A new study of mortality patterns across the United States in the four decades leading up to 1999 shows that life expectancy is stagnating and even falling for many parts of the population. The researchers also found that while the differences in life expectancy across counties narrowed at first, they widened again over those four decades.

The study is is published online today, 22 April 2008, in the open access journal PLoS Medicine, and is the work of researchers from the Harvard School of Public Health, Boston and Harvard University, Cambridge, Massachusetts; the University of California, San Francisco; and the University of Washington, Seattle.

The fact that wide disparities in life expectancy exist among groups in the US population is not new. Women tend to live longer than men, white Americans have longer life expectancy than black Americans, and poorer people tend to spend fewer years on this earth than wealthy people. Another important determinant appears to be where one lives in the United States, since social conditions and differences in healthcare systems also play a role.

While overall, life expectancy has generally risen across the US in the four decades leading to the close of the last century, until this study, it was not possible to see that statistic broken down into small geographic units – counties. Such information is valuable because it allows researchers and policy makers, as well as the interested general public, to make comparisons among groups of people governed by the same administrations.

In this study, the researchers examined the differences in mortality, or death rates, from 1961 to 1999 among all the counties of the United States plus the District of Columbia. In the United States, a county is a tier of government that generally sits below state and above township level.

The data on death rates came from the National Center for Health Statistics, and the data on population numbers in counties came from the US Census.

The researchers were able to analyse trends in death rates by gender and by cause of death for the different gegraphic areas.

The results showed that:

  • Over the four decades 1961 to 1999, overall US life expectancy went up from 67 to 74 years for men and from 74 to 80 years for women.
  • From 1961 to 1983, the death rate fell in both men and women, mostly because of reductions in fatal events due to heart disease and stroke.
  • Over the same period (1961 to 1983), the differences in death rates among different counties went down.
  • But, from the early 1980s, these differences went up again.
  • The worst off counties no longer saw a fall in death rate, and in many of them it went up, especially for women. The researchers called this “a reversal of fortunes”.
  • 4 per cent of men and 19 per cent of women experienced either decline or stagnation in mortality from the 1980s.
  • This “stagnation” in the worst off counties was mainly due to a levelling off in the reduction of deaths due to cardiovascular diseases and a rise in deaths due to other diseases such as lung cancer, diabetes and chronic lung disease, in both men and women, and an increase in HIV/AIDS and homicide in men.

The researchers summarized their key finding as being that the differences in life expectancy among US counties from 1961 to 1999 became smaller at first, but then widened again.

Looking at the pattern from 1980 to 1999, the findings suggest that those who were already disadvantaged did not experience increased life expectancy compared to the advantaged, and some even became worse off than before.

The editors suggested that the study showed “how important it is to monitor health inequalities between different groups, in order to ensure that everyone, and not just the well off, can experience gains in life expectancy”.

The authors said the reversal of fortunes they found for a minority of the population was disturbing because the US health system states its aim is to improve the health of “all people, and especially those at greater risk of health disparities”, as quoted by the US Centers for Disease Control and Prevention (CDC).

In a press statement, the lead author of the study, Majid Ezzati, Associate Professor of International Health at Harvard School of Public Health called the result a major public health concern and said:

“There has always been a view in US health policy that inequalities are more tolerable as long as everyone’s health is improving.”

“There is now evidence that there are large parts of the population in the United States whose health has been getting worse for about two decades,” he added.

Most of the counties that experienced the worse downward trends in life expectancy were in the Deep South, along the Mississippi River, and in Appalachia, toward the southern regions of the Midwest and into Texas.

Director of the Institute for Health Metrics and Evaluation at the University of Washington and study co-author Christopher Murray said:

“Life expectancy decline is something that has traditionally been considered a sign that the health and social systems have failed, as has been the case in parts of Africa and Eastern Europe.”

“The fact that is happening to a large number of Americans should be a sign that the US health system needs serious rethinking,” he added.

“The Reversal of Fortunes: Trends in County Mortality and Cross-County Mortality Disparities in the United States.”
Ezzati M, Friedman AB, Kulkarni SC, Murray CJL.
PLoS Medicine Vol. 5, No. 4, e66
Published online 22 April 2008 (open access)
DOI:10.1371/journal.pmed.0050066

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Sources: PLoS Editor’s summary and abstract, Harvard School of Public Health.

Written by: Catharine Paddock, PhD