrine-disrupting substance is a compound, either natural or synthetic, which through environmental or inappropriate developmental exposures alters the hormonal and homeostatic systems that enable the organism to communicate with and respond to its environment." In general though, it is thought that obesogens mimic hormones, which can increase the size of fat cells, increase the number of fat cells or negatively affect appetite, metabolism, and/or food preferences (Holtcamp, 2012). Much of the evidence to date has been from animal studies, but there are many epidemiological studies linking exposures of 15-20 chemicals during fetal and infant development to infant and child weight status (Holtcamp, 2012). Take for instance, smoking during pregnancy - there is fairly persuasive epidemiological evidence linking this to obesity in children (Oken et al, 2008). There is also some evidence for an effect of endocrine-disrupting chemicals on adult weight status; however this is a burgeoning area of research that is need of more studies (Tang-Péronard et al, 2011). Obesogens (those in addition to the byproducts of smoking) are found everywhere - in industrial solvents/s and their byproducts (e.g. PCBs), plastics, plasticizers (phthalates), pesticides, pharmaceutical agents (Diamanti-Kandarakis et al, 2009)(Holtcamp, 2012). We are exposed to these chemicals by drinking contaminated water, eating contaminated food, breathing contaminated air, or coming into contact with contaminated soil. In industrial areas, chemicals can leach into the soil and contaminate the ground water, and may bio accumulate in both humans and animals. The web of contamination is so complex that areas considered "prestine"and remote from the original site that produced the chemical, have been found with levels of the chemical (Diamanti-Kandarakis et al, 2009). Many of these obesogens are also found in items we may or may not use every day. Examples include: medical devices, some canned foods, cash register receipts, designer handbags, items made of Gore-tex(TM), wallpaper, vinyl blinds, tile, and vacuum cleaner dust, air fresheners, laundry products, personal care products, items with Scotchgard(TM) (e.g. carpets, furniture, and mattresses), non-stick cook-ware, and microwaveable food items. There are also potential dietary obesogens including phytoestrogens (soy) (Diamanti-Kandarakis et al, 2009) and MSG (monosodium glutamate) (Holtcamp, 2012). Many endocrine-disruptors demonstrate an inverted U-shaped dose-response association. This means that with medium "doses" of the chemical, obesity risk increases. But at low and high doses, the risk decreases. This likely depends on the chemical and other factors as some endocrine-disruptors have been found to increase risk at very low or very high levels. Estimating the level of exposure that leads to a negative... Read more »
Microsoft Office ImageMany writers (e.g. Mark Bittman), journalists, researchers, scientists, and celebrity chefs (e.g Jamie Oliver), believe that if people cooked more, obesity wouldn't be such a big issue. While I agree with this observation generally and feel that it could probably be good for the environment too, I don't think it is something that on its own could ever be effective in our capitalist society.First, how can cooking our own meals help the obesity epidemic? Meals and snacks eaten outside of the home generally have more calories than those made in the home. Simplistically, if you consume more calories than you expend on a regular basis, you're going to gain weight. There is also some evidence that eating more frequently outside of the home is related to an increased body weight. Preparing your own meals also cuts down on packaging, particularly if you eat a lot of fast food, which is better for the environment. And preparing your own meals means just that - as Yoni Freedhoff recently commented, nuking something doesn't count.Cooking is a skill. It requires time. I've frequently heard that cooking skills have been on the decline (although I can't give a you specific source for that). I'd guess, because they're not necessary anymore (abundance of prepared, tasty food), and perhaps due in part (please feminists don't hate me) to the emergence of the two-working-parent family; the housewife social norm is disappearing. People, therefore, need to be taught how to cook; and to cook food that tastes at least as good as what could be bought pre-made. Where and how would this happen? Sure,we can get at kids in schools, but what about their parents? Adults are a less captive audience. Second, people don't feel like they have time. They're stressed. Everyone is. But, this is particularly tough for people on lower incomes, trying to make ends meet. They know the value of healthy eating but lack time and resources. Thus, sometimes being able to get prepared foods for relatively cheap is valued much more highly than cooking skills and being able to cook one's own meals. Some people can't even afford places to live that have enough room for cooking equipment anyway. Given the current state of global economic affairs, I imagine, that these scenarios will only become more frequent. If we want to people to cook more, it's not simply a matter of setting up social marketing campaigns and saying "hey you guys, you should cook more." There needs to be education programs in schools, the workplace, and the community, as well as changes in policies to support those trying to get by (minimum living supplement, housing and energy subsidies, etc.), workplace policies that are family friendly, egalitarian, and aim to reduce stress, etc. To his credit, I believe Bittman does allude to these nuances in his new book. So these are the first prerequisites (or 'upstream' factors) for being able to cook more in our society.Second, social norms need to change. Bittman and others have also suggested this - that valuing cooking and eating needs to become the societal norm. In North America, I'd say we value eating. We can get incredibly good tasting food pretty much anywhere, but we eat it 'on the run'. What we don't value anymore is appreciating the food, and the social aspects of eating - that social interaction when cooking and eating with family/friends. Changing this norm runs hand in hand with the incredible convenience of our society; being exposed to such an abundance of food that's ready made for us. I find it mind boggling the amount of 'stuff', not even just food, that is available for consumption. Take Walmart for example. Everything is convenient and available to us at very little cost. I'm not even sure that we knowingly value the convenience of having someone else prepare our meals - it's just something that we take for granted - it just is. Cooking is an effort and if we don't feel like doing it, we know we can get prepared food easily elsewhere. I didn't feel like cooking the other day, so opted to get sushi take-out instead. That took all of 5 min. And I do it more than I care to admit...I doubt that in a capitalist society like ours, decreasing the number of products out there for consumption is a viable option. I don't think that taking away convenience would work either (aside from some sort of environmental or man-made catastrophe). So, if both stay, there is really no incentive to cook. Sure, some efforts may have some sort of impact. But the reality is that we have pre-made food all around us, all the time. Plus, we'd need to have the prerequisites in place that I talked about above. This may be difficult given that many in society do not value collectivism, and oppose government intervention (read: the 'nanny' state). What could work in the mean time? I don't mean to say here that people should not cook - because I'm not saying that. We need to cook more, absolutely, but I'm skeptical about it having an impact on the obesity epidemic. Prepared food needs to change (e.g. fast food meals, pre-made meals in grocery stores). It needs to become healthier, with smaller portion sizes. Meals need to have more veggies and legumes; there needs to be more options with less meat. Prepared food needs to have taste that rivals its unhealthy competitors (with less salt); and it needs to preserve the convenience factor to be competitive. Packaging should also be biodegradable and we should use less of it. We should also strive to produce food locally, mostly to support local farmers, but also for other reasons that might be debated (read: environmental). Marketing of these healthier foods needs to be creative to maximize dollars spent, as for example, McDonald's marketing budget exceeds many countries' GDP.I'm drawn to Portland, Oregon as an example of what could happen elsewhere in North America, to rival the dominant fast food chains and pre-made meals sold in grocery stores. Portland is considered a world-class city for street food. City policies allow local vendors to set up shop on semi permanent pods in private parking lots. Food is cheap, and there are over 700 food carts; therefore, lots of variety to chose from. Street food vendors are popular with the workers at lunchtime, tourists, and the after bar crowd. Food carts also promote sustainability and walkability, but in many cities, zoning and public health policies limit their proliferation. Vancouver is moving slowly to allow more street vendors to operate within its borders. In Ottawa, it's non-existent, save for examples like the Stone Soup Foodworks Truck, a mobile food vendor selling soups, sandwiches, salads, and tacos made from local, organic producers. Throughout most of the school year this truck can be found on the campus of the University of Ottawa, but it also frequents events throughout the city. There has been an attempt by the broader community in Ottawa to try and start a street food movement - but it doesn't look to have gained enough steam at this point to provide much sway to city officials.... Read more »
Lachat, C., Nago, E., Verstraeten, R., Roberfroid, D., Van Camp, J., & Kolsteren, P. (2012) Eating out of home and its association with dietary intake: a systematic review of the evidence. Obesity Reviews, 13(4), 329-346. DOI: 10.1111/j.1467-789X.2011.00953.x
Bezerra, I., Curioni, C., & Sichieri, R. (2012) Association between eating out of home and body weight. Nutrition Reviews, 70(2), 65-79. DOI: 10.1111/j.1753-4887.2011.00459.x
Troy LM, Miller EA, & Olson S. (2011) Hunger and Obesity: Understanding a Food Insecurity Paradigm: Workshop Summary. Institute of Medicine. info:/
It’s pretty hard to determine if residential characteristics influence the development of obesity. There are a multitude of reasons for this, but one I want to focus on is the research design of the study. Most research in this area has been cross-sectional (looking at one point in time only). The problem with these studies is that we have no idea what came first, the neighborhood characteristic or obesity. There is also the issue of self-selection. Certain people may prefer to live in certain types of neighborhoods for a variety of reasons that may be related to weight; thus it’s not the neighbourhood characteristic(s) per se that explains the association with weight status, it’s something else that we haven’t measured. Longitudinal studies are better but tend to be based on cohort studies where the main intent was not to examine neighbourhood level effects. This means that the researcher has to use whatever information has been collected, and usually this gives an incomplete picture. Plus, there’s the attrition issue. People get fed up after a while, and some drop out of the study. This decreases power to detect significant differences and can introduce bias if dropout is in some way related to the outcome. So, imagine my surprise when I learned about a randomized social experiment with obesity as the outcome. Randomization balances the exposure [neighbourhood characteristic(s)] on known and unknown confounders, and rectifies the issue of temporality. Randomized controlled trials are the gold-standard in clinical epidemiology, but for ethical and economic reasons, are usually not feasible in social epidemiology (randomizing people to smoke, for instance, would never fly). The study, published by Jens Ludwig and crew in the New England Journal of Medicine, was based on the Moving to Opportunity for Fair Housing Program, conducted by the US Department of Housing and Urban Development (HUD). The basic premise of this experiment was to determine how best to provide housing for those in need. Briefly, 4498 families with children living in public/project housing in high poverty neighbourhoods in Baltimore, Boston, Chicago, Los Angeles, or New York, were randomly allocated to one of three groups in the years 1994-1998 (one quarter of those eligible): 1. The MTO low poverty voucher group which received rental vouchers usable only in low-poverty areas (where Significant differences were for severe obesity, not for overweight or obesity in general. = No baseline data was available for BMI or glycated hemoglobin so changes could not be assessed (the authors state that this shoul... Read more »
Ludwig J, Sanbonmatsu L, Gennetian L, Adam E, Duncan GJ, Katz LF, Kessler RC, Kling JR, Lindau ST, Whitaker RC.... (2011) Neighborhoods, obesity, and diabetes--a randomized social experiment. The New England journal of medicine, 365(16), 1509-19. PMID: 22010917
CC Image: Franco Folini Now I am not generally one to give money to a pan-handler. If I do give something, it’s generally a snack (usually healthy) if I have one on me. This has been met with different responses: scorn, indifference or thankfulness. I have offered a few times to go and buy these pan-handlers something to eat or drink but have never been take up on the offer, until today. I regret though, that I may have contributed to, not helped the problem of food insecurity. I had stopped off to the side of the sidewalk to grab something from my purse when I was confronted by a shabbily dressed, young man. I had walked to an appointment along Dalhousie Street in Ottawa (for those of you who know where that is) and was on my way back to work. Since I was stopped, kneeling over my bag, I was a captive audience for this particular individual. He proceeded to tell me all of his problems, from being kicked out of the shelter down the street because of a fist fight, to not having enough to eat. He also assured me that spending money on drugs was not an issue because he doesn’t use them. I was waiting for him to ask me if I could give him money, but that didn’t seem to surface from the avalanche of words spewing from his mouth. I interjected, “can I buy you something to eat?” He replied with “oh yes, yes, please, I’m so hungry.” At this point I should maybe provide a little background on food insecurity. The prevailing definition of food security is “a situation that exists when all people, at all times, have physical, social, and economic access to sufficient, safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life.” Food security and insecurity are on opposite ends of a continuum. Food insecurity has different stages of severity starting with not being able to buy and eat what one would like. This gets at issues of quality including variety, safety, nutrient content, and the caveat that foods must last and not go to waste. The next stage involves a decrease in quantity which might or might not be accompanied by hunger. Finally, the most severe stage is the complete absence of food intake (going completely without). Food security is a basic human right, but from the 2007-2008 Canadian Community Health Survey, 7.7% (961,000) of Canadian households were food insecure. And keep in mind this is for people with a fixed address, unlike homeless people and those in shelters, so it is likely higher. I imagine this figure will only climb as our (Canadian) income gap rises and worldwide economic problems deepen; unless of course, our social policies change, but that’s a discussion for another day. Remember that a key part of food security covers quality – we should have access to healthy, nutritious food. Being food insecure is related to decreased quality of foods consumed and nutrient inadequacies, which makes intuitive sense. I regret that although I was providing food in principle, it was not of the nutritious variety. We went to the nearest restaurant, Garlic Corner, and I said to the guy “get what you like, I’ll pay for it.” He hummed and hawed, something about wanting breakfast down the street because “these guys don’t serve it past noon, and they are really, really slow.” Then it was he didn’t eat meat but didn’t want any of the vegetarian options. Either the choices at Garlic corner were not healthy enough (which is partially true) or he wanted money instead, of which I am guessing the latter. Anyway, he settled on a Nanaimo cake thing and a red bull. All crap. I mulled all of this over on the remaining walk back to the office. What have I done here? Propagated the problem? Should have I stipulated what he order, ordered it for him, went to a better restaurant, what? What do you think? I tried to help out a fellow human in need, but did I really? Even if I had stipulated what he had ordered, it would have been denigrating. The other alternative is to ignore street people. While I have done this in the past, I am growing increasingly uncomfortable with it, trying now to at least acknowledge them as people when I walk by – a smile, node, or hello. I don’t mind providing a snack here and there but I’d almost rather do nothing if it means that another red bull or Nanaimo cake gets sold and consumed. Pilgrim A, Barker M, Jackson A, Ntani G, Crozier S, Inskip H, Godfrey K, Cooper C, Robinson S, & SWS Study Group (2011). Does living in a food insecure household impact on the diets and body composition of young children? Findings from the Southampton Women's Survey Journal of Epidemiology and Community Health, June 7 : 10.1136/jech.2010.125476Kirkpatrick SI, & Tarasuk V (2008). Food insecurity is associated with nutrient inadequacies among Canadian adults and adolescents. The Journal of nutrition, 138 (3), 604-12 PMID: 18287374... Read more »
Pilgrim A, Barker M, Jackson A, Ntani G, Crozier S, Inskip H, Godfrey K, Cooper C, Robinson S, & SWS Study Group. (2011) Does living in a food insecure household impact on the diets and body composition of young children? Findings from the Southampton Women's Survey. Journal of Epidemiology and Community Health. info:/10.1136/jech.2010.125476
Kirkpatrick SI, & Tarasuk V. (2008) Food insecurity is associated with nutrient inadequacies among Canadian adults and adolescents. The Journal of nutrition, 138(3), 604-12. PMID: 18287374
Urban planning and epidemiology need to become better friends. Rigorous epidemiological studies that assess the health impacts of urban planning interventions are desperately needed. These studies can more reliably tell us what works and what doesn’t, and therefore where best to put our hard-earned tax dollars. I’m not sure why they are lacking. Money? Time? I guess they are all good excuses. But in the grand scheme of things, I would settle for even just a simple before-after study – something that I think is more than feasible.Ottawa recently implemented a segregated bike lane pilot project on Laurier Street, running from Bronson to Elgin Streets. The lanes are blocked off from traffic with concrete curbs, plastic poles, parked cars and planter boxes. New road markings (including those gross green boxes) and signs tell cyclists where they should be. Most on-street parking has been removed and some bylaws have even changed, such as no right turns on a red light, which protect cyclists from absent-minded motorists. The project is part of the City of Ottawa’s plan to become a greener and more sustainable city. All of this is great news for cyclists (and environmentalists), even though it has received some grumblings from residents and merchants on Laurier Street who have lost parking spots as a result. Since the lanes were open on July 10, 2011, almost 117,000 people have used them (that is, passed a counter at Laurier and Metcalf). Wow, that sounds like a lot of people…but wait a sec…How many cyclists used Laurier before? Maybe the same number of people used Laurier last year from July 10th to September 28th, 2010. So this number really tells us nothing. We have no idea what the ‘success’ of the pilot project is defined as either. Is it a certain percentage increase in the number of users, fewer accidents, more commerce, increase in physical activity, etc.? The main points I am trying to make here are that the city could have at least placed a counter in the same location BEFORE they implemented the project, as well as determined significant outcomes a priori and communicated those to the public. I don’t think it would have been that much more costly. I’d like to highlight that this would be something that is needed in the very least. These types of designs that use counters to count the number of users before and after are not robust against bias and cannot capture all that we would really like to examine. Here are a few examples why: We can only count users and not individuals so likely we are double, triple counting, etc. Perhaps increase in usage is only by those people that already cycle on the road If counters are electronic, I'm not sure if they can discriminate between cyclists and people that shouldn't be using the lane (such as skateboarders, motorized scooters, etc.)We cannot determine impact on the health outcomes of individuals living nearby, such as increased physical activity or decreased obesityIncrease/decrease of cycling on Laurier could actually be due to other factors that we have not accounted for or reflect only secular trends (not due to the new lane)I have had a very hard time finding an urban planning intervention with the intent of increasing active transportation/physical activity, or decreasing obesity, that has been well conducted. There is also the added caveat of residents actually knowing about the change to their environment. For example, if they don’t know about a new bike lane, trail system, or park how can they use them? A study by Evenson et al (2005) perhaps is a basic model to follow– with, of course, some upgrades (e.g. addition of a control group). They set out to determine if a new rail trail built in Durham North Carolina (US) significantly increased time spent in leisure activity, moderate and vigorous physical activity, and active transportation of residents living nearby. Participants 18 years or older living within 2 miles of the trail were randomly recruited to participate in two telephone surveys conducted before and after introduction of the trail (n = 366). Questions were largely based on the Centers for Disease Control and Prevention’s Behavioural Risk Factor Surveillance System. The researchers did not find that the new trail had any effect on the outcomes they looked at. There were some issues with the study which may explain why they did not find anything. Some examples include: The after measurement occurred just 2 months after the trail opened – this may not have been a sufficient amount of time (e.g. residents may still not have known about it). In fact, 38% of respondents said they weren’t aware of the trailThe after measurements occurred in November, whereas the before measurements occurred in summer and early fall. In Canada at least, we tend to be outside less as the winter approaches versus in the summerLow response and retention rates. The people who responded were likely not representative of the population (they already had high baseline rates of activity). What were the people who didn’t respond like?... Read more »
Evenson, K., Herring, A., & Huston, S. (2005) Evaluating change in physical activity with the building of a multi-use trail. American Journal of Preventive Medicine, 28(2), 177-185. DOI: 10.1016/j.amepre.2004.10.020
Eating that double-fudge brownie or entire bag of chips ultimately comes down to individual choice. However, it is becoming more and more apparent that we are not really free to choose – our choices arise from opportunities or barriers that are structured in large part by the places in which we live, work, play, or go to school. The abundance of ultra-processed, energy –dense, nutrient-poor foods that are readily available, heavily marketed, cheap, and tasty, presents a large barrier to many of us in terms of following a healthy diet. How can we counteract this to make healthier foods like fruits and vegetables the more attractive option? I’ve been thinking about this a lot lately, wondering if the only way is to make these foods just as convenient to consume, such as in healthy prepackaged meals, and somehow find the means to heavily market them in the same way as Big Food.Behavioral economics may be a simpler way – changing the layout of cafeterias, stores, and restaurants to subtly influence people to make the healthy decision. Smarter lunchrooms is an initiative out of the Behavioral Economics and Nutrition Center at Cornell University concerned with doing exactly this. Their philosophy is that draconian school food policies, like banning junk food from cafeterias, don’t work. Often children will skip lunch, bring in their own snacks, or head to a fast food restaurant. Principal investigators Brian Wansink and David Just think that ‘nudging students toward making better choices on their own, by changing the way their options are presented’ is a better option. I tend to agree.Although the epidemiologic evidence doesn’t look like it’s strong (most studies appear to be case studies or before-after and I’m not entirely sure of the methodology), I think the results of some of these interventions are worth discussing, especially since most of these are low cost and low effort for the school to implement. Hopefully some larger scale, well designed randomized controlled trials are on the horizon (us epidemiologists can only dream). Here are a few examples from Wansink & Just, as well as their colleagues (virtually verbatim from their website):Putting nutritious foods like broccoli at the start of the cafeteria line, rather than in the middle, increased sales by 10-15% Switching apples and oranges from a stainless steel pan to a fruit bowl more than doubled fruit salesGiving healthy food choices more descriptive names like ‘creamy corn’ rather than ‘corn’ increased sales by 27% Moving the chocolate milk behind the plain milk led students to buy more plain milk Putting the salad bar in front of the check-out register nearly tripled sales of saladsWhen cafeteria staff asked students if they wanted a salad, salad sales increased by a third Requiring that desserts such as cookies be paid for in cash (not with lunch tickets or debit cards) led students to buy 71% more fruit and 55% fewer desserts Keeping ice cream in a freezer with a closed, opaque lid significantly reduced ice cream sales I think that something like this could in some way be translated to other shared dining spaces such as cafeterias in workplaces, hospitals, and universities, to name a few. Google has actually shown us that it is feasible. Now whether its employees are healthier for it, I'm not sure if it has, or will ever be formally evaluated. Too bad..Seems like a waste of a good intervention study. Just D.R.,, & Wansink B (2009). Smarter Lunchrooms: Using Behavioral Economics to Improve Meal Selection Choices:The Magazine of Food, Farm, and Resource Issues, 24 (3)... Read more »
Just D.R.,, & Wansink B,. (2009) Smarter Lunchrooms: Using Behavioral Economics to Improve Meal Selection. Choices:The Magazine of Food, Farm, and Resource Issues, 24(3). info:/
I am re-posting a guest-post that I wrote in June for my friend and colleague, Travis Saunders, on his blog: 'Obesity Panacea'. I was too lazy then to put the whole thing up on my own blog...Alas, I've come back to it as potential thesis material, so have decided to take the two minutes to format it. You can also view the original post here. I am hoping that researchers and the public at large are starting to get past the ‘blame the victim’ perspective of obesity. True, choice and preference obviously have something to do with it, but we as individuals live and interact in complex environments. Behaviours like sedentarism and eating junk food may be natural responses to opportunities and barriers that are structured by the places in which we live, work, play, or go to school. And not everyone is likely to be equally affected - protected or prone depending on things such as genes, age, sex, socioeconomic status, cultural upbringing, and the like. We need to consider the context in which people live their lives. If not, obesity prevention and treatment efforts are akin to throwing people back into the fire.Humans, by nature, are social animals, so one such contextual factor that has garnered a lot of attention in the field of place and health is social capital. It refers to networks of social relationships that people have and the associated norms of <warranted> trust and reciprocity (gift giving with the expectation of receiving) (1). Social capital can work at the individual level, but also through collective or group-level mechanisms (2). These group-level workings may be most relevant for the development of obesity, since buying and eating food , as well as being physically active, often (but obviously not always) take place in shared spaces, such as neighbourhoods. There is already a vast literature demonstrating an association between low collective social capital and adverse health outcomes such as delayed child development, child and adolescent behaviour problems, stress and isolation, violent crime, and increased mortality (3). A newer body of research is emerging now, suggesting that low collective social capital may be related to obesity and even related diseases such as hypertension (4). Social capital in a collective or community context is often referred to as ‘collective efficacy,’ which is used to describe a number of social processes that may affect health (5). In short, it is the social cohesion (connectedness/togetherness) among neighbours (or members of a community) combined with their willingness to intervene on behalf of the common good.Okay, so how can that translate into obesity? I’ll try to spare you the jargon as much as I can while still conveying the meaning of these pathways (one of the main criticisms of this area of research is that words and phrases describing concepts, and the meaning of these concepts are not consistently applied). Also, keep in mind that these pathways can interact and overlap.
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Informal social controlNeighbourhoods that are more cohesive informally enforce social norms (e.g. obeying the law), which may decrease anti-social behaviours such as graffiti, vandalism, illegal dumping, drug-dealing, violence etc (5). By informally it is meant that residents are willing to intervene when they see someone breaking social ‘rules’. This can have an impact on the physical aspect of neighbourhoods, making them more or less aesthetic, as well as on the perception of safety (6, 7). Both may influence resident’s decisions to be active outside (or decisions to let their kids be active outside), as well as decisions by certain groups of people and organizations to move into or out of the neighbourhood (8). For example, a specialized grocery store relocates out of the neighbourhood to a ‘better’ or ‘safer’ location. Neighbourhood residents therefore, no longer have access ... Read more »
Szreter, S. (2004) Health by association? Social capital, social theory, and the political economy of public health. International Journal of Epidemiology, 33(4), 650-667. DOI: 10.1093/ije/dyh013
Hopefully I will be back to a more or less regular blog posting schedule now that I am back from my trip overseas. I went to Dublin (Ireland) and Edinburgh (Scotland) for a few weeks of vacation and a couple days of conferencing. I was lucky enough to get to do some biking both inside and outside of the city (the city being Edinburgh). Today’s post is more of a reflection on biking culture and infrastructure in Ireland and Scotland versus here in Canada. I was only there for a short while so I am sure locals will have much more insight than I; don’t be afraid to let me know if I’ve got something wrong.Both Dublin and Edinburgh appear to make extensive use of on-street bike lanes. These are generally shared with bus lanes and are often painted red, which makes them impossible to miss by motorists. I noticed continuity of markings and signage (i.e. I as a cyclist knew where I was supposed to be at most times) and priority for cyclists (e.g. areas allocated for cyclists in front of motorists at intersections – see picture below). Bike lanes also continued on more rural roads, along with pedestrian islands to slow traffic, which you don’t see here in Canada. Even though streets were busy and I had to ride on the opposite side of the road I did not feel scared to be on the road, perhaps because motorists are more cyclist-savvy and no one yells or honks at you.
On-street marked bike lanes in Dublin, Ireland
The infrastructure in these cities has made me wonder if on-street marked bike lanes are the way to go. Don’t get me wrong, I am not against segregated lanes, but on-street marked lanes would likely be cheaper, more direct, and make fewer people angry (e.g. merchants who lose parking spaces). Changing our cycling culture requires, at the very least, making friends not enemies (I'll talk about this in an upcoming post). I’m just not sure if on-street marked lanes are safer for the average person and I doubt that parents would be more willing to let their children commute anywhere on them versus segregated lanes or a sidewalk. At the same time, some segregated bike lanes can be dangerous because motorists can’t see you. For example, in Hull, there is a National Capital Commission off-road pathway that crosses three roundabouts; it is blocked to traffic by a wall until you have to cross each roundabout. Motorists coming into and out of the roundabout are looking for other cars and often nothing else. Cyclists are quicker than pedestrians and may appear out of nowhere to motorists. I have had a few close calls. Being on the street makes you seen and forces motorists to more or less treat you like a car. This is why I cycle on the road in this area, even with motorists motioning to me in some sort of code that I think means I should be using the ‘perfectly good bike lane’ beside me.I think therefore that a comparison of segregated and on-street marked bike lane safety is beside the point (the evidence shows that both may be beneficial compared to unmodified road ways, and that the sidewalk is the worst). I guess the appeal of segregated lanes is that they may induce feelings of safety, whether real or imagined which could motivate people to actively commute. My point is that we may want to investigate more wide-spread use of on-street marked bike lanes that are highly visible as in Dublin and Edinburgh, and/or with buffer zones as in New York City (see picture below), as these could improve both real and imagined safety in the same way, improve route directness, be more cost-effective, and piss fewer people off. A buffer zone in NYCReynolds, C., Harris, M., Teschke, K., Cripton, P., & Winters, M. (2009). The impact of transportation infrastructure on bicycling injuries and crashes: a review of the literature Environmental Health, 8 (1) DOI: 10.1186/1476-069X-8-47... Read more »
Reynolds, C., Harris, M., Teschke, K., Cripton, P., & Winters, M. (2009) The impact of transportation infrastructure on bicycling injuries and crashes: a review of the literature. Environmental Health, 8(1), 47. DOI: 10.1186/1476-069X-8-47
One potential way to combat the obesity epidemic and environmental degradation all in the same go is urban agriculture. I’ve been thinking a lot about this lately, wondering if it is feasible in climates like New York City and Toronto, if it can actually generate enough food to continuously feed a city, and of course, also improve diet quality at a population-level.Urban agriculture refers to agricultural practices (usually intensive) within and around cities that compete for resources such as land, water, energy, and labour – but produce food, plant and animal-based pharmaceuticals, fibre, and fuel that benefit the local population (crops and animal husbandry included). This can occur at the micro and meso scales of cities – e.g. using vacant lots, backyards, street verges, green roofs and walls, balconies, community gardens, urban parks, and individual collective garden allotments. Larger scale practices can include commercial farms, nurseries, and greenhouses, which would likely operate in peri-urban areas and be private/corporate, for-profit entities.There are a number of other potential benefits for UA, aside from food, food security, and pollution/land degradation that I hadn’t initially thought about. These include: Employment and incomePersonal skill developmentSocial interaction/community or social capital-buildingIncreased well-beingHighest productive use of land (with respect to vacant lots)Diversified industry baseLight, odour, and noise abatement/absorption I was surprised to read in a recent journal article that in developed countries like Australia, UA is responsible for 15% of state vegetable and fruit production. And that in Sydney, UA accounts for 1% of land area but contributes $1 billion in agriculture produce. Those are interesting numbers, but I still feel skeptical; this is Australia after all, where temperatures rarely fall below freezing. And I imagine that most of this occurs at the macro, not the micro or meso scales. Most research on UA in terms of any type of outcome, not just health (e.g. environmental, social, and economic) has been in the form of case studies, with no real quantification of its benefits. It is difficult to build an argument for this practice with no hard evidence. At the same time, it has the potential to positively affect many different aspects of society, not just health. For this reason, I think UA is worthwhile.I don’t, on the other hand, believe that farming at the micro and meso scales of cities (involving individuals and communities), especially in northern North America, can continuously feed local residents. Farming is time-intensive, and requires certain knowledge and skills. And to feed families year-round in North America, would require up-front investment for equipment like greenhouses. This is not compatible in a culture that breeds convenience and instant gratification, where for example, we don’t seem to have enough time to clean out reusable containers for our drinks, so instead buy crates of water bottled in plastic that can be thrown out or recycled. This may be different if UA at the micro/meso level is a social business, or a private/corporate entity. An example is the Science Barge in New York City, a 1300-square-foot greenhouse that floats on the Hudson River. It is a sustainable urban farm powered by solar, wind, and biofuel and irrigated by rainwater and purified river water. Fresh fruits and vegetables are grown using recirculating hydroponics and aquaponics. And surprisingly, despite floating on the river, is a prototype for a sustainable roof-top garden (more information on the Science Barge can be found here). Another example is Gotham Greens, a roof-top greenhouse in Brooklyn, NY that grows vegetables and herbs for local restaurants and retailers using sustainable methods. They expect to produce 80 tons of produce yearly, and employ residents in nearby communities. Gotham Greens greenhousesMacro-level UA in urban fringes using sustainable methods has potential, but right now is often more costly or harder to access than buying produce at supermarkets like Loblaws or Metro. Government policies (e.g. zoning) and community initiatives that support local farms will be needed to make buying local... Read more »
Pearson, L., Pearson, L., & Pearson, C. (2010) Sustainable urban agriculture: stocktake and opportunities. International Journal of Agricultural Sustainability, 8(1), 7-19. DOI: 10.3763/ijas.2009.0468
There is no disputing that diet and physical inactivity are contributors to the obesity epidemic. A recent debate involving Drs Yoni Freedhoff and Bob Ross showed that both are important (I don’t think there was consensus in the audience as to who won). What I want to highlight in this post is that, from a sustainability perspective (see my previous post for a definition), it is a moot point to argue over the relative importance of each.Our food system has changed dramatically over the last few decades. We can get tasty, energy dense, often nutrient-poor foods anywhere, for very little money. And we’re constantly bombarded with advertisements to buy and eat these foods. What’s more is that we have almost completely engineered physical activity out of our daily life. For instance, most jobs nowadays require sitting for 8 hours (I am sitting as I write this), escalators and elevators do the climbing for us and are easily accessible, and we live far from where we work, play, or go to school so often must rely on the car, which involves more sitting.I think there is a consensus developing among obesity researchers and health professionals that obesity (or diabetes or other related diseases) is not entirely the fault of the individual. In my opinion, unhealthy behaviours are a natural response to our “obesogenic” environment, which increase a person’s risk of developing obesity. So then why do we expect that prevention or treatment efforts targeted at the individual will be effective and maintained over the long-term? To fix our deranged food system and culture of sitting requires interventions at higher levels of social organization, including changes stemming from the local community, municipal, provincial, and national governments, as well as the global community.In the last 10 years there has been a boom the number of scientific studies examining how our environments, beyond the household, are associated with obesity. The majority of these studies have been observational, with a cross-sectional design, and have looked at things like how street infrastructure, fast food restaurant density, and socioeconomic-level of residential neighbourhoods relate to obesity among adults. Children have been less studied in this regard, as well as other types of environmental exposures, such as social interactions, and other types of areas, such as those around workplaces and schools (since these are likely not in one's residential neighbourhood). Perhaps because of the complexity involved, even fewer studies have examined how specific policies and programs may influence physical activity, diet, and obesity at higher levels of social organization (you can find an example here). Certainly more studies are needed given the weaknesses in the current literature, as well as the dearth of information in some areas. But I would like to put forward another argument. Increasing the “walkability” and “liveability” of our shared spaces - *may* decrease obesity but will likely help to decrease green house gas emissions. Making it easier for us to get and cook wholesome foods (namely fruits and veggies) that are free of pesticides, antibiotics, and other chemicals, and harder to get meat, as well as processed foods *could* decrease obesity, but could also help to reduce land degradation, pollution of our water sources, and climate change. All of these things are good for our health in ways other than on our waistline. My argument is that if there is a focus on sustainability, which these changes imply, population and environmental health should follow. We need to focus on BOTH the diet and physical activity side in order to not only combat obesity, but a myriad of environmental problems and related health ailments like diabetes and asthma. These changes are complex, don’t happen overnight, and may bring with them a whole set of new problems (the potential problem of denser living leading to a decrease in indoor air quality immediately comes to mind as an example). Nonetheless, I think we need to move towards rigorously implementing and evaluating interventions that increase sustainability – looking to see if they a) improve the environment, b) reduce obesity, or improve lifestyle behaviours, and c) that they do not negatively impact health in other ways (a post for another day). ... Read more »
Feng J, Glass TA, Curriero FC, Stewart WF, & Schwartz BS. (2010) The built environment and obesity: a systematic review of the epidemiologic evidence. Health , 16(2), 175-90. PMID: 19880341
Today’s post focuses on why you should eat yer fruits and vegetables, and how we may be able to get more of us to do so. At a population level, the evidence for increasing fruit and vegetable (F&V) consumption and decreasing obesity isn’t super strong . But I still think that it’s at the heart of how to make a healthy population – coupled of course, with decreasing intake of crappy, energy dense, nutrient poor snack foods and sugar-sweetened beverages, as well as growing food in sustainable ways (e.g. sans pesticides). For instance, insufficient intake of F&Vs is estimated to cause around 14% of gastrointestinal cancer deaths, about 11% of ischemic heart disease deaths and about 9% of stroke deaths worldwide . They may even be able to make our immune systems healthier and decrease common communicable diseases . Fruits and vegetables have seemingly magical properties – they are abundant in vitamins and trace minerals, often are high in fibre, and are low in calories. But we don’t get enough of them – even in developed countries. Just to give you an idea, in 2004, only 30% of Canadian children (aged 4- 8 y) and 50% of adults met dietary recommendations for F&V intake . More concerning is that children aged 4-18 years obtained a higher percentage of their calories (22.3%) from foods that are not recommended in the Canadian Food Guide (food high in sugar, fat and salt and low in nutrients) than from F&Vs (13.9%) . How can we increase intake? I think it’s all about making F&Vs easier to buy and prepare. This means that they are easily accessible, cheap, and offered in healthy, ready-to-eat meals (not only as whole foods). Grocery stores have been identified as potential means to increase F&V intake – through their influence on availability, access, pricing, promotion and information on the health properties of F&Vs . Churches, childcare centres and the broader community may also represent effective settings to implement environmental initiatives. According to Glanz & colleagues:"Policy and environmental approaches may have greater impact [on F&V consumption] because they influence the overall environment, reach many people, and are less costly and more enduring than clinical, individually oriented, or small-group educational interventions"Unfortunately, the evidence for effectiveness in increasing F&V intake through these means is not strong (and even lacking with regard to obesity). But I don’t think that should be a deterring factor, especially given how difficult it is to actually implement an evaluation in this type of setting, let alone a rigorous one. There have been some innovative environmental initiatives that I have come across recently, which show great promise, but have not been formally evaluated (hopefully in some way soon). Descriptions and links can be found below:The New Haven Health Corner Store (US) – member corner stores add healthier choices to the aisles of chips, soda and salty snacks, such as fresh produce and low-fat dairy products. Stores also have added advertising (including an easy to identify logo) and giveaways to increase awareness among consumers about healthier choices. The website highlights a study of why it might be important to target corner storesFruixi (Canada) – Mobile F&V bike carts operated by young volunteers around Montreal parks (kind of like getting street meat). All F&Vs sold are from local producers and at prices less than what you would have to pay in grocery stores. Fruixis will soon be available around University of Montreal affiliated hospitals. Unfortunately, the service is not available in winter. Fresh Moves Mobile Product Market (US) – A great idea – retrofitting a bus to become a one-aisle produce market for underserved communities in Chicago. Conventional as well as organic and local produce are available at affordable prices. ... Read more »
Ledoux TA, Hingle MD, & Baranowski T. (2011) Relationship of fruit and vegetable intake with adiposity: a systematic review. Obesity reviews : an official journal of the International Association for the Study of Obesity, 12(5). PMID: 20633234
I am an intense believer in the social determinants of health and looking at health problems through a social-ecological lens (i.e. determinants of health exist at multiple social levels of influence and are not just attributable to the individual or to the healthcare system). I think this is why I’ve also gotten incredibly interested in politics – from this perspective, government policies can influence population and environmental health. An interesting social determinant of health, social capital, has made me realize how we as individuals can collectively make a difference in shaping the quality of our shared spaces, and potentially overall community health – through influencing policies and working with government.Social capital, a concept originating from the work of Robert Putnam, among others, embodies the norms of reciprocity (gift giving without the expectation of receiving), social and civic participation and trust in society. Another, complimentary view is that social capital refers to the network of social relationships that provide access to resources. Regardless of the definition, when you have more of these things you have more social capital (sometimes called cohesion). Although both definitions are relevant, I am speaking more to the former definition in the discussion that follows. Richard Wilkinson was the first to introduce social capital to studies on health. He found that societies that are more socially cohesive, with smaller income gaps (more egalitarian) have higher life expectancies and lower infant mortality rates. Other authors have found that societies with higher levels of income inequality and lower social cohesion have higher levels of crime and violence and higher mortality rates. At a more local level, it has been found that residents who are more involved in the community tend to be happier where they live, regardless of the physical quality of their homes. Some studies have even found that as the level of social cohesion in an area increases, the prevalence of obesity decreases. Social capital is complex – these studies show how it may influence health. An obvious explanation is that it improves the quality of our immediate social and physical environments, as well as society at large. One caveat is that social capital itself can be shaped by many different factors operating at many different levels of social organization (e.g. at the neighbourhood/community, region, province, and country level), which thus impacts the quality of our spaces. Social capital therefore, is not a one-way street, rather an intricate web of interaction. The suburban open space in question, complete with dogMy plan is to add to social capital and hopefully improve the quality of my neighbourhood, by becoming more civically engaged. I’ve read a lot lately about how greenspace can potentially be beneficial for mental and physical health, and how it is also good for the environment (I have blogged a bit about this too). I enjoy being outdoors in natural areas – it makes me happy – and I also have a dog, with no back-yard. Unfortunately there are no dog parks or interesting greenspaces within walking distance of my home. I often take my dog to an open space close by. It’s a piece of land that separates two suburban neighbourhoods, with trees and a man-made marsh that was constructed to deal with street water runoff. Other neighbourhood residents also bring their dogs, kids toboggan down the banks of the marsh in the winter, and residents of houses bordering the space often use it as their personal dumping ground (a pet-peeve of mine discussed in a previous post). There is no landscaping and the space is never maintained.Open space often used as a personal dumping ground; there's cat litter somewhere there..I stepped in itI would really like to have this space converted into a dog-friendly park (that is maintained), with perhaps a community composter (since everyone dumps their s**t anyway), and even a community vegetable garden. Although, my partner brought to my attention that probably dog parks and food don’t mix – I’ll have to think the vegetable garden through a little bit more…... Read more »
Leal C, & Chaix B. (2011) The influence of geographic life environments on cardiometabolic risk factors: a systematic review, a methodological assessment and a research agenda. Obesity reviews : an official journal of the International Association for the Study of Obesity, 12(3), 217-30. PMID: 20202135
Home cooking is where it’s at. In my view, getting people to cook at home with wholesome foods is one way to combat the obesity epidemic. And of course, home cooked meals *can* taste great; that’s chef-dependent of course. Foods prepared outside of the home are higher in calories, fat, and sodium, and a recent meta-analysis found that children and adolescents who eat shared family meals at least 3 times per week are less likely to be overweight or eat unhealthy foods than children who eat fewer shared meals. There are two main problems with home cooking, aside from the multitude of barriers to actually being able to cook (e.g. time/work schedule, knowledge and skills). Rather, these are outcomes of cooking that I will discuss based on a recent experience.First, we waste a whole lot o’ food. Research in the UK has shown that 2.2 million tonnes of food is thrown away due to cooking, preparing, or serving too much. That’s just food that we’ve managed to work with – it doesn’t include fresh produce, meats/fish, dairy, etc. In the US, 30% of all food is thrown away each year. All of this waste is obviously costly, as we’re paying for food that we don’t eat. In the case of the US, this amounts to US$48.3 billion! But food waste is also harmful to the environment. Rotting food releases methane, one of the most potent greenhouse gases. A UK research group estimates that if food were not left to rot in landfills, this would be the greenhouse gas equivalent of removing 1 in 5 cars from the road. And we can’t forget all of the fertilizers, pesticides, and energy going into growing/raising food that we just toss into the trash. Okay, home cooking is great but waste is bad. What do we do? Eating your leftovers is one way to get the best of both worlds. Hang on though, leftovers need to be handled and stored properly in order to avoid illness. I have a dietetics bachelor’s degree but am the worst for food safety (probably because more often than not I don’t get sick). I’m the one that leaves the ham sandwich in the car in 30 degree weather (that’s Celsius) all day and then eats it unperturbed on the way home from work. Or leaves a defrosting tenderloin on the top shelf in the fridge or even out on the counter for the entire day (both no-no’s). But the other day, I did get sick – not badly mind but enough to make me realize that food safety does matter if I want to avoid having to take a day off of work. My significant other thought he was doing a service (which he was) by bringing home leftovers from a conference at work. It was some sort of pasta with a béchamel sauce and chicken. We reheated it in the microwave at home and ate about half of what was brought home. The next day, we both could not stray too far from the toilet…This was no coincidence – same symptoms and the pasta was the only thing we had in common for the previous 24 hours. We threw the rest of it out.So what went wrong? I can’t say for sure because there are so many things that could have happened, but I’ll touch on a few here. It’s hard for bacteria to grow in foods that are held at temperatures less than 4°C (40°F) or more than 60°C (140°F) – in between is called the ‘danger zone’. When serving prepared hot foods, like this pasta dish, it is imperative that the food be above 60°C. Additionally, time is a factor. Food left out for more than 2 hours is more prone to bacterial contamination. Perhaps the pasta was held in this danger zone – something that caterers should know to avoid, or not thrown out after 2 hours. My partner may have also taken the pasta and unknowingly left it out for too long. Reheating the pasta at home didn’t seem to do anything. The Canadian Food Inspection Agency (CFIA) recommends reheating leftovers to 75°C – maybe we didn’t hit that mark. When other people make your food there is always the possibility that they didn’t adequately wash their hands, or use clean serving utensils or pots/containers. That’s something out of your control but you can ensure that you do these things when you make your own food. Other ways to deal with leftovers to prevent illness: Put hot leftovers in ... Read more »
Hammons AJ, & Fiese BH. (2011) Is Frequency of Shared Family Meals Related to the Nutritional Health of Children and Adolescents?. Pediatrics. PMID: 21536618
Quested T, & Johnson H. (2009) Household Food and Drink Waste in the UK. WRAP. info:/
I just got back from a conference in Montreal – one on obesity at that. The hotel, the location for the conference, held sessions on floors 1-4 and on sub floors below the lobby – ample opportunity to use the stairs. There were two main problems: 1) the stairs were confusing – you’d get up to one floor but then couldn’t find the next set of stairs to the next floor and have to walk quite a distance to get to them; and 2) there were escalators in between these floors in plain sight from the main floor lobby, somewhat easy to navigate, and were a brilliant, flashy gold colour. I, more often than not, took the flashy-fancy escalators. In my last post, I reflected on how easy it is to be physically inactive nowadays and went on to discuss point-of-decision prompts as a way to get people to use the stairs instead of escalators or elevators. These prompts appear promising, but what if buildings are not designed to make taking the stairs easier or enjoyable, such as was the case at the obesity conference? To answer this, in today’s post I will discuss the recommendations provided by New York City’s Active Design Guidelines to make buildings enjoyable places to walk – and some instances make walking the more convenient form of transportation. The guidelines were developed based on the best available evidence in the literature, as well as on current best practices in architecture and design. So keep in mind that even though these are recommendations there is no guarantee that they’ll work to increase physical activity. At the same time however, they have direct synergies with sustainability, such as decreasing electricity and building material use (so, in my opinion, are at least worth considering). There are three main categories of building design recommendations that I’ll touch on in my discussion below: 1) Elevators and escalators; 2) stairs; and 3) supportive design elements. I think that the more recommendations implemented, the more likely that building design will be successful at increasing the physical activity levels of its users. Design of elevators and escalatorsMechanized options for travel between floors should be designed to be hard to find, or at least less prominent (not the case for the escalators at my conference). Decreasing their speed can make them less efficient than walking, and save on electricity. Installing the minimum number of elevators required by building codes could also decrease efficiency by increasing volume of users. Other ways to make elevators less efficient than walking include programming them to: Be skip-stop (they don’t stop on every floor so you have to get out and walk up a floor);Open at each floor (this may not make sense in buildings with 30+ floors);Open and close very slowly (which is beneficial for persons with disabilities) Design of stairsStairs should be the main attraction. They should be visible from the lobby and elevators, and always located close to building occupants (i.e. office areas). One way to draw attention to them is to put the lobby of the building on the second floor, accessible from the ground floor via a grand staircase, with elevators accessible only at the lobby (meaning people have to use the stairs to access the elevators). Point-of-decision prompts can also help (as I discussed in Part I). A great example of making stairs interesting -maybe a bit extreme and perhaps not sustainable, but cool nonetheless- is the piano stairs: Additionally, stairs should:Open to and be accessible at each floor (no locked doors);Be seen – if stairwells are a must they should be transparent;Receive large amounts of natural light;Be well ventilated... Read more »
Bloomberg MR, Burney D, Farley T, Sadik-Khan J, & Burden A. (2010) Active Design Guidelines: Promoting Physical Activity and Health in Design. City of New York. info:/
We all know that we are not getting enough physical activity these days. In fact, 52% of Canadian adults 20 years of age or older are considered inactive, and 88% of children aged 5-19 years don’t meet Canada’s physical activity guidelines. It’s one out of many reasons why the prevalence of overweight and obesity is so high. But physical activity has other health benefits, in addition to staving off obesity and cardiovascular disease, such as reducing stress and improving concentration, promoting correct physical growth in children, and maintaining mobility and independence in the elderly. The problem is that it’s just too easy to be physically inactive. Our society has, for all intents and purposes, engineered physical activity out of the built environment – important, especially when you consider that schools and many jobs require us to be sitting for most of the day to begin with. Take for instance stair climbing; it is a great means of increasing cardiovascular output, but the need for it has all been eliminated by the design of modern buildings. Escalators and elevators are easy to access and do the work for us, but are energy guzzlers - elevators account for 3-10% of a building's energy uses. Stairs, our healthy and environmentally friendly benefactor, are difficult to find, often ugly and dark, and sometimes invite anti-social activity. It’s no wonder people don’t use them.Can we design public buildings then to increase physical activity? This is a burgeoning area of research with evaluation studies still lacking. In the next post, I’ll discuss some recommendations made by the City of New York in their Active Design Guidelines, based on the best available evidence and best practices. However, I’d like to discuss here point-of-decision prompts as a way to get people to use the stairs instead of escalators and/or elevators – a bit different than design per se but related and still very relevant and interesting. I was actually pleasantly surprised to see that there was a large enough body of research to warrant a systematic review on the subject.Motivational sign from Kino Québec (not sure why the guy is blue). More info is available at: http://www.kino-quebec.qc.ca/marche/promotions.asp This very recent systematic review was published in the Scandinavian Journal of Public Health in 2010 and included 25 studies that examined the role of posters (n = 16), stair-rise banners (n = 5), both (n =4), or posters and floor graphics (n = 1) in helping people decide to take the stairs versus elevators (n = 8) or escalators( n = 18). The majority of studies were conducted in public transit stations (e.g. train, bus, airport), shopping malls, or office buildings. All used the interrupted time-series design (before-after where the ‘before’ sample does not necessarily contain the same individuals as the ‘after’ sample). Of the 42 comparisons (more than one comparison often conducted in a study), 31 reported modest but significant increases in stair climbing, 10 reported no association, and 1 reported an inverse association. The non-significant results were more likely to be reported by studies examining stairs versus elevators. There were no consistent differences between men and women. Of the significant studies that calculated odds ratios, those in favour of the intervention ranged from 1.05 – 2.93. Results appear promising with perhaps more work to be done to get people to use stairs instead of elevators versus escalators. Motivational sign from NYC Active Design GuidelinesThere are some important things to keep in mind about this review and the included studies:Follow-up times were fairly short (at most 6 months). Some studies found that stair climbing decreased back ... Read more »
Nocon M, Muller-Riemenschneider F, Nitzschke K, & Willich SN. (2010) Increasing physical activity with point-of-choice prompts -- a systematic review. Scandinavian Journal of Public Health, 633-38. info:/
Hat tip to Atif who brought this story to my attention this past November. Over the last three years the Bloomberg administration has created over 200 miles of bike lanes and passed several bicycle friendly laws. This has been to the detriment of infrastructure supporting car use. To me, this is great news but to others that have a special attachment to their cars, or fear delivery trucks won’t be able to make their morning deliveries, this is terrible news. A similar story is starting to unfold in Ottawa; a ‘not-in-my-backyard’ mentality.There is a war raging now in New York City – over bike lanesIn NYC, vocal opposition by drivers and elected officials has led to the removal of newly established bike lanes in Brooklyn and on Staten Island – lanes that communities originally wanted after extensive public consultation. It seems that in the US, if you don’t agree with the government and don’t get your way, then you sue (if you have the means that is). That’s precisely what’s happening in New York City. A bike lane along Prospect Park West, a road forming the boundary between the Prospect Park and the well-to-do neighbourhood of Park Slope, is at the centre of a lawsuit brought on by wealthy, well-connected Brooklyn residents. According to the Times, almost three quarters of Park Slope residents are in favour of the bike lane; however this drops to 50% of residents who live along Prospect Park West, prime real-estate that overlooks the park. A nice butt shot of me on one of NYC's off-road bike lanesOpponents have cited many faults by the DOT - erroneous, misleading statistics, lack of transparency and public consultation, sub-par design, reduced room for cars, reduced safety, to name a few. As reported by the Times, room for the legal complaint to be made stems from a state statute that allows challenges to government actions considered to be arbitrary or unfair. Nowhere do I see these two requirements being met by bike lane opponents. It just seems like a complaint against changing the status quo and making life slightly less convenient. From an overall perspective, DOT statistics show that bicyclist fatalities and crashes in NYC have decreased almost 19% from 2006 to 2010, with the number of cyclists doubling from 2006-2010, and increasing 13% from 2009-2010. However, I did not come across stats on percentage of mode share (although this is likely premature as I discuss below). For Prospect Park specifically, DOT reports that crashes involving injuries are down 63%, speeding by cars is down from 75% to 20%, and cycling on the sidewalk is down 80%. Area residents and users of the lane also report feeling safer. Opponents, however, feel that the numbers have been deliberately 'fudged'. As reported by TransportationNation, the lawyer of the group filing the lawsuit stated:“Everyone should be concerned about DOT’s misuse of the data. Everyone. This case is about a government agency wrongfully putting its thumb on the scale by fudging the data and colluding with lobbyists. That is not what ‘public integrity’ means. Some people on both sides of the issue are affluent and have political connections. So, the continuous, one-sided name-calling is hardly appropriate. But, more importantly, it keeps people from focusing on the real issue in the case, which I suspect is the true aim.”Clearly an independent third party needs to evaluate use and safety of biking infrastructure if these statistics are to be believed. At the same time, new biking infrastructure will take some getting used to (by users and non-users alike) and time to increase awareness in the general NYC community (to increase the number of users), so an in-depth evaluation right away, in my mind, is premature. Additionally, it’s pretty hard to argue with people who think that a bike lane is a terrorist plot. I am truly amazed and saddened by this on-going saga. I mean they are bike la... Read more »
WHITEHEAD, T., SIMMONDS, D., & PRESTON, J. (2006) The effect of urban quality improvements on economic activity. Journal of Environmental Management, 80(1), 1-12. DOI: 10.1016/j.jenvman.2005.01.029
Lee, A., & March, A. (2010) Recognising the economic role of bikes: sharing parking in Lygon Street, Carlton. Australian Planner, 47(2), 85-93. DOI: 10.1080/07293681003767785
Is being in a ‘green’ environment good for our health and well-being? Are we starved of this connection with nature? Richard Louv thinks so, author and chairman of the Children and Nature Network. He has coined the term ‘nature-deficit disorder’ to reflect the psychological, physical and cognitive repercussions of our lack of contact with nature, especially among children in their vulnerable developing years. Although Mr Louv specifies that this is not a formal diagnosis, I am not in love with the term because I find that it does bring forth this meaning to me. I admit that I haven’t yet read “Last Child in the Woods” (am planning to once the single copy on loan at UO has been brought back finally), but I wanted to investigate the scientific evidence for this idea a little further. And then discuss, in the grand scheme of things, whether the evidence really matters anyway.The Child and Nature Network has been busily compiling together the evidence base for nature and health. While it is important for an advocacy group to do this, I find it somewhat biased from my perspective as an epidemiologist – where are the studies that examined these types of relationships but didn’t find anything? So like any good epidemiologist would do, I set out to look for some systematic reviews and meta-analyses. Without much looking I came across a recent systematic review that sought to examine studies that compared health outcomes in natural and synthetic environments, usually over a short duration. Twenty-five studies were included, with most being cross-over or controlled trials; although seven were randomized controlled trials. The most common outcomes were scores on various self-reported emotions. This is somewhat problematic in that respondents often can guess what is being studied (especially if it’s a non-randomized cross-over study) and will sometimes adjust their responses. More robust study designs (such as RCTs or at least randomizing order of exposure to each of the environments) can help to mitigate this bias. Other common outcomes included physiological measures such as cardiovascular functioning (blood pressure or pulse), and hormone levels (salivary or urinary cortisol, amylase, and adrenaline). Less common outcomes included immune function, physical activity, motor performance, cerebral brain activity, engagement, memory recall, and sleeping hours. There were too few of these to conduct a meta-analysis so I won’t discuss them further – you can get more info here. The meta-analysis revealed (see Table 1 above) a possible benefit of natural versus synthetic environments for energy, anxiety, anger, fatigue and sadness. No benefit was seen for more objective measures like blood pressure and cortisol levels. There was a benefit reported for attention before effect sizes were adjusted for baseline levels. Because only 3 out of the 5 attention studies had baseline measures, this may have reduced statistical power, as the effect size decreased only slightly but the confidence interval increased. Important points to keep in mind: · Most of the included studies were experimental in design and included college students, adult males, or physically active adults – so the overall finding of the meta-analysis is not generalizable to the overall population, or to children · Outcomes were examined over a very short duration. Some beneficial effects may take longer to manifest and/or require repeated or prolonged exposure to the natural environment· We’re not sure what exactly in the natural environment is responsible for these beneficial effects. Does this matter?· I am a little concerned with regard to the small number of studies, as well as study quality (this was not formally assessed). We may find a different association with a larger number of high quality studies What does this all mean then? Over the short-term natural environments may reduce negative emotions and improve energy levels but they don’t appear to improve some cardiovascu... Read more »
Bowler DE, Buyung-Ali LM, Knight TM, & Pullin AS. (2010) A systematic review of evidence for the added benefits to health of exposure to natural environments. BMC public health, 456. PMID: 20684754
As society becomes more plugged in, it is more and more important to get ourselves, and especially our kids, outside to play. Play is important for children in terms of cognitive, emotional, social, and physical development. We know in Canada that children are not getting enough daily physical activity, and we as a nation are not doing nearly enough to combat this problem. The author, Richard Louv, has even coined the term ‘nature deficit disorder:’ behavioural problems resulting from a lack of contact with the outdoors – a subject that I will cover in a forthcoming post. This lack of play in the outdoors is a multi-faceted problem that will require solutions at various levels of social organization (the same could be said for diet). However, I’d like to focus on one of those potential solutions – a thought (obviously not unique) that came about during a recent trip to Sweden. I was at a conference in Stockholm last summer and toured around Sweden a little bit afterwards. One of our last stops was in Sweden’s third-largest city, Malmö – just across the bridge from Copenhagen, Denmark. When searching for one of Malmö’s most famous buildings, the Turning Torso, we came across the coolest skate/climbing park I have ever seen. Of course, being a climber myself, I had to try out the man-made boulders with realistic rock-like features and climbing-gym holds. Each of the large boulders (there were three) were surrounded by a layer of pebbles about half a foot deep - to absorb the impact of a fall. Climbers and non-climbers alike were trying their hand at different routes to the top. The skate park was huge with a variety of features ranging from bowls, to rails, steps, gaps, and boxes. There was something for all skill types (certainly not dominated by experts only) and included skateboarders, rollerbladders and cyclists. I couldn’t stop watching the activity – from the very young (about 5 years of age) to the middle-aged (I thought I saw some 40-year olds trying to keep up). I later found out that this is considered by some to be one of the best skate parks in the world.This travel blog photo's source is TravelPod page: MalmöAll of this was free, in view of some incredible scenery (the Turning Torso and harbor front), and in a safe, very low vehicular traffic zone. The idea of this park is what we need everywhere – it doesn’t necessarily have to be a skate or climbing park – but something that is of high quality, in an interesting and safe area, will pique children’s curiosity and get them playing. Children can be exposed to different types of play that they wouldn’t normally be able to afford (rock climbing for example). A skate/climbing park in Hull, QC I realize money is an issue, and likely the reason Sweden can afford to build world class free skate parks may have to do with their welfare taxation system. However, much of a park’s quality and usefulness can come from where it is located. In Hull (a city in Quebec, Canada), for example, a much simpler skate/climbing park was built. It is unfortunately located on a very busy, uninteresting street. This is perhaps why I see only a few children at any one time using it, and never young children (I know it’s not a great comparison when the photo was taken in early spring..nonetheless). Additionally, play spaces can be constructed out of natural materials located nearby and strategic placement of indigenous plants. A natural playground. Photo credit: Playscapes Safety of play is another issue. Parents fret about children doing things like skateboarding, biking, rock climbing (my mother still does), playing balance beam, etc. Perhaps for good reason, as ... Read more »
Healthy Active Living . (2010) Active Healthy Kids Canada. Healthy Habits Start Earlier Than You Think. The Active Healthy Kids Canada Report Card on Physical Activity for Children and Youth. Active Healthy Kids Canada. info:/
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