​Cigarette smoking may up breast cancer risk in women.
This study explored the relationship between active smoking and the tendency of developing breast cancer in women. A group of US scientists analyzed the lifestyle and clinical data of more than 70,000 women who participated in the American Cancer Society's Cancer Prevention Study II and 14 other studies.
The research team found a higher incidence of breast cancer in current and former smokers than in never smokers. The positive association between cigarette smoking and breast cancer was found to be stronger in women who started smoking before their first birth. These results strongly suggest that cigarette smoking may stimulate the formation of cancerous cells and tumors in the breast.