LUNG-FUNCTION IN CHILDREN AND ADOLESCENTS WITH OCCASIONAL EXPOSURE TOENVIRONMENTAL TOBACCO-SMOKE

We investigated the effects of occasional exposure to environmental to bacco smoke (ETS) on lung function in children. A total of 317 healthy 12- to 15-yr-old nonsmoking children and adolescents, living in house holds in which none of the adults were active smokers, were selected f or the present analysis. The urinary cotinine:creatinine ratio (CCR) w as taken as the biologic indicator of exposure, and children were clas sified according to CCR quartiles. The ratio between FEV(1) and FVC (F EV(1)/FVC) and both early (peak expiratory flow [PEF]) and midexpirato ry flow rates (FEF(25-75)) were lower in children with higher CCR valu es. In percent terms, the decrease in adjusted lung function for child ren belonging to the second, third, and fourth quartiles in comparison with those in the first quartile was -1.37, -2.12, and -1.94 for FEV( 1)/FVC (p for trend = 0.012); 0.98, -3.31, and -4.54 for PEF (p for tr end = 0.024); and -0.05, -4.85, and -6.13 for FEF(25-75) (p for trend = 0.022), respectively. The effects remained significant when possible confounding by father's education and urinary creatinine level had be en taken into account, and when children whose parents' smoking status may have been misclassified were excluded. This study suggests an adv erse effect on lung function from even low-level exposure to ETS among nonsmoking children living with reportedly nonsmoking parents.