Breast Cancer Risk Increases With Exposure to Cigarette Smoke: Study

Postmenopausal women who smoke or used to smoke are more likely to develop breast cancer, according to a study in the British Medical Journal published on March 1, and there is even a link between breast cancer and passive smoking, in women exposed to environmental cigarette smoke as children or adults.

A group of American researchers analyzed data of almost 80,000 women, aged 50 to 79, collected at 40 clinical centers in the United States, including details of smoking habits, such as the age they started or quit and the number of cigarettes smoked per day.

Information on passive smoking was also gathered, for example exposure at work, home, and social settings, both as a child and adult.

The team found that 3,250 of these postmenopausal women developed breast cancer within the 10-year study period. There was an elevated risk of breast cancer of 9 percent in former smokers and 16 percent in current smokers, especially in those women who smoked more cigarettes per day over a longer duration and from an early age.

“Among former smokers, the time since quitting smoking was significantly inversely associated with breast cancer risk, and it took up to 20 years for a former smoker’s risk to return to baseline,” the authors wrote in the study.

There is a suggestive association between breast cancer and extensive passive smoking, but further research is required, the team said.

“Finally, we observed a 32 percent excess risk of breast cancer associated with the most extensive exposure to passive smoking among women who had never been active smokers,” the researchers stated in the study.

“Our findings highlight the need for interventions to prevent initiation of smoking, especially at an early age, and to encourage smoking cessation at all ages.”