Smoking raises the risk of breast cancer for healthy-weight and overweight women but not for those who are obese, new research suggests.
It’s a first-of-its-kind finding, and even if other studies confirm it, it doesn’t mean that smoking is safe for women who weigh way too much, researchers say.
“Smoking is a strong risk factor for many other diseases other than breast cancer,” including lung cancer and heart disease, said Juhua Luo, a West Virginia University scientist.
She led the study and presented results Sunday at a meeting of the American Association for Cancer Research in Orlando, Fla.
Obesity has long been recognized as a risk factor for breast cancer, but research tying smoking to breast cancer is much weaker. In March, Luo published results of a study that found a 16 percent higher risk of breast cancer among postmenopausal women who smoke or used to smoke versus those who never did.
The 76,628 women were in a government-funded, decades-long study called the Women’s Health Initiative, and 3,378 breast cancer cases occurred.
Luo’s new study looks closer at these same women according to body mass index, a measure of height and weight.
Those who were healthy-weight or merely overweight, with BMIs under 30, were more likely to develop breast cancer if they smoked; the risk was 16 percent higher for those smoking for 10 to 29 years and 25 percent higher for those who smoked 30 to 49 years.