Differences in county-level life expectancy are large and increasing, according to a new report in JAMA Internal Medicine.

Investigators looked at life expectancy from 1980 to 2014 and found life expectancy to be 79.1 years overall with the rates differing by 20.1 years between the counties with the highest and lowest life expectancy. The gap between the highest and lowest counties increased over this time period, however, but it became smaller for children and larger for adults. Socioeconomic and race/ethnicity factors, behavioral and metabolic risk factors, and health care factors each explained 60%, 74%, and 27% of county level variation, respectively.

Lead author Laura Dwyer-Lindgren told Science Daily “Looking at life expectancy on a national level masks the massive differences that exist at the local level, especially in a country as diverse as the United States…Risk factors like obesity, lack of exercise, high blood pressure, and smoking explain a large portion of the variation in lifespans, but so do socioeconomic factors like race, education, and income.

The top ten counties with the largest increases in life expectancy were spread across the US from Alaska to Florida to California, however, the counties with the top ten largest decreases in life expectancy were all in the south and 8 out of 10 were in Kentucky