Exposure to air pollution for just a month or two may still be enough to increase the risk of developing diabetes, especially for obese people, a recent U.S. study suggests.
Researchers studied more than 1,000 Mexican-Americans living in southern California and found short-term exposure to contaminated air was linked to an increased risk of high cholesterol and impaired processing of blood sugar - risk factors for diabetes.
Scientists aren't exactly sure how air pollution might lead to diabetes.
It's possible that air pollution causes inflammation in the body, which triggers a chain reaction that makes it harder for people to process blood sugar, said senior study author Dr. Frank Gilliland, director of the Southern California Environmental Health Sciences Center and researcher at the Keck School of Medicine at the University of Southern California in Los Angeles.
Some previous research has linked air pollution from traffic and other sources to an increased risk of type 2, or adult-onset, diabetes, which happens when the body can't properly use or make enough of the hormone insulin to convert blood sugar into energy. But few tests have been done in humans, the researchers note in the journal Diabetes Care.
For the current study, Gilliland and colleagues examined concentrations of ozone, an unstable form of oxygen produced when various types of traffic and industrial pollution react with sunlight; nitrogen dioxide, a byproduct of fossil fuel combustion that can contribute to smog; and so-called PM 2.5, a mixture of solid particles and liquid droplets smaller than 2.5 micrometers in diameter that can include dust, dirt, soot and smoke.
