Do obese people choose obese environments?

A continuing issue regarding the influence of the built environment on health has been  whether certain types of environments: sprawled metropolitan areas or unwalkable neighborhoods cause obesity or whether obese people simply choose these areas because they support a low physical activity lifestyle or make it easier for obese people to live there.  Which came first: obesity or the neighborhood?

Part of the reason for this uncertainty is the nature of the evidence.  Most of it comes from cross-sectional data (individuals are asked questions at a single point in time). A major limitation of these types of studies is that no conclusions about the directionality of the associations can be made.

There have been some attempts to use cohort data, information on a set of individuals collected at several or more time intervals.  The problem with these datasets is that they aren’t very many of them and they tend to be small.  Small studies may lack the statistical power to identify the subtle, but important, effects of sprawl on obesity, for example.

One of the few longitudinal datasets that can be used to study the built environment is the National Longitudinal Survey of Youth (NLSY) which consists of two national samples:  persons who were born between 1957 and 1965 and the natural born children of mothers in the original cohort  (a third cohort has been established but its oldest members are only 26, perhaps not yet old enough fo use in an obesity study).  These cohorts were selected in order to enable study of how people entered the labor force and progressed their careers. These cohort has the essential features that are needed for a health and the environment study: place of residence (not publicly available but accessible upon special request), data on height and weight (collected to assess disability status) and data collected almost every other year since the cohort’s start date.

Reid Ewing used this dataset, in conjunction with his urban sprawl measure (developed in conjunction with Smart Growth America) to test the which came first problem.  What he found was that the built environment (sprawl) did not seem to be associated with obesity in longitudinal analyses.  Note that this does not directly put to rest which came first, only that the NLSY data doesn’t support the sprawl to obesity hypothesis.  But the NLSY may be too small (only about 10,000 persons) to uncover the association.  So the controversy continues.

There has been a great deal of research on residential choice.  Economists and urban planners have been curious about this for years.  They tend to find that affordability and school quality are the most important predictive factors for how a household chooses its location.  Access to jobs is also important.  These studies never included any data on walkability or urban design.  They never considered that people would choose neighborhoods based on obesity status.

So as of this time, we cannot determine which came first:  obesity or the neighborhood.

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One Response to “Do obese people choose obese environments?”

  1. She says:

    I think it is a bit of both.When I was at school, a uimimnm of 2 hours PE was incorporated into the curriculum, even if you are doing your GCSEs, and PE was not a subject you picked as an option, you had to do 2 x 1.5 hour sessions a week. When my younger cousin was doing her GCSEs 2 years ago, it was an optional thing, and she spent that time sitting on her bum at home. It doesn’t help either when the school cooks do not cook as much anymore, merely reheat stuff.My mother raised my brother and myself on her own and on a meagre income, she often took either one of us with her, on Saturday, to Walthamstow Market (it was a half hour walk from my crummy council estate). We took an interest in the fruit and veg the guys were putting into the paper bags, and when it came to the supermarket, my bro and I had a friendly competition to find the cheapest but healthiest *item which was going to be for dinner that night* I think that was half the reason she allowed us to tag along ;o) but, she did not allow my brother or me to dictate our dinners (when we had them), we only had one choice and it was either on our plate, or we go hungry. She cannot understand why one of my aunts would cook a different meal for each of her children, and then something else for herself she is the mother, she should decide on dinner not the kids (who would be more than happy to live off of burger and chips, or pizza 365 days a year). The problem at home, is that most parents dare not leave their kiddies out of their sight to go outside in the (somewhat) fresh air and play, as they are told that a paedophile is on every corner and will snatch them away, and that is only when play areas or dirt tracks are not being sold on for redevelopment (it was heartbreaking going through my old council estate to see that the play area I spent a lot of my school holidays as a child has been turned into a . car park!)We are living in a time when doctors are seeing children with Rickets again, this is a disease which has hardly been seen in the UK for nearly 80 years! Both have a part to play, people must be very naive (or extremely stupid) not to make a link between an increasing sedentary childhood, increasing consumption in what I can only call crap , and lack of focus on physical education as a child, and their expanding waistlines!