ZNA’s the new DNA: How zip codes have drastic impacts on your health

ZNA's the new DNA: How zip codes have drastic impacts on your health

In January 2015, President Barack Obama launched the Precision Medicine Initiative, a plan to support research into treatment and prevention strategies that take differences between people — especially genetics — into account.

However, precision medicine can’t just look gene-deep. Where we live — the air we breathe, the water we drink, the environments around us — has a huge impact on our health and even on our DNA.

As a professor of environmental health sciences, epidemiology and medicine, and co-director of the Joint Geisinger-JHSPH Environmental Health Institute (EHI), I have been working with electronic health record data to link such environmental issues as animal feeding operations, agricultural practices, unconventional natural gas development and the built environment to such outcomes as drug-resistant infections, diabetes and asthma control, pregnancy outcomes and obesity. Working with Dr. Annemarie Hirsch, an epidemiologist in the EHI, we are seeking to discover how to translate these findings into the delivery of more precise clinical care.

Understanding more how our environment and social conditions shape our health could lead to better treatments and better preventive care. But two problems stand in our way before we can do this. The first is that these data aren’t being collected. And if we were to start collecting them, health care providers wouldn’t know how to use them.

Biology isn’t the only thing that makes us different

We know that our genetics can shape our health, but so can three other important factors. These are social determinants of health and community, and social and physical environments.

Social determinants of health include income, poverty and inequality. The social environment includes things like crime rates and the affluence of your neighborhood. When we talk about physical environment, we’re talking about whether your neighborhood is designed to be walkable, has access to healthy foods or has heavy industry.

These factors can affect your health in direct and indirect ways. For instance, breathing in a poison from a factory can directly cause asthma or cancer. Living in a neighborhood with access to healthy food within walking distance of your house can indirectly benefit your health.

In fact, many studies have documented that these three factors have a more powerful impact on health than do the individual biologic differences between people. For instance, income and educational attainment are at least as strongly associated with hypoglycemia in patients with diabetes as known clinical risk factors. Individuals living in neighborhoods with limited healthy eating and physical activity resources have a higher risk of being diagnosed with type 2 diabetes.

Dr. Risa Lavizzo-Mourey, president of the Robert Wood Johnson Foundation, stated that, “We know that a child’s life expectancy is predicted more by his ZIP code than his genetic code.”

That’s not an overstatement. There are dramatic differences in life expectancy across the United States depending on where you are born. The highest-longevity places tend to be in the Northeast and West, while the lowest is in the South. While genetics and health care are critical, others have argued that “ZIP code, race and class trump genetics and healthcare as predictors of health.”

Cracking the ZNA code

NIH Director Dr. Francis Collins recently tweeted that our ZIP code at birth is our “ZNA, the blueprint for our behavioral and psychosocial make-up.”