Much research has shown an association between smoking and higher breast cancer risk. A study found that breast cancer risk is higher in women who smoke AND who have a slow-acting form of a particular gene, NAT2.
Slow-acting NAT2 is found in 50% to 60% of white women and 35% to 40% of African American women. The slow-acting form of NAT2 slows the body's ability to get rid of aromatic amines, the cancer-causing substances in cigarette smoke. In this study, women who smoked but DIDN'T have the slow-acting NAT2 gene had the same breast cancer risk as women who didn't smoke.
This study suggests that smoking may not increase breast cancer risk in women who don't have the slow-acting NAT2 gene. But there isn't a routine test for the slow-acting NAT2 gene. Even if you have the fast-acting version of NAT2, smoking is a bad idea. Smoking can harm your heart and lungs and put your overall health at risk.
If you don't smoke, don't start. If you do smoke, get help and find a way to quit. It's tough, but definitely worth it. The American Lung Association offers a free online smoking cessation program. Local chapters of the American Cancer Society offer their Fresh Start program to help people quit smoking. You can also call their "quitline" at 1-800-ACS-2345, to get support and free advice on how to stop smoking from trained counselors.