Questionnaire and hair measurement of exposure to tobacco smoke

To assess the relation between nicotine and cotinine levels in hair and rep orted exposure to environmental tobacco smoke (ETS), hair samples from 112 children (aged 3 months to 10 years) and 76 of their mothers were analyzed and information on the smoking habits of household adults in the preceding 6 months recorded. It was found that the levels of nicotine in children's h air were related to the number of smokers in the house, and increased with the total number of cigarettes smoked by all household adults (P<0.0001). I n a multiple regression analysis, mother's smoking was much more a contribu tor to children's nicotine levels than smoking by the father or other house hold adults. Cotinine levels were less strongly associated with reported ET S exposure than nicotine. There was a strong correlation between nicotine h air levels in children and mothers (r(s) =0.7, P<0.0001). However, nicotine levels in the hair of active smokers were not correlated with the reported number of cigarettes they smoked per day. In this population, there was a consistent relation between exposure to ETS (assessed by questionnaire) and dose (as measured by nicotine in hair). We conclude that hair nicotine lev els rather than hair cotinine levels provide an informative and objective m easure of ETS exposure. The number of cigarettes smoked by active smokers m ay not be an accurate measure of the total nicotine levels in their bodies.