Science and Health

Secondhand smoke linked to higher diabetes risk

(Agencies)
Updated: 2011-03-11 11:05

NEW YORK - Cigarette smoke is tied to a higher risk of type 2 diabetes, formerly known as adult-onset diabetes, for both smokers and the people around them, a study said.

And the more secondhand smoke people are exposed to, the greater their risk of the disease, which results from insulin resistance -- in which cells fail to use insulin properly -- sometimes combined with an absolute insulin deficiency, according to the study, published in "Diabetes Care."

"Accumulating evidence has identified a positive association between active smoking and the risk of diabetes, but previous studies had limited information on passive smoking or changes in smoking behavior over time," wrote John Forman at Brigham and Women's hospital in Boston, who led the study.

The study followed 100,000 women over 24 years.

In 1982, the women -- all participating in the Nurses Health Study -- provided information about how much time they spent around cigarette smoke. During the next 24 years, about one in 18 women were diagnosed with type 2 diabetes.

Forman and his group found that women who smoked more than two packs a day had the highest odds of developing diabetes, with about 30 of the heavy smokers getting diabetes a year for every 10,000 women in the study, compared to about 25 women who didn't smoke and didn't spend time exposed to other people's cigarette smoke.

The risks were actually higher, though, for ex-smokers and women exposed to second-hand smoke, and in both of these groups, about 39 of every 10,000 women developed diabetes each year.

When variables such as weight, age, and family history of diabetes were taken into account, the ex-smokers had a 12 percent higher risk of diabetes compared to women who were regularly exposed to secondhand smoke.

The potential risks of diabetes from being exposed to secondhand smoke weren't previously known, said David Nathan, who heads the Diabetes Center at Massachusetts General Hospital and is a professor at Harvard Medical School.

"This just reinforces the lesson from a public health point of view that we've been stressing for decades," which is to limit exposure to cigarette smoke said Nathan, who was not involved in the study.

He told Reuters Health that no one knows why smoking and type 2 diabetes are linked, but inflammation may play a role in both, adding that even though the study involved women there was no reason to believe its results would not apply to men as well.