How life expectancy varies across America

By C.K. | WASHINGTON, DC

FEARRINGTON in North Carolina is a planned community modelled on an English village. It was built on the site of a former dairy farm. Stilwell, Oklahoma, also has agrarian roots: it advertises itself as the strawberry capital of the world. But a recent analysis by researchers at the National Centre for Health Statistics suggests the two communities are otherwise very different. Fearrington is home to some of America’s healthiest people, with an average life expectancy only two-and-a-half years short of a century. In Stilwell, newborns should expect to live to the age of 56. Stilwell has the same estimated average life expectancy as Somalia; Fearrington’s is 13 years higher than the average in Japan, the world’s most long-lived country.

The researchers estimated life expectancies across every one of America’s 65,662 census tracts: geographical divisions containing a few thousand people each that cover the entire country and are used for census data collection. The median estimated life expectancy across all tracts in America is 78.5 years. But 1,656 tracts see life expectancy below 70 years, and 2,511 have expectancy above 85—a 15-year gap. At the extremes there are 64 census tracts where life expectancy is estimated to be above 90, while seven see expectancies more than 30 years lower than that.

Census data points to some of the factors that lie behind this inequality. Median household income in the Fearrington tract is $81,900. The 4,630 people of Stilwell have a median household income of $25,000, less than half the national average. None of Fearrington’s children are reported to live in households below the poverty. That compares to more than half of children in Stilwell. A history of discrimination also plays a role: Chatham County, where Fearrington is located, is 96% white. Most people in Stilwell are native Americans—part of the Cherokee Nation that was forcibly relocated to the territory in 1830. The analysis suggests the bottom quarter of census tracts nationwide in terms of median household income account for 61% of the bottom quarter of tracts measured by life expectancy. The richest quarter of census tracts include 57% of the longest-lived tracts. Low life-expectancy is concentrated in the South and in tracts with a high share of minority populations.

Previous analyses of the inequality of life expectancy in America have also pointed to the huge role played by poverty in cutting American lives short. Raj Chetty, an economist at Stanford University, has studied the variation of health outcomes by income and across regions of America using tax and census data. His research suggests that the poorest 1% of women die an average of ten years earlier than the richest 1%. The richest-poorest life expectancy gap for men is 15 years.

Researchers at the Institute for Health Metrics and Evaluation also found that poverty and education were strongly linked to life expectancy at the county level. Their work suggests that low income and limited schooling were related to behavioural and metabolic risk factors including obesity, limited exercise, smoking, hypertension, and diabetes. In turn, these risk factors shortened lives.

There is a regional component to those risk factors as well. Mr Chetty found life expectancy amongst the poorest quarter of Americans differed across regions by four years for women and five for men. Once again, longer-lived regions saw lower average rates of obesity and smoking along with higher rates of exercise. Low-income individuals lived healthier and longer in affluent cities with highly educated populations and high levels of government expenditures, perhaps reflecting policies such as smoking bans or greater funding for public services.

Mr Chetty’s study argued that regional differences in life expectancy for poorer people were not significantly related to the proportion of people insured in those regions or measures of preventive health care. And health outcomes for that group did not notably improve when they become eligible for government-backed Medicare coverage at the age of 65. But the data still suggests that healthy living in the United States is a luxury good.