PASSIVE SMOKING AND RISK OF PULMONARY TUBERCULOSIS IN CHILDREN IMMEDIATELY FOLLOWING INFECTION - A CASE-CONTROL STUDY

Setting: Passive smoking-related respiratory disorders in children. Ob jectives: To assess the effect of passive smoking on the development o f active pulmonary tuberculosis (PTB) in children immediately followin g infection by Mycobacterium tuberculosis within the family. Design: A n unmatched case-control study in which 93 contacts who became cases ( active PTB diagnosed) and 95 contacts who did not became cases (tuberc ulin-positive children without evidence of active disease) were includ ed. All were household contacts of a new case of pulmonary bacillary t uberculosis. Smoking habits were investigated by a questionnaire. Urin ary cotinine was analysed. Odds Ratio (OR) was adjusted for age and so cio-economic status using multiple logistic regression analysis. Resul ts: Passive smoking was a risk factor for PTB (OR: 5.29; 95% confidenc e interval (CI): 2.33-12.82; P < 0.00005). The adjusted OR was 5.39 (9 5% CI: 2.44-11.91; P < 0.00001). The risk increased when contacts were passive smokers both at home and outside the home within the family ( OR: 6.35; 95% CI: 3.20, 12.72; P < 0.00001). Contacts 0-4 and 5-9 year s old showed a significantly higher risk than those aged greater than or equal to 10. There was a dose-response relationship between the ris k of developing active PTB immediately following infection and the num ber of cigarettes smoked daily by the household adults (P < 0.001). Me an (SD) urinary continine detectable concentrations (ng/ml) were diffe rent between disease contacts (119.46 [68.61]) and non diseased contac ts (91.87 [73.10]). The difference was statistically significant (P < 0.001). Conclusions: Passive exposure to tobacco smoke in children was associated with an increased risk of developing pulmonary tuberculosi s immediately following infection. This is an association of great con cern requiring health education programmes and antitobacco medical adv ice.