Mother Jones printed an article today by Kiera Butler and Jaeah Lee looking at the link between antibiotics and obesity.
(The Mysterious Link Between Antibiotics and Obesity:States where doctors prescribe more antibiotics also have the highest obesity rates. Why?)

The authors write: “Lately, I’ve been fascinated by a study on antibiotic prescription rates across the United States that was recently published in the New England Journal of Medicine. The researchers found a surprisingly wide variation among the states, and the rates—expressed in terms of prescriptions per 1,000 people—seemed to follow a geographical pattern: The Southeast had the highest rates, while the West’s were lower. West Virginia had the most prescriptions, and Alaska had the fewest. The rest of the country fell somewhere in between.”
Here’s a map of the findings:

The pattern looked similar to the obesity by state. Here is that map:

The authors note: “When we mashed up the data behind these maps, we confirmed the strong correlation between obesity and antibiotic prescription rates (we got an r of 0.74, for the statistically inclined). We also found a correlation between the states’ median household incomes and antibiotic prescription rates: States with below-average median incomes tend to have higher antibiotic prescription rates. This makes sense, considering that high obesity rates correlate with low income levels. (You can see the data sets for antibiotic prescription rate, obesity, and median household income level here)”

The challenge is that while we can observe patterns and find strong measures of association, it does not mean there is a causal relationship. You could look at other rates like the percent of uninsured, for example and perhaps see a similar pattern. Or perhaps the levels of toxic wastes or pesticides?

See Mother Jones article:click here

Here is a map of poverty by state for 2009: