Wednesday, October 19, 2011

The Link Between Povery, Obesity and Diabetes

Having to pay for a portion of any health care leads to decreased access. Electronic medical records result in increased quality.  Primary care causes lower costs.  The Disease Management Care Blog is responsible for the DMCB spouse's migraines.  While each assertion may be technically true, the real underlying question is "By how much?"

That's why this New England Journal paper "Neighborhoods, Obesity and Diabetes - A Randomized Social Experiment" by Jens Ludwig and colleagues that examines the association between poverty and diabetes is important.  Researchers have known that low income can lead to preference for the "cheap calories" in refined and high fat foods which, in turn, lead to a high rate of obesity among indigent persons.  Now we have a better idea on how much.

Ever hear of the "Moving to Opportunity" demonstration project?  Neither did the Disease Management Care Blog, but this was a demo designed to test the long term impact of housing and poverty on health and well-being.  In the study, females with children who were candidates for public housing assistance were entered into a lottery that randomly assigned participants to one of three groups:

1) a low poverty voucher group that could use their vouchers to rent housing in a census tract with less than a 10% poverty rate (N=1425).  After one year, persons assigned this group could move anywhere they wished;

2) a traditional voucher group that could be used anywhere (N=657);

3) a control group that was SOL (N=1104).

The women were asked questions about their health at baseline, including height, weight and also provided blood samples to check an A1c to assess the presence of diabetes mellitus.  They were then followed for approximately 10 years.

Not all persons completed the follow up, so the authors used an "intention-to treat" analysis.  The rates of poverty are here, while the rates of obesity and diabetes are here.  The low poverty voucher group not only had lower rates of obesity (defined as a BMI greater than 35) but a lower rate of abnormal A1cs (16.3% vs. 20% in the control).  The traditional voucher group had lower numbers vs. the controls but they failed to achieve statistical significance.  It appears, based on this study, that living in a low poverty neighborhood reduces the rate of obesity and diabetes in the absolute range of 3% to 4%.

The authors correctly point out that not all persons in the study completed the follow-up, which could have biased the results.  In addition, the A1c results don't account for the possibility that more persons in the voucher group may have had their diabetes successfully treated.  Last but not least, much of the data were self reported.

The DMCB was surprised that poverty seemed to directly account for a relatively small amount of "new" disease.  On the other hand, an additional 3-4% involving millions of U.S. citizens represents a public health disaster.  Based on these data, we have a better insight on the role of poverty in diabetes and can point to at least one Federal program where taxpayers appear to have gotten their money's worth.

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