JAMA Logo Polycyclic aromatic hydrocarbons, aromatic amines and N-nitrosamines are known as potential human breast carcinogens. Apparently, these carcinogens are present in tobacco smoke, hence increased the chances of developing breast cancer. Investigators now claim that those smoking before menopause, particularly prior to giving birth have a modest raise in the risk of being diagnosed with breast cancer.

At the time of the study, authors thoroughly assessed the records of 111,140 women from 1976 to 2006 for active smoking and 36,017 women from 1982 to 2006 for passive smoking. Around 8,772 breast cancer cases were registered by the study follow-up. Breast cancer development was supposedly linked with a higher quantity of current and past smoking, smoking for a longer period of time, younger age at smoking initiation and more pack-years of smoking.

Scientists share, “In the present study, we created an index of active smoking that integrates quantity, age at which one started smoking and duration of smoking. The results suggested that, although an elevated risk for light smokers and moderate smokers was not apparent, heavy smokers who started smoking early in life, smoked for a long duration and smoked a high quantity were at the highest risk of breast cancer, supporting an independent and additive effect from various smoking measures on breast carcinogenesis.”

Fei Xue, M.D., Sc.D., of Brigham and Woman’s Hospital and Harvard Medical School, Boston, and colleagues observed that breast cancer risk was positively related to smoking before menopause. It was concluded that smoking after menopause can possibly decline the threat of breast cancer. However, this reduction in breast cancer risk appears very insignificant. It is predicted that an antiestrogenic effect of smoking in postmenopausal women can decrease their already low endogenous estrogen levels. Never smoking and passive smoking in childhood or adulthood may not be involved in raising breast cancer risk. Experts believe that passive smoking through parents or work place colleagues is not associated with breast cancer risk.

The study was published in the January 24 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.