Study Finds Even a Little Cigarette Smoke Harms Airway

A drag from a cigarette now and then can't hurt, right? Wrong, according to a new study that finds even low levels of smoke exposure can cause irreparable damage to cells essential to breathing. The damage occurred among "casual" smokers and even after exposure to secondhand smoke. The initial damage, while not usually severe, can be cumulative and prolonged exposure to tobacco smoke could lead to chronic obstructive pulmonary disease (COPD) and even lung cancer, the researchers reported. "It has been known for a long time that secondhand smoke or smoking occasionally can be risky for your health," said study author Dr. Ronald Crystal.

Just how much a little exposure might damage airway cells hasn't been clear, however. "We found that if we could detect nicotine in the urine we could also detect changes in the genes in the cells lining the airways," said Crystal, who is also chair of the department of genetic medicine at Weill Cornell Medical College. The bottom line: "There is no level of cigarette smoking or exposure to cigarette smoke that does not make the cells in your lungs sick," he said. "If you are an occasional smoker you are still at risk. Don't think that smoking one or two cigarettes a week means you are home free."

As for secondhand smoke, "if you are working in a place where people smoke, either get them to stop or go get another job," Crystal advised. "If you have somebody at home who smokes, send them outside to smoke. Don't be exposed to secondhand smoke." The report is published in the Aug. 20 issue of American Journal of Respiratory and Critical Care Medicine. For the study, Crystal's team recruited 121 people who were nonsmokers, active smokers or low-exposure smokers. To determine who belonged in which group, all participants had their urine tested for levels of nicotine.