(Ivanhoe Newswire) -- There is more proof that second-hand smoke can make non-smokers sick.

Over 11 years, researchers in Switzerland studied 1,661 people who had never smoked. They report inhaling environmental tobacco smoke (ETS) can cause otherwise healthy adults to develop chronic breathing problems.

Results reveal a strong association between exposure to ETS and coughing. In people who already have a hard time breathing because of narrow airways -- like asthma patients -- the study suggests a link between ETS and wheezing, coughing, shortness of breath, and chronic bronchitis. Researchers say patients with narrow airways who are exposed to ETS often are particularly at risk for developing early-onset chronic respiratory disease.

"Indirect evidence derived from smokers shows that airway responsiveness increases the risk to develop cough, phlegm, dyspnea (shortness of breath), and chronic bronchitis," reports lead author Margaret W. Gerbase, Ph.D., from the University Hospitals of Geneva in Switzerland. "Cessation of smoking leads to remission of symptoms and improvement in airway hyper-reactivity."

The researchers conclude the study results support the need for policies that protect all non-smokers from the detrimental effects of environmental tobacco smoke.

SOURCE: American Journal of Respiratory and Critical Care Medicine, 2006;174:1125-1131