DNA or zip code? Which has greater impact on your health? Of course the answer is the same as it ever was. Both! This study in Nature was interesting though in it’s methodology. It used the Aetna database and found 56,000 twin pairs and studied them until age 24 (while they were on their parents insurance plan). Twins offer an opportunity to study the impact of genes and environment. Identical twins share the same DNA and mostly the same environment. Noting what diseases affect one twin pair vs the other or both helps dissect a disease state into its genetic and environmental components. In this study about 40% of diseases had a genetic component and 25% were clearly environmentally influenced. The rest were unaccounted for. Zip codes had a great influence. Poverty being the most impactful. When it comes to obesity, zip codes with higher median income (e.g San Francisco) had a much lower prevalence of obesity that poorer zip codes (e.g rural Mississippi). While not earth shattering in it’s conclusions, this well done study lays more groundwork for further research using the same methodology. I take optimism from these results. One need not feel trapped by their genetics. If you have relatives who have a high incidence of heart disease, cancer, obesity, etc., you are not predetermined to suffer the same fate. You can control your environment. Maintain a healthy body weight, eat well, exercise regularly, don’t smoke and you can carve your own path to health irrespective of how your relatives fared.