Respiratory symptoms and lung function in relation to passive smoking: a comparative study of American and French women.

Results are reported from a parallel analysis of the association of passive smoking with respiratory symptoms and lung function (FEV1, FVC and FEV1/FVC) in 2220 US and 3855 French women from the general population examined over the same time period using similar methods. Age, city, educational level, occupational exposure and height (for lung function) were taken into account. In the US survey, being a never smoker married to a current or former smoker was significantly associated only with wheezing compared to being a true never smoker. A borderline significant association between passive smoking and dyspnoea was observed among women older than 40 in the French survey. No association was observed with cough or phlegm production. Passive smoking was significantly related to lower FVC and FEV1 values among French women 40 years or more, even among those without a history of wheeze or asthma. However, even among US women older than 40 years of age, there was no significant association between passive smoking and level of lung function. Better housing conditions, higher divorce rates, more frequent exposure to passive smoking in childhood, and different selection factors for active smoking in the US compared to France might explain the lack of association of current spousal smoking habits with lower lung function in American women.