Variation in life expectancy across counties in the United States is substantial and not fully explained by traditional social determinants of health, such as race and socioeconomic status.

A recent study in Health Affairs finds that life expectancy is more broadly linked to individual and community-level factors ranging from the burden of disease to the safety of neighborhoods. It is the first study to establish a relationship between a summary measure of population well-being and life expectancy in a nation sample of 3,092 counties.

Researchers used county-level estimates to determine whether population well-being — a comprehensive measure of physical, mental and social health — helps explain geographic variation in life expectancy. They found that for every standard-deviation (4.2 point) increase in the average county well-being score, county life expectancy was 2.6 years higher for males and 1.9 years higher for females. Even after race, poverty and education were controlled for, life expectancy and well-being remained positively associated.

The researchers also noted that the counties with lower life expectancies are located in the South and had a higher percentage of blacks, lower education levels and higher poverty rates compared to those with higher life expectancies.

"Well-being includes not only the absence of disease, but also a sense of opportunity, happiness and lack of stress," according to the report authors.

All six of the domains composite well-being, physical health, emotional health, life evaluation, healthy behaviors, basic access, work environment were associated with life expectancy. Researchers weren't surprised to find that physical health and healthy behaviors had an association, but they also demonstrated significance in the role of life evaluation (satisfaction and optimism about the future) and basic access (perception of safety and access to housing and healthcare).

The researchers recognize their findings are strengthened by the results of other studies. Together they show happier individuals make better life choices, engage in healthier behaviors and have stronger immune system function, while stress and negative emotions increase inflammation that leads to decreased longevity.

Their findings reinforce the need to take a broader view of life expectancy and to go beyond an emphasis on the healthcare system and traditional social determinants of care. The study highlights the importance of extending out to social supports, community involvement and the impact social and economic policies have on individual communities.

Well-being can help explain geographical disparities in life expectancy and is an important metric of a population's health and longevity. It holds promise for helping to shape interventions and initiatives aimed at improving the health of local populations.