It is common knowledge that average life expectancy in the United States is on the upswing. In fact, current statistics now estimate that men and women are living about six or seven years longer than they did four decades ago. While this reflects the trend for a large proportion of the U.S. population, a recent trend analysis conducted by HSPH associate professor of international health Majid Ezzati and his colleagues leads to the troubling finding that this is not the case for all areas of the country. In the April 22 PLoS Medicine, Ezzati and his group show that there are large sex-specific variations in mortality across the country, with some regions showing no improvement at all while a significant number of others even show a decline in life expectancy.
Ezzati and his group began this analysis by collecting mortality data for each U.S. county from the National Center for Health Statistics and population data from the U.S. Census. Ezzati explained that the advantage of looking at county-level data is that it provides a far better representation of mortality spread since it is the smallest geographical unit for which reliable measurements are available. County measurements also are relatively consistent over time.
Once the data had been gathered, the team was able to calculate the mortality rate for individual U.S. counties for each year since 1961. This produced more accurate estimations of life expectancy differences based on geographical location. Intriguingly, the researchers found an unusual pattern to the data. “It seemed that something started happening in the early 1980s,” said Ezzati. “After a couple of decades of mortality disparity going down, it then started to go up.” To investigate this more closely, Ezzati and his group separated the analysis into approximately 20-year time periods—one prior to and one after 1983 (the year that showed lowest cross-county mortality differences).
It appeared that in the 22-year period leading up to 1983, mortality rate seemed to be improving at a relatively similar pace across the United States. But in the 20-year period after 1983, life expectancy gains became more polarized than ever before. “Some counties started stagnating,” said Ezzati. “But the surprise was that there were a reasonably large number of counties that had gotten worse.”
This so-called “reversal of fortunes” in the worst-off counties does not reflect well on the U.S. health system, whose primary aim has been to improve the health of all populations in the country. Ezzati said, “Inequality aside, which is itself bad, the decline in life expectancy is a very troubling thing. We are now trying to look at the epidemiological drivers of this.”
