A fascinating study by The Health Inequality Project looks at the relationship between income and life expectancy in the United States. Given the growing income disparity in America, this study provides a very interesting look at how socioeconomic standing affects health which ultimately impacts longevity. The authors of the study sourced pretax household earnings data for for the period between 1999 and 2014 from 1.4 billion tax records (without referencing personal information) and mortality data for the same period from Social Security Administration death records. After correcting for race and ethnicity, this data was used to estimate life expectancy at age 40 by household income percentile, sex and geographic area using 741 commuting zones through the nation, a typical measure of local labour markets, which allowed the authors to look at how longevity varies by region. In total, the sample consisted of 1,408,287,218 person-year observations for individuals between the ages of 40 and 76 with a mean age of 53 and median household earnings of $61,175 annually.
Here are some of the results:
1.) Men in the bottom 1 percent of the income distribution at the age of 40 years had an expected death age of 72.7 years.
2.) Men in the top 1 percent of the income distribution had an expected death age of 87.3 years, 14.6 years or 20 percent longer than men in the bottom 1 percent.
3.) Women in the bottom 1 percent of the income distribution at the age of 40 years had an expected death age of 78.8 years.
4.) Women in the top 1 percent of the income distribution had an expected death age of 88.9 years, 10.1 years or 12.8 percent longer than women in the bottom 1 percent.
Here is a graphical representation of the findings:
The authors observed that the longevity gap between the rich and the poor has grown rapidly over time; from 2001 to 2014, the wealthiest Americans gained roughly three years in longevity compared to nothing for the poorest among us.
Here is an interesting graphic which shows the geographic complexity of life expectancy in the bottom 25 percent of earners:
Outside of Nevada and parts of Wyoming, there is a rather clear geographic distribution of lower-earning Americans who have a shorter life expectancy; the shorter life expectancy belt runs through the central United States, connecting the former industrial heartland of Michigan, Indiana and Ohio, running diagonally in a northeast-southwest direction through Kentucky, Arkansas, Oklahoma, Kansas and down to Texas.
At the city-specific level, for the bottom quartile, longevity is highest in New York City, Santa Barbara, San Jose, Miami and Los Angeles. Longevity for the bottom 25 percent of earners is lowest in Tulsa, Indianapolis, Oklahoma City, Las Vegas and Gary (Indiana).
We generally think of income inequality in terms of its impact on our wealth; this study shows that there is a substantial impact of lower incomes on longevity with the poorest American men and women having lives that are shorter by a decade or more than the wealthiest Americans. While we assume that differences in life expectancy among poorer Americans is associated with differences in access to health care, this study shows that the poor who live in cities with highly educated, affluent residents that have high levels of local government expenditures on health care still experience shorter lives than their wealthier counterparts.