as much as smoking cigarettes, U-M study shows.
Living in a city is risky, especially for men, according to a University of Michigan study of 3,617 adults published in the December issue of the American Journal of Public Health.
During the seven-and-half-year period of the study, men who lived in urban areas were 62 percent more likely to die than men who lived in suburbs, small towns or rural areas, the researchers found. They controlled for age, health, income, education, and many other potential predictors of mortality.
"The excess mortality risk among men residing in cities rivals that of cigarette smoking, social isolation, low income and other major psychosocial risk factors for mortality," says sociologist James S. House, first author of the study. House is director of the Survey Research Center at the U-M Institute for Social Research, the world's largest academic survey and research organization.
For the study, the first to estimate the prospective impact of urban residence on mortality in a fully representative national sample and to control for a wide range of confounding factors, the researchers first interviewed 3,617 adults over the age of 25 in 1986. Overall, 24 percent of the sample lived in cities, 47 percent lived in suburbs, and 29 percent lived in small towns or rural areas.
They collected information about age, sex, race, marital and socioeconomic status and multiple self-reported measures of health and health behaviors including smoking, drinking, and physical exercise.
Over the next seven and a half years, the researchers followed the sample through follow-up surveys. By 1994, 542 had died. They obtained death certificates for verification, and to determine the cause of death. Then, after controlling for confounding variables such as health at the time the study started, they calculated how place of residence was linked with mortality, and with death from specific causes, for men, women, Blacks, non-Blacks and those over and under the age of 65.
Living in a city, they found, carried an excess hazard of mortality only for men under the age of 65, and for white men in particular. For Black men, they found, living in a suburb was linked with a risk of death as great as or greater than living in a city.
"Recent research indicates that the majority of Blacks live in suburbs that are no better (or even worse) socioeconomically than the nearby central cities," notes House. "Even among Blacks living in more affluent or racially integrated suburbs, stress linked to race and racism may add to or compound other ambient stresses of life in urban areas."
The risk of city residence was not linked to specific urban areas or types of cities, the researchers found. It extended across most types of death, but was most significant for infections and tumors. "Elevated levels of tumor deaths suggest the influence of physical, chemical, and biological exposures in urban areas, perhaps potentiated by immunosuppressive effects of the ambient psychosocial stresses of urban life," the researchers note.
"Living in cities also involves potentially stressful levels of noise, sensory stimulation and overload, interpersonal relations and conflict, and vigilance against hazards ranging from crime to accidents," they add. In addition, city residents may also have fewer adaptive resources for dealing with such stresses, particularly social relations and supports.
As to why cities are particularly toxic to men, House can only guess. "Men could have some greater exposure to whatever is hazardous in the urban environment," he speculates. "Men may spend more time outside of the house, and may spend that time in work or other environments that are risky to their health. Or, it could be that women might have some social, psychological, or biological resources that buffer or protect them from the hazard of city life."
Established in 1948, the Institute for Social Research (ISR) is among the world's oldest survey research organizations, and a world leader in the development and application of social science methodology. ISR conducts some of the most widely-cited studies in the nation, including the Survey of Consumer Attitudes, the National Election Studies, the Monitoring the Future Study, the Panel Study of Income Dynamics, the Health and Retirement Study, and the National Survey of Black Americans. ISR researchers also collaborate with social scientists in more than 60 nations on the World Values Surveys and other projects, and the Institute has established formal ties with universities in Poland, China, and South Africa. Visit the ISR Web site at www.isr.umich.edu for more information.
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Journal
American Journal of Public Health