Teen Smoking May Increase Breast Cancer Risk

Teenage girls who smoke may be putting themselves at a higher risk for breast cancer, according a new study by Health Canada, the health agency for the Canadian government. The study results, published in the October 5th issue of the British medical journal The Lancet, provide another good reason to discourage smoking among teenage girls.

Women who had started smoking as teenagers -- within five years of beginning menstruation -- and had been pregnant have a significantly higher risk of breast cancer, researchers found after surveying 2000 women in Canada. Likewise, women who smoke heavily (20-plus cigarettes a day for 20 cumulative pack-years or more) and never became pregnant also face high risk for the disease.

However, postmenopausal women who have had at least one full-term pregnancy prior to taking up the habit of smoking are at lower risk than the other two groups.

Investigators theorized that breast cancer tissue could be particularly sensitive to cancer-causing agents during puberty when the breasts are developing.

Prior studies have been unable to establish a link between smoking and breast cancer. And this study, because of the relatively small sample of women, also does not provide definitive proof. The study's authors noted the need for more research into the associations between environmental carcinogens and the risk of breast cancer, especially where the timing of exposure is concerned.