Life expectancy at birth increased between 1980 and 2014 to 79.1 years for men and women combined, but life expectancy differed by as much as two decades between counties with the lowest and highest life expectancies, according to a new article published by JAMA Internal Medicine.
County-level data, often the smallest administrative unit routinely available in death registration data, are a chance to explore the extent of geographic inequalities in the United States.
In a population-based analysis, Christopher J.L. Murray, M.D., D.Phil., of the University of Washington, Seattle, and coauthors created annual estimates of life expectancy and age-specific risk of death for each county from 1980 to 2014; they quantified geographic inequalities for these measures to examine trends; and they looked at the extent to which variation in life expectancy can be explained by socioeconomic and race/ethnicity factors, as well as behavioral and metabolic risk factors.
The authors report:
- Between 1980 and 2014, life expectancy increased for men and women combined 5.3 years from 73.8 years to 79.1 years. For men, life expectancy increased from 70 to 76.7 years and for women from 77.5 to 81.5 years.
- There was a gap of 20.1 years between counties with the lowest and highest life expectancies.
- Several counties in South and North Dakota (typically those with Native American reservations) had the lowest life expectancy; counties in central Colorado had the highest life expectancy.
- While life expectancy grew overall for men and women combined and for each of the sexes, it masked massive variation at the county level. For example, counties in central Colorado, Alaska and along both coasts experienced much larger increases, while some southern counties in states stretching from Oklahoma to West Virginia saw very little improvement.
- County-level variation in life expectancy was explained by socioeconomic and race/ethnicity factors (60 percent), behavioral and metabolic risk factors (74 percent) and health care factors (27 percent) and, combined, these factors explained 74 percent of this variation.
Limitations of the study include that the data used for life expectancy estimates by county are all subject to error.
"This study found large - and increasing - geographic disparities among counties in life expectancy over the past 35 years. The magnitude of these disparities demands action, all the more urgently because inequalities will only increase further if recent trends are allowed to continue uncontested," the article concludes.
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