Racial disparities in diabetes prevalence linked to living conditions

The higher incidence of diabetes among African Americans when compared to whites may have more to do with living conditions than genetics, according to a study led by researchers at the Johns Hopkins Bloomberg School of Public Health. The study, available online in advance of publication in the October 2009 edition of the Journal of General Internal Medicine, found that when African Americans and whites live in similar environments and have similar incomes, their diabetes rates are similar, which contrasts with the fact that nationally diabetes is more prevalent among African Americans than whites. Researchers from the Hopkins Center for Health Disparities Solutions and Case Western Reserve University School of Medicine compared data from the 2003 National Health Interview Survey (NHIS) with the Exploring Health Disparities in Integrated Communities Southwest Baltimore (EHDIC-SWB) Study. The Baltimore study was conducted in a racially integrated urban community without race differences in socioeconomic status.

In recent decades the United States has seen a sharp increase in diabetes prevalence, with African Americans having a considerably higher occurrence of type 2 diabetes and other related complications compared to whites.

"While we often hear media reports of genes that account for race differences in health outcomes, genes are but one of many factors that lead to the major health conditions that account for most deaths in the United States," said Thomas LaVeist, PhD, director of the Hopkins Center for Health Disparities Solutions and lead author of the study.

Some researchers have speculated that disparities in diabetes prevalence are the result of genetic differences between race groups. However, LaVeist noted that those previous studies were based on national data where African Americans and whites tend to live in separate communities with different levels of exposure to health risks. The EHDIC-SWB study accounts for racial differences in socioeconomic and environmental risk exposures to determine if the diabetes race disparity reported in national data is similar when black and white Americans live under comparable conditions.

"I don't mean to suggest that genetics play no role in race differences in health, but before we can conclude that health disparities are mainly a matter of genetics we need to first identify a gene, polymorphism or gene mutation that exists in one race group and not others. And when that gene is found we need to then demonstrate that that gene is also associated with diabetes," LaVeist said. "On the other hand, there is overwhelming evidence that behavior, medical care and the environment are huge drivers of race differences in health. It seems more likely that the answer to health disparities will be found among these factors."

Researchers in this study found that within their sample of racially integrated communities without race differences in socioeconomic and environmental factors, prevalence estimates of diabetes are similar between African Americans and whites. According to the study, "Previous research has demonstrated that when African Americans and whites access similar health care facilities their health care outcomes are more similar."

The study's authors said their findings support the need for future health disparities research and creative approaches to examining health disparities within samples that account for socioeconomic and social environmental factors.

Source: Johns Hopkins University Bloomberg School of Public Health