FRIDAY, Sept. 12, 2014 (HealthDay News) -- Older people exposed to high levels of black carbon -- the fine particle air pollution from traffic -- may have increased levels of leptin, a hormone linked to obesity, diabetes and heart disease, a new study suggests.
Although the research doesn't establish a cause-and-effect relationship between black carbon exposure and leptin levels, the study authors said their findings could help explain the association between traffic-related air pollution and the risk for heart disease.
"If confirmed, these findings support the emerging evidence suggesting that certain sources of traffic pollution may be associated with adverse cardiometabolic effects," the researchers wrote. "Cardiometabolic" refers to heart disease, stroke and diabetes.
In conducting the study, the investigators measured levels of leptin in the blood of 765 older adults living in Boston. The researchers examined the association between this hormone and the participants' exposure to black carbon.
The study, led by Gregory Wellenius of Brown University, revealed a strong link between exposure to black carbon and leptin levels. Those with the greatest exposure to black carbon had lower incomes and higher rates of high blood pressure and diabetes, the researchers noted. These people were also less likely to be white.
Even after taking these differences into account, leptin levels were 27 percent higher for older people with the greatest exposure to black carbon, according to the findings published in the September issue of the Journal of Occupational and Environmental Medicine.
There was no association, however, between leptin levels and the distance from the participants' homes to a major road, the study authors said in a journal news release. The researchers concluded that the study participants' exposure to black carbon was the result of a wide range of roads situated near their homes.
The U.S. Environmental Protection Agency has more about the health effects of air pollution.