Compared to postmenopausal women who had never smoked, breast cancer risk increased by 9% among former smokers and by 16% among current smokers, according to a new study published online March 1 in the British Medical Journal.
Dr. Karen Margolis, a senior clinical investigator with the HealthPartners Research Foundation, and colleagues analyzed data for nearly 80,000 women between the ages of 50 and 79. In total, they identified 3,250 cases of invasive breast cancer during an average of 10 years of follow-up.
The researchers found that the highest risk was among current smokers with the highest intensity and duration of smoking, and among women who began smoking during the teenage years or before their first full-term pregnancy. Among former smokers, the increased risk of breast cancer persisted for up to 20 years following smoking cessation.
