Pollution tied to disease risk in L.A. black women

In a study of more than 4,000 black women in Los Angeles, those who lived in areas with higher levels of traffic-related air pollution were at increased risk of developing diabetes and high blood pressure.

The researchers, led by Patricia Coogan at Boston University, found that black women living in neighborhoods with high levels of nitrogen oxides, pollutants found in traffic exhaust, were 25 percent more likely to develop diabetes and 14 percent more likely to develop hypertension than those living in sections with cleaner air.

Previous research has linked air pollution to health problems such as diabetes, stroke, heart disease and even higher rates of death.

"The public health implications are huge," said Dr. Jiu-Chiuan Chen, who studies the effects of air pollution at the University of Southern California Keck School of Medicine in Los Angeles, especially for black women, who have higher rates of diabetes and high blood pressure than white women. He was not involved in the current work.

Forty-four percent of all black women in the U.S. have high blood pressure and about 11 percent have diabetes compared with 28 percent and roughly seven percent, respectively, of white women, according to the Centers for Disease Control and Prevention.

Evidence suggests that longer-term exposure to air pollutants over years confers higher risks of cardiovascular morbidity and mortality than shorter term exposure. One explanation is that cumulative adverse effects that develop over longer durations lead to the genesis of chronic disease. Preliminary epidemiological and clinical evidence suggest that air pollution may contribute to the development hypertension and type 2 diabetes.

Black Americans also experience higher levels of air pollution than white Americans, according to the study authors.

For their investigation, published in Circulation, the researchers followed participants in the ongoing Black Women's Health Study for 10 years. The women were mainly recruited from subscribers to Essence magazine, and none had diabetes or high blood pressure when the study began in 1995.

Over the course of a decade, 531 women developed high blood pressure and 183 women were diagnosed with diabetes.

The findings on their relative risks for those conditions take into account several other potential influences, including how heavy the women were, whether they smoked and other stressors, including noise levels at participants' homes.

Although researchers measured average pollution levels near participants' homes for only one year of the ten-year study, Coogan told Reuters Health that air pollution patterns remained relatively constant over the entire study period.

While Coogan and her colleagues estimated nitrogen oxide concentrations near participants' homes, they did not account for commuting habits or exposure to air pollution at work. According to the researchers, Americans, on average, spend about 70 percent of their time at home.