A study which appeared in a recent edition in the Archives of Internal Medicine indicates that any history of smoking increases a woman's chance of developing breast cancer by six percent. The researchers analyzed the largest sample size in any study involving breast cancer and smoking, according to TheAge.com.au
Tobacco has already been proven to cause lung cancer and at least nine other types of tumors, but the link between breast cancer and smoking has never been fully established. The research drew on the records of the Nurses' Health Study and followed 111,000 women over 30 years.
The study found a six percent increase in risk if a woman has smoked at all during her lifetime, but smoking a pack a day before menopause increases a woman's risk from one in eight to one in 7.5.
"On its own, the impact of smoking on breast cancer is not major, but this adds to the many other damaging effects of tobacco," Walter Willet, Harvard School of Public Health professor, told the news source.
According to BreastCancer.org, one in eight women will develop some form of invasive breast cancer in their lifetime.