Second-hand smoke linked to long-term harm

Results of a new study provide more evidence that exposure to second-hand smoke has long-term adverse effects on respiratory health, and reaffirms the benefits of banning smoking in public places, researchers say.

As part of the European Community Respiratory Health Survey, investigators studied the association between second-hand smoke exposure and the onset of respiratory symptoms or change in lung function by following more than 4,200 adult non-smokers for nine years.

Two hundred eighty three subjects (6.7 percent) had "new" exposure to second-hand smoke during the study, while 713 (17 percent) had ongoing exposure to second-hand smoke.

Results demonstrate "an increased likeliness of developing respiratory symptoms in subjects exposed to passive smoking during the study period," Dr. Christer Janson of Uppsala University in Sweden told Reuters Health.

New exposure to second-hand smoke was associated with a 77 percent higher risk of wheezing and breathlessness compared with unexposed individuals, Janson reported at the Annual Congress of the European Respiratory Society underway in Munich.

The risk of chest tightness at night was 80 percent higher in those with new or recent passive smoke exposure.

The results were similar for those with ongoing exposure to passive smoke. For example, these individuals were 69 percent more likely to wheeze during exertion and more than twice as likely to have a persistent cough during the study.

"This longitudinal study adds further to evidence for a causal relationship between environmental tobacco smoke exposure and respiratory symptoms in adults," Janson and colleagues state in a summary of their meeting presentation.

The good news, Janson told Reuters Health, is that there has been "quite a large decline in exposure to environmental tobacco smoke."

Since the ECRHS began in 1990, the number of non-smokers exposed to second-hand smoke in Europe has fallen by 50 percent, no doubt as a result of measures adopted in many countries to ban or markedly reduce exposure to second-hand cigarette smoke.