Study: Smoking shortens life span by at least 10 years

People who smoke take at least 10 years off their life expectancy, a new study has found.

On the other hand, those who kick the habit before age 40 reduce the excess risk of death associated with continued smoking by about 90%, according to the study in Thursday's New England Journal of Medicine.

"Smoking is the No. 1 preventable cause of death in the U.S.," says Tim McAfee, a co-author of the study. "We need to do more to educate the American people about these findings," adds McAfee, director of the Office on Smoking and Health at the Centers for Disease Control and Prevention.

The study examined data from the U.S. National Health Interview Survey between 1997 and 2004.

Women who smoke now die at a similar rate for men, the study also found. Previous research from the 1980s showed that women were less affected.

"Women now lose about 11 years of life expectancy if they smoke," McAfee says. "Men lose about 12 years." He adds that it is presumed that women's smoking patterns are now more similar to men's in terms of picking up the habit at younger ages and smoking a larger number of cigarettes.

McAfee says the study has global implications because most of the world's 1.3 billion smokers live in low- and middle-income countries, where cessation is less common.