County-Level Contextual Characteristics and Disparities in Life Expectancy

Area of Science:

• Public Health
• Epidemiology
• Social Determinants of Health

Background:

• Life expectancy in the United States exhibits significant geographic variation.
• Understanding county-level contextual factors is crucial for addressing these disparities.

Purpose of the Study:

• To estimate the contribution of county-level contextual factors to variations in US life expectancy.
• To identify modifiable factors influencing life expectancy at the county level.

Main Methods:

• A counterfactual approach was used to assess life expectancy loss associated with 45 county-level characteristics in 2016.
• Data were sourced from the County Health Ranking Project and the US Small-Area Life Expectancy Estimates Project.

Main Results:

• County-level factors were associated with an average loss of 4.30 years in life expectancy.
• Adult smoking, food insecurity, and adult obesity were key contributors, accounting for 1.24, 0.89, and 0.58 years of life expectancy loss, respectively.
• These factors collectively contributed to a 3.53-year loss in life expectancy, with greater impact in socioeconomically deprived areas.

Conclusions:

• Substantial geographic variations in life expectancy exist across US counties.
• Six county-level factors significantly reduce life expectancy, underscoring the need for targeted interventions.
• Findings can inform strategies to reduce life expectancy inequalities nationwide.