Study leader Patricia Coogan of Boston University School of Public Health and the Slone Epidemiology Center said it is well established that air pollution increases the risks of acute cardiovascular events such as stroke and myocardial infarction.
Coogan and colleagues assessed the risks of incident hypertension and diabetes associated with exposure to nitrogen oxides and particulate matter -- indicators of traffic-related air pollution -- in a study of approximately 4,000 African-American women living in Los Angeles.
From 1995 to 2005, 531 incident cases of hypertension and 183 incident cases of diabetes occurred among the participants, the researchers said.
The study, published in the journal Circulation, found risk of diabetes increased by 24 percent and the risk of hypertension by 11 percent for each 12 parts per billion increase in exposure to nitrogen oxides. There also were suggestive increases in risks of both diseases associated with exposure to particulates but the evidence for this was weaker than for nitrogen oxide, Coogan said.
"A link between air pollution and the risks of diabetes and hypertension is of particular importance to
African-American women, because the incidence of both conditions is almost twice as high in black women as in white women and African-Americans live in more highly polluted areas than white Americans," Coogan said.