TUESDAY, Jan. 6, 2004 (HealthDayNews) -- Smoking increases a woman's chance of getting breast cancer, says a study in the Jan. 7 issue of the Journal of the National Cancer Institute.
Researchers found the incidence of breast cancer was about 30 percent higher in current smokers than among women who had never smoked.
The study by the California Department of Health Services involved 2,005 women who were diagnosed with invasive breast cancer between 1996 and 2000.
Looking more closely at smokers, the researchers also found an increased breast cancer risk for women who started smoking before age 20, who began smoking at least five years before their first full-term pregnancy, and who had a longer duration of smoking or who smoked at least 20 cigarettes per day.
There was no statistically significant increase in breast cancer risk among former smokers, and there was no evidence of a link between passive smoking exposure and breast cancer risk.
Here's where you can learn more about breast cancer.