No surprise that a reader points out that healthier areas seem to map onto "Blue" areas of the United States. But there is actually more to this than meets the eye: Are Republicans Healthier Than Democrats?:
In the International Journal of Epidemiology, S. V. Subramanian and Jessica Perkins write that, after controlling for age, sex, race, marital status, religious service attendance, highest educational degree, and total family income, Republicans were 25% less likely than Democrats to report being in poor health. They find a key component of this to be smoking: after controlling for that above list of variables, Republicans were 15% less likely to be smokers.
Remember that though Democratic areas tend to be wealthier, the wealthier individuals within Democratic regions tend to be more Republican.