Study: Active Smoking Increases Risk of Breast Cancer in Women

Active smoking appears to play a larger role in the development of breast cancer than previously thought, according to a report in the Journal of the National Cancer Institute.

In a study of 2,005 California women diagnosed with invasive breast cancer between 1996 and 2000, the incidence of breast cancer among current smokers was approximately 30 percent greater than that among women who had never smoked.

Further analysis showed an increased breast cancer risk for women who started smoking before age 20, who began smoking at least 5 years before their first full-term pregnancy, who had a longer duration of smoking or who smoked 20 or more cigarettes per day.

But the researchers found no statistically significant increase in breast cancer risk among former smokers, and said there was no evidence of a link between passive smoking exposure and breast cancer risk.

"Exposures to tobacco smoke, if causally related to breast cancer, could offer one of the few available modifiable avenues for preventing this disease," the researchers concluded.

Other Sources: Journal of the National Cancer Institute