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According to a report published in the Archives of Internal Medicine, women who smoke before having children are at increased risk of developing breast cancer. Women have greater odds for breast cancer if they smoke at any time before menopause, but this is particularly apparent if they began smoking before they became a parent.
All together, 111,140 women’s health records dated from 1976-2006 were studied. The women had taken part in the Nurse’s Health Study and their records were checked for active smoking. An additional 36,017 women’s records dated from 1982-2006 were checked for passive smoking.
From these numbers, 8,772 cases of breast cancer developed. Cases occurred in women with a higher quantity of past and current smoking, those who had been smoking for longer periods of time and those who were young when they started smoking.
When researchers looked at passive smoking in childhood, they didn’t find the same increase in breast cancers. Likewise, passive smoking in adulthood didn’t increase the risk.
It is important for the medical community to research the causes of breast cancer because it is the most common form of female cancer worldwide. Tobacco contains lots of breast cancer carcinogens including polycyclic aromatic hydrocarbons, aromatic amines and N-nitrosamines.
"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 wrote.
"This difference suggests an antiestrogenic effect of smoking among postmenopausal women that may further reduce their already low endogenous estrogen levels. In the present study, we created an index of active smoking that integrates quantity, age at which one started smoking and duration of smoking.