Monday, May 05, 2008

The Rural South--Epidemiological Reality

Recently, our local TV news has been reporting a new study indicating that life expectancies for rural Appalachian women have decreased in the last twenty years. They have accompanied this with the usual admonitions to eat healthful foods, exercise, and quit smoking. I was interested to read this newspaper story, Southwest Va.'s Mortality Mystery--More Than Diet Behind Women's Sharp Life Expectancy Drop by Theresa Vargas,Washington Post, April 26, 2008, and to follow its link to the original story, Eight Americas: Investigating Mortality Disparities across Races, Counties, and Race-Counties in the United States.

The Washington Post article features a discussion of the usual "lifestyle-related" mortality risks but also notes:

Residents will tell you little distinguishes the city of Radford and neighboring Pulaski County from elsewhere in rural America. That is what troubles health-care workers here most about a new study that found a sharp drop in life expectancy for women in the two communities.

According to the study, life expectancy for women dropped in nearly 1,000 counties but fell most in Radford and Pulaski. In 1983, life expectancy for women in the two jurisdictions was about 84 years. By 1999, it had dropped 5.8 years, to 78. No other jurisdiction in the nation had a decrease of more than 3.3 years.

This begins to get at what is surprising about the "Eight Americas" study. It looks at mortality data county by county over 20 years, for the entire United States, and identifies eight economic-geographic-racial clusterings. Since the article is in the open-source journal PLoS Medicine, you can look at a detailed data summary, the entire article, and all the figures and maps.

The eight Americas classification reveals that within the white population there is a wide variation in health experience that cannot be explained by differences in average income: low-income white rural populations in Minnesota, the Dakotas, Iowa, Montana, and Nebraska (America 2), with a life expectancy of 76.2 and 81.8 y for males and females, respectively, have a substantial advantage over the rest of white America, despite a large income disadvantage. Low-income whites in Appalachia and the Mississippi Valley (America 4), with an average income level similar to that of America 2, have a life expectancy equal to those of Mexico and Panama. The life expectancy gap between whites in America 2 and America 4 was 4.2 and 3.8 y in 2001 for males and females, respectively, comparable to the 6.4- and 4.6-y gaps between whites and blacks as a whole. The gap between whites in America 2 and America 4 has in fact increased since 1982, when it was 3.0 and 2.4 y for males and females respectively; between 1982 and 2001 life expectancy among females in America 4 declined from 78.2 y to 78.1 y.

Both white and black low-income rural Southern populations have a shorter life expectancy than their more affluent counterparts ("White Middle America" and "Black Middle America") in other areas of the US, but there is one white, rural, low-income population that has a longer life expectancy than "White Middle America." Low income, chemical exposure, and inconvenient access to health care are not the only reasons America 4 fares worse than America 2. To my mind, the study identifies rural white Southerners and rural black Southerners, as epidemiologically distinct groups, separate and unequal from their counterparts in other parts of the United States. Where Lillian Smith and W.J. Cash critiqued Southern cultural identity, this study identifies a biological definition for the region distinct from income and population density.

The traditional emphasis of the US health system has been on children and the elderly, as, for example, illustrated by the low levels of resources devoted to injury prevention and tobacco control compared with immunization. This emphasis may have partly contributed to substantially lower disparities in these age groups relative to young and middle-aged adults. On the other hand, the emphasis on children and the elderly has treated many of the diseases that are important contributors to young and middle-aged adult health disparities, and their risk factors, as either the responsibilities of individuals (alcohol, tobacco, obesity, and dietary determinants of blood pressure and cholesterol, like salt) or in the domain of clinical care (blood pressure and cholesterol)....It is when the public, community and professional groups, media, and politicians focus attention on what is being achieved, and why efforts are working in some places and not others, that the culture of accountability for health outcomes will be strengthened.

The study is an interesting data-mining exercise, intended to point the way to more intensive public health research. I grew up in a county included in "America 2," and now I live in a different rural area in "America 4." I had always thought, terrain aside, that southwestern Iowa was surprisingly similar to Pocahontas County. Now I'm wondering whether I shouldn't be trying to identify the differences.

In case you're interested, here's the abstract for the article:

Eight Americas: Investigating Mortality Disparities across Races, Counties, and Race-Counties in the United States Murray CJL, Kulkarni SC, Michaud C, Tomijima N, Bulzacchelli MT, et al. PLoS Medicine Vol. 3, No. 9, e260 doi:10.1371/journal.pmed.0030260


The gap between the highest and lowest life expectancies for race-county combinations in the United States is over 35 y. We divided the race-county combinations of the US population into eight distinct groups, referred to as the "eight Americas," to explore the causes of the disparities that can inform specific public health intervention policies and programs.

Methods and Findings

The eight Americas were defined based on race, location of the county of residence, population density, race-specific county-level per capita income, and cumulative homicide rate. Data sources for population and mortality figures were the Bureau of the Census and the National Center for Health Statistics. We estimated life expectancy, the risk of mortality from specific diseases, health insurance, and health-care utilization for the eight Americas. The life expectancy gap between the 3.4 million high-risk urban black males and the 5.6 million Asian females was 20.7 y in 2001. Within the sexes, the life expectancy gap between the best-off and the worst-off groups was 15.4 y for males (Asians versus high-risk urban blacks) and 12.8 y for females (Asians versus low-income southern rural blacks). Mortality disparities among the eight Americas were largest for young (15-44 y) and middle-aged (45-59 y) adults, especially for men. The disparities were caused primarily by a number of chronic diseases and injuries with well-established risk factors. Between 1982 and 2001, the ordering of life expectancy among the eight Americas and the absolute difference between the advantaged and disadvantaged groups remained largely unchanged. Self-reported health plan coverage was lowest for western Native Americans and low-income southern rural blacks. Crude self-reported health-care utilization, however, was slightly higher for the more disadvantaged populations.


Disparities in mortality across the eight Americas, each consisting of millions or tens of millions of Americans, are enormous by all international standards. The observed disparities in life expectancy cannot be explained by race, income, or basic health-care access and utilization alone. Because policies aimed at reducing fundamental socioeconomic inequalities are currently practically absent in the US, health disparities will have to be at least partly addressed through public health strategies that reduce risk factors for chronic diseases and injuries.

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