Link Found Between Secondhand Smoke and Diabetes

By Catherine Donaldson-Evans Mar 14th 2011 News

Smokers and people exposed to secondhand smoke have a higher chance of getting type 2diabetes than those who aren't around smoke at all, according to new research. And the more you breathe it in, the greater the risk.

Experts say the findings about secondhand smoke's potential role in the risk of diabetes were unexpected.

Lead researcher Dr. John P. Forman of Brigham and Women's Hospital in Boston and his team studied 1982 data from questionnaires given to more than 100,000 women. The respondents were nurses who were part of a larger national survey that stretched over several decades.

They were asked how much time they spent around cigarette smoke and secondhand smoke, Reuters said.

Over the course of the following 24 years, about 1 in 18 of the participants were told they had type 2 diabetes. The National Institutes of Health estimates that 1 in 13 in the United States live with the disease.

The findings, published in the journal Diabetes Care, showed that the nurses who smoked more than two packs of cigarettes a day had the highest risk of getting diabetes. About 30 of the heavy smokers were diagnosed with the disease each year for every 10,000 women in the study. About 25 nonsmokers in 10,000 who were frequently around secondhand smoke got type 2 diabetes, according to the research.

Surprisingly, however, the risks of developing the disease were higher for former smokers and women exposed to secondhand smoke, with about 39 in 10,000 getting diabetes every year.

After the researchers accounted for other potential contributing factors, including age, weight and family history, they saw that the ex-smokers had a 12 percent higher chance of getting diabetes than the participants who routinely breathed in secondhand smoke.

It wasn't clear why a link emerged between type 2 diabetes and smoking, but inflammation in the cardiovascular system and cells is thought to play a part.

Dr. Gerald Bernstein, the director of the Diabetes Management Program at the Friedman Diabetes Institute in New York, said the findings make sense.

"Everything we do that is not good for you creates an inflammatory reaction of some kind," Bernstein told AOL Health. "Among them is cigarette smoke."

But, he said, the number of people at risk for type 2 diabetes is "enormous" to begin with.

"Because so many people are at risk for type 2 diabetes, the probability that a smoker could be next to somebody with that risk could be high," Bernstein said. "It will have an impact on the vascular system. Along with that, it might have an impact on the cells in the pancreas where insulin is produced."

Type 2 diabetes is characterized by the body's inability to process sugar, leading to potentially deadly complications and requiring sufferers to get regular insulin injections. It generally crops up in adulthood and can sometimes be managed with diet and exercise changes.

Dr. David Nathan, the head of the Diabetes Center at Massachusetts General Hospital, said the research doesn't mean smokers should keep up the habit, nor does it mean that women are more susceptible to diabetes than men if they're around cigarette smoke.

"There's no a priori reason to think that this wouldn't apply to men as well," he told Reuters.

The observational, retrospective study didn't establish a cause-and-effect relationship between the disease and smoking, but simply showed that the two seem to be associated.

But that doesn't take away from the study, Bernstein said.

"When you look at people with type 2 diabetes, you will see inflammatory events occurring around the beta cells. [Smoking] could just aggravate that," he told AOL Health. "That's conjecture because it's not proven ... but it's real. And it's not surprising."