In a recent study published by the British Medical Journal, U.S researchers collected data on nearly 80,000 women ages 50 to 79. The women were asked about their smoking habits at home and at work.
They found that women who smoked or who were exposed to secondhand smoke had a 16 percent increased risk of developing breast cancer.
Earlier studies found little or no connection between breast cancer and smoking. But, as more women smokers reach menopause, the connection may be surfacing for the very first time, researchers noted.
They say these findings merit further studies.
The Associated Press contributed to this story.