A map of Americans’ health status and longevity resembles a microcosm of global health extremes. Although Asian-American women in Bergen County, New Jersey, live to an average age of 91—three years longer than women in Japan (the country with the highest national female life expectancy)—Native American men in South Dakota live only 58 years on average, a lifespan akin to that of men in Azerbaijan. Young and middle-aged blacks in high-risk urban areas have mortality risks closer to those in the Russian Federation or parts of sub-Saharan Africa than to those in neighboring white suburbs. Despite efforts to reduce racial and ethnic health inequalities in recent years, the longevity gaps within the U.S. population have remained virtually unchanged for more than two decades.
A recent study headed by Saltonstall professor of population policy Christopher Murray, director of the Harvard Initiative for Global Health, has sought to uncover the major determinants of lifespan disparities among groups of Americans in the hope of identifying more effective interventions. The researchers tracked longevity patterns by place of residence, controlling for race, income, education level, population density, and homicide rates in order to isolate the combinations of factors that contribute to communities’ differential health outcomes. They found dramatic variations in mortality rates across counties that could not be reduced to a single cause such as race or socioeconomic status.
The study authors consolidated their results into “Eight Americas”—eight national subgroups, ranging from best to worst, that capture the geographic and socio-demographic differences in life expectancy observed in the population. America 1, at the top, consists of 10 million Asians, with an average per capita income of $21,566 and an 80 percent high-school completion rate, “living in counties where Pacific Islanders make up less than 40 percent of the total Asian population.” America 8 includes 7.5 million high-risk urban blacks, living in counties with an average per capita income of $14,800, a high-school completion rate of 72 percent, and a probability of homicide death between the ages of 15 and 74 greater than 1.0 percent.
The mid-ranking groups reveal some unexpected disparities. Low-income rural whites living in the northern plains and Dakotas (America 2), for instance, live slightly longer than “Middle America” whites (America 3), who make up the large majority of the population and have the highest average per capita income. Native Americans fare worse when they live in or around reservations in the West (America 5), but rank on a par with mainstream whites when they live elsewhere. Meanwhile, low-income rural whites in Appalachia and the Mississippi valley (America 4) have a life expectancy comparable to that of Mexico and Panama.
The data confirm the importance of place in determining longevity. “It’s not so much the physical environment or the climate that makes a difference, but the social and cultural things that change with place,” Murray says. “Culture largely defines what you eat and whether you exercise, and this has to do with how you were brought up and what your peers do. Once you adopt habits, you tend to keep them.”
Mortality disparities across the eight Americas are most concentrated among young and middle-aged adults and result from a number of chronic diseases and ailments attributable to well-known risk factors, such as using alcohol and tobacco, being overweight or obese, or having elevated blood pressure or problems with cholesterol and glucose. Even in the worst-off urban areas, drugs and violence account for only a small portion of the excess early mortalities. “If you take away deaths from homicide and HIV,” Murray points out, “Baltimore still has one of the worst life expectancies.” The major killers are heart disease, lung disease, diabetes, cirrhosis of the liver, and cancers.
The study’s findings challenge the assumption that universal health insurance alone would significantly reduce the nation’s glaring health inequalities. Variations in health-plan coverage across the eight Americas are in fact small relative to the steep gradient in health outcomes. Education campaigns aimed at altering behaviors are also insufficient, Murray argues. “The exhortation for people to change their lifestyle simply doesn’t work, except among the highly educated and well-to-do,” he says.
The authors call instead for proactive interventions that target the major physiological risks in communities with high mortality. “If I had my influence on policy,” Murray says, “I would put a huge effort into tackling blood pressure, cholesterol, and blood sugar, for which we have effective pharmacological strategies.” America’s longevity gap is unlikely to diminish, he concludes, until “there’s a broader engagement of people living in communities with really poor health, and that gets translated into the political arena.”
Christopher Murray e-mail address:
For “Eight Americas” text, search at: http://medicine.plosjournals.org
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