Salivary cotinine levels in children presenting with wheezing to an emergency department

We set out to evaluate salivary cotinine concentrations to judge tobacco sm oke exposure among infants and children, and to examine the results in rela tion to age and wheezing. This was a case-control study of wheezing childre n (n = 165) and children without respiratory tract symptoms (n = 106) who w ere enrolled in the Pediatric Emergency Department at the University of Vir ginia. The age range of both wheezing and control patients was 2 months to 16 years. Questionnaires were combined with cotinine assays in saliva to ev aluate exposure to environmental tobacco smoke (ETS) for each child. The prevalence of exposure to one or more smokers at home was high (68%); a nd 43% of the children enrolled were exposed to ETS from their mothers. Acc ording to the questionnaires, and after adjusting for age and race, a wheez ing child in this study was more likely than a control to be exposed to at least one smoker at home (odds ratio = 1.9; 95% CI = 1.1-3.4). However, the odds of exposure to ETS from smoking mothers did not differ significantly between wheezing and control patients, and no significant association was f ound between the presence of wheezing and salivary cotinine levels. Among c hildren exposed to ETS at home, cotinine levels were significantly higher i n saliva from those under the age of two years, and from toddlers aged 2 an d 3 years, compared to values from children over age 4 years. Moreover, the number of smokers in the home strongly influenced cotinine levels from chi ldren under age 4 years. In addition, higher cotinine levels were observed in saliva from children under age 2 years who were exposed to ETS from thei r mothers. Cotinine levels were similar and significantly correlated in pai red samples of saliva and serum from children under 4 years of age (n = 54) , (r = 0.92, P < 0.001). Based on information gathered from questionnaires, the results indicate tha t wheezing children were more likely than controls to be exposed to ETS at home. However, significant differences in ETS exposure between wheezing and control groups with respect to maternal smoke exposure or comparisons of s alivary cotinine levels were not apparent. It was clear that determinations of salivary cotinine for monitoring the prevalence and intensity of househ old smoke exposure in this study were most valuable during the first 4 year s of life. (C) 2000 Wiley-Liss, Inc.