Obesity and the Built Environment

In response to Matt’s question as to how the built environment affects obesity, I thought I would take a look at an article about just that. In this article, “Features of the Built Environment Related to Physical Activity Friendliness and Children’s Obesity and Other Risk Factors,” researchers asked the questions: What are the relationships among physical activity friendliness of neighborhoods and the prevalence of obesity, central adiposity, and hypertension among children? And What are the relationships among environmental features related to physical activity friendliness of neighborhoods and children’s risk factors controlling for poverty and education? Previous research has been mixed on these issues, so they were looking to articulate the association a little more clearly.

            Researchers used the Hierarchy of Walking Needs model to frame their work. Hierarchy of Walking Needs is basically Maslow for physical activity: people need to have their basic needs of safety met before they can exercise for fun. This model looks at a four needs scale: accessibility, safety, comfort, and pleasurability. The study looked at block groups in an area of St. Louis where kids had previously participated in a cardiovascular risk survey, so the researchers already had data for things like BMI, waist-hip ratio, and blood pressure. They compared this data to a survey they did detailing the built environment in terms of the Hierarchy of Walking Needs. 

 They found that accessibility was significantly and negatively correlated with the prevalence of obesity and height-to-weight ratio, but none of the other stages in the Hierarchy were significantly associated in any way. There were, however, negative correlations between poverty and activity friendliness, and pleasurability. When the data was adjusted for education, accessibility was not related to obesity or waist-hip ratio. When poverty was controlled, waist-hip ratio was correlated negatively with accessibility.

            The article’s conclusion was that more work needs to be done to really understand the way the built environment affects obesity, but it does appear that accessibility could have an association with obesity indicators. This could mean that having access to a playground means kids exercise more and are less obese; or, it could mean that people who have more money have less obese kids because of other factors.

            I’m skeptical of a lot of the associations made between kids’ playtime and obesity indicators based on the research I’ve done for this and other classes this semester. There just isn’t a lot of literature suggesting that physical activity affects obesity in the way one would expect it to. In fact, I keep seeing studies where people overeat when they are more active because of perceived (or in some cases, actual) hunger. I have so much anecdotal evidence for this. As an endurance athlete, when I’m training hard (2-3 hours of intense exercise per day), I am always five pounds heavier than in the off-season. Part of this is hydration, but in all honesty, mostly it’s because I think I can eat anything I want. In my minimally-informed opinion, I think that the case of financial status being associated with better nutrition has more to do with obesity in this study than physical activity. Thoughts? Hannah?