Research links nicotine, 'pre-diabetes'

WASHINGTON, July 12 (UPI) -- Smoking increases the risk of heart disease and stroke because nicotine builds insulin resistance, U.S. researchers say.

The insulin resistance creates a condition known as "pre-diabetes," in which blood glucose levels are elevated, but not to the point of diabetes, the researchers said at the Endocrine Society's 91st annual meeting in Washington.

Pre-diabetes, the researchers said, leads to a much greater risk of cardiovascular disease.

The researchers -- from Charles Drew University of Medicine and Science in Los Angeles and Western University of Health Sciences in Pomona, Calif. -- also reported they partially reversed this harmful effect of nicotine in mice by treating them with the nicotine antagonist Mecamylamine.

Theodore Friedman, chief of endocrinology at Charles Drew, said the insulin resistance explains why smokers have a high cardiovascular death rate even though smoking causes weight loss, which in other cases protects against heart disease.

"Our results suggest that decreasing insulin resistance may reduce the heart disease seen in smokers," Friedman said in a statement. "We anticipate that in the future, there will be drugs to specifically block the effect of nicotine on insulin resistance."

When smokers become insulin-resistant, their blood glucose levels become higher than normal, but don't reach the level for diabetes.

The study was funded by the National Institutes of Health.