Smoking may be associated with increased risk of breast cancer

CHICAGO — Smoking before menopause, especially prior to giving birth, may be associated with a modest increase in the risk of developing breast cancer, according to a report in the Jan. 24 issue of Archives of Internal Medicine.

“Smoking before menopause was positively associated with breast cancer risk, and there were hints from our results that smoking after menopause might be associated with a slightly decreased breast cancer risk,” the authors suggested. “This difference suggests an antiestrogenic effect of smoking among postmenopausal women that may further reduce their already-low endogenous estrogen levels.”

Conversely, never smoking and passive smoking in childhood or adulthood were not associated with an increase in breast cancer risk. Exposure to parents who smoked while living in the same house, passive smoking while at work or at home and the number of years living with someone who smoked were not related to increased risk of breast cancer after adjusting for other possible factors.