How ZIP Codes Predict Health Outcomes Better Than Genetics

November 8, 2026

May Le

Fountain Valley High School

11th Grade

A child born in Barry Farm, Washington D.C, would expect to live to 63.2 years old. Yet just over 10 miles away, a child born in Friendship Heights would have a life expectancy of 96.1 years. Although this is one of the most extreme examples of health disparities across the United States, it reflects the larger pattern that geographic location acts as a major determinant of life expectancy. Across the United States, lower-income neighborhoods, typically occupied by many racial minorities, face much worse health outcomes than their higher-income counterparts.

While many assume that genetics are a primary determinant of health, research suggests otherwise. According to a study conducted by the journal Nature Genetics, genetics account for 40% of conditions and diseases that develop by early adulthood, while the other 60% is determined by environmental factors, which includes stress levels, habits, and access to resources. These factors are often referred to as social determinants of health, and are highly influenced by a person's geographic location.

Individuals living in wealthy neighborhoods often have greater access to nutritious food, medical care, and reside in areas with low crime rates. The opposite is also true: those who live in lower-income neighborhoods typically face more pollution, higher crime rates, have poorer nutrition, and are less likely to seek costly medical care.

However, this correlation is widened by health inequities, or systematic, unfair, and avoidable differences in health outcomes between different social groups. Redlining, which primarily occurred in the 1930s, refers to the practice of banks and government programs denying loans and investments in minority neighborhoods. This discouraged investment in these communities, limiting the growth of essential services, including healthcare facilities.. Additionally, because redlining kept home values low, these neighborhoods often had a smaller tax base, limiting governments’ ability to fund public services. As a result, many areas struggled to establish adequately funded public health clinics, and existing facilities often remained understaffed and poorly equipped.

The effects of redlining did not disappear after these policies were banned. Neighborhoods that experienced redlining often result in limited access to quality healthcare, fresh food, safe housing, and other resources that influence health. Over time, these disadvantages build upon each other, since poor access to resources can increase stress and make healthy choices more difficult. As a result, the discriminatory practices from nearly a century ago continue to affect the health of low-income communities today.

While genetics establish a person’s baseline, the environment in which they live often changes the trajectory of their health. Over a lifetime, unequal access to healthcare, nutritious food, safe housing, and economic opportunity accumulate, producing life expectancy gaps of 15 to 30 years between neighborhoods only miles apart.