A new study has found that between 1983 and 1999, the death rate in women increased in a large number of the worst-off counties in the US, primarily because of chronic diseases related to smoking, high blood pressure, and obesity. As a result of this stagnation or decline in the health of the worst-off segment of the population, inequality in life expectancy across different counties of the US worsened.

Majid Ezzati of Harvard University and colleagues analyzed death rates in all counties of the US states plus the District of Columbia over four decades, from 1961 to 1999. They obtained data on number of deaths from the National Center for Health Statistics (NCHS) and data on the number of people living in each county from the US Census. NCHS did not provide data for subsequent years. They broke the death rates down by sex and by disease to assess trends over time for women and men, and for different causes of death.

Over these four decades, the researchers found that the overall US life expectancy increased from 67 to 74 years of age for men and from 74 to 80 years for women. Between 1961 and 1983 the death rate fell in both men and women, largely due to reductions in deaths from cardiovascular disease (heart disease and stroke). During this same period, 1961–1983, the differences in death rates across different counties also fell.

However, beginning in the early 1980s the differences in death rates across different counties began to increase. The worst-off counties no longer experienced a fall in death rates, and in a substantial number of counties, death rates actually increased, especially for women, a shift that the researchers call ‘the reversal of fortunes.' This stagnation in the worst-off counties was primarily caused by a slowdown or halt in the reduction of deaths from cardiovascular disease coupled with a moderate rise in a number of other diseases, such as lung cancer, chronic lung disease, and diabetes, in both men and women, and a rise in HIV/ AIDS and homicide in men.

These results, say the authors, show that "the 1980s and 1990s marked an era of increased inequalities in mortality in the United States." These widening inequalities, they say, are "particularly troubling because an oft-stated aim of the US health system is the improvement of the health of all people, and especially those at greater risk of health disparities."

Citation: Ezzati M, Friedman AB, Kulkarni SC, Murray CJL (2008) The reversal of fortunes: Trends in county mortality and cross-county mortality disparities in the United States. PLoS Med 5(4): e66.