August 2007 - Studying people in their homes and neighborhoods, investigators have found that poor housing conditions contribute to the risk for diabetes in urban, middle-aged African-Americans.
Good housing in an inner-city St. Louis neighborhood (above) contrasted with poor housing and poor conditions in a nearby St. Louis neighborhood.
A team of investigators from Washington University School of Medicine in St. Louis, Indiana University School of Medicine and other institutions conducted the study. They published their findings in the Aug. 15 issue of the American Journal of Epidemiology.
"We looked at several risk factors to see if they could explain why some African-Americans were more likely to develop diabetes," explains Mario Schootman, Ph.D., assistant professor of epidemiology and medicine and chief of the Division of Health Behavior Research at Washington University. "And we found that housing conditions somehow contribute to the development of diabetes."
The study looked at many risk factors for diabetes including weight, smoking, exercise, alcohol use, marital status and education. But when the researchers adjusted for all of those factors, housing conditions still influenced diabetes risk.
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"So far we can't explain why that is," Schootman says. "It could potentially be related to lead. Lead is associated with the development of diabetes, and we know that in some poorer housing conditions, there's likely to be lead exposure. But it also could be related to other, unknown environmental contaminants."
Schootman also says stress might be involved. Individuals who live in poor housing conditions may be more likely to be under stress as a function of where they live. There are known links between stress and diabetes that could help explain the increased incidence of diabetes in this population.
"But a counter-argument against that would be that diabetes risk was associated with housing but not neighborhoods," he says. "We would have expected that if stress was playing a role, the neighborhood conditions also would be involved."
The researchers found that although there was no direct association with neighborhood conditions, sub-standard housing more than doubled diabetes risk. The two neighborhoods studied included a poor, inner-city area and a less-impoverished, suburban area that included several pockets of residents from a variety of socioeconomic backgrounds.
Interviewers spoke to participants in their homes. They gathered data about health status, access to medical care and demographic characteristics, but they also were trained to look for certain things in neighborhoods and houses.
They rated neighborhoods based on noise, air quality and the conditions of houses, streets, yards and sidewalks. Things like broken windows, bad siding on homes, cracks in the sidewalks and nearby industrial sites or traffic noise lowered a neighborhood's rating. Houses were rated based on cleanliness inside of the building and the physical condition of the building's interior and exterior, as well as the condition of the furnishings in the building. Neighborhoods and houses then were classified as fair, poor, good or excellent. Housing included both apartments and single-family homes, and housing conditions rated as fair or poor were associated with increased risks for diabetes.
"It's not clear exactly how housing conditions are exerting this influence," says senior author Douglas K. Miller, M.D., the Richard M. Fairbanks Professor in Aging Research and Regenstrief Institute research scientist at Indiana University School of Medicine. "But it is clear that it won't be possible to reduce disparities in health status among subgroups in the population without understanding how a person's environment can affect that person's health."
This study grew out of a larger health study involving African-Americans. In the original study, researchers looked at several factors responsible for the higher incidence of health problems experienced by later middle-aged and older African-Americans living in St. Louis. That original study gathered data from 998 African-Americans in the St. Louis area who were born between 1936 and 1950.
When that study began, diabetes already was very common in this population. More than 25 percent had the disease at the time initial interviews were conducted. The new study found that over the next three years another 10 percent developed diabetes.
"I think that's a huge finding in and of itself," Schootman says. "Think about how many middle-aged African-Americans live in a place like St. Louis, and if our sample is at all representative of the larger community, you can see that the number of people with diabetes is growing very rapidly over time. I also think it's likely that we would find comparable results if we had done similar research in Detroit or Atlanta or New York City."
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Schootman says more studies will be needed to determine what specifically increased the risk of diabetes as a result of poor housing conditions, but many factors have already been ruled out.
Schootman M, Andresen EM, Wolinsky FD, Malmstrom TK, Miller JP, Yan Y, Miller DK. The effect of adverse housing and neighborhood conditions on the development of diabetes mellitus among middle-aged African Americans. American Journal of Epidemiology; vol. 166 (4), pp. 379-387, Aug. 15, 2007.
This research was funded by the National Institutes of Health.
Source: National Institutes of Health