RESPIRATORY SYMPTOMS AND LUNG-FUNCTION EFFECTS OF DOMESTIC EXPOSURE TO TOBACCO-SMOKE AND COOKING BY GAS IN NONSMOKING WOMEN IN SINGAPORE

Study objectives-To investigate the effects of passive exposure to tob acco smoke and gas cooking at home on respiratory symptoms and lung fu nction of non-smoking women. Setting-Evidence on the effects of passiv e smoking and exposure to nitrogen dioxide from gas cooking on the res piratory health of adults is limited and variable. Over 97% of women i n Singapore do not smoke, and a principal source of indoor air polluti on for housewives is passive smoking and gas cooking. Design-This was a cross sectional (prevalence) study of a population based sample of 2 868 adults aged 20 to 74 years in Singapore. A structured questionnair e administered by trained interviewers was used to collect data on pas sive smoking, gas cooking, respiratory symptoms, and other relevant va riables. Passive smoking was defined as exposure to cigarette smoke fr om one or more members of the household who had ever smoked. Gas cooki ng was defined in terms of the weekly frequency of gas cooking, as wel l as the frequency with which the respondent's kitchen was filled with heavy cooking fumes (rarely, occasionally, often). Forced expiratory volume in one second (FEV1) was measured by using a portable Micro-spi rometer. Multivariate analyses were used to estimate relative odds of association for respiratory symptoms and FEV1 effect, with adjustment for potential confounding variables. Participants-Of a total of 1438 w omen in the sample, 1282 women who had never smoked provided questionn aire data and 1008 women provided acceptable readings of FEV1 for anal ysis. Main results-Passive smoking was significantly associated with g reater relative odds of usual or chronic cough and phlegm, wheezing, a nd breathlessness on exertion, as well as lower FEV,. Greater relative odds of respiratory symptoms were also associated with the weekly fre quency of gas cooking, although these results were statistically insig nificant. Chronic cough and phlegm and breathlessness on exertion, how ever, were significantly associated with the frequency with which the kitchen was filled with heavy cooking fumes. A lower FEV1 was found in women who cooked frequently (more than thrice a week). Conclusion-Dom estic exposure to cigarette smoke and gas cooking is associated with i ncreased risks of respiratory symptoms and impairment of lung function in non-smoking women in Singapore.