When you live or work with a smoker, you inhale the same toxic chemicals that are known to produce cellular changes in the lungs, increasing your risk as much as 20% to 30%, according to the Centers for Disease Control and Prevention. And it’s not just lung cancer. Korean researchers found a significant risk for developing any type of cancer, including breast (by about a quarter), with exposure to second-hand smoke.
Exposure is a matter of degree, says Jacob Sands, M.D., a physician at the Thoracic (Lung) Cancer Treatment Center at Dana-Farber Cancer Institute in Boston. An occasional whiff of a cigarette probably didn’t harm you. But if you live in a state that hasn’t banned smoking in public places (Indiana, Kentucky, Mississippi, South Carolina, Texas, West Virginia, and Wyoming), your exposure may have been the tipping point.