EXPOSURE OF THE US POPULATION TO ENVIRONMENTAL TOBACCO-SMOKE - THE 3RD NATIONAL-HEALTH AND NUTRITION EXAMINATION SURVEY, 1988 TO 1991

Objective.-To estimate the extent of exposure of the US population to environmental tobacco smoke and the contribution of the home and workp lace environment to environmental tobacco smoke exposure. Design.-Nati onally representative cross-sectional survey including questionnaire i nformation from persons aged 2 months and older (n=16818) and measurem ents of serum cotinine (a metabolite of nicotine) from persons aged 4 years and older (n=10642). Setting/Participants.-Participants in the T hird National Health and Nutrition Examination Survey, October 25, 198 8, to October 21, 1991. Results.-Of US children aged 2 months to 11 ye ars, 43% lived in a home with at least 1 smoker, and 37% of adult non- tobacco users lived in a home with at least 1 smoker or reported envir onmental tobacco smoke exposure at work. Serum cotinine levels indicat ed more widespread exposure to nicotine. Of non-tobacco users, 87.9% h ad detectable levels of serum cotinine, Both the number of smokers in the household and the hours exposed at work were significantly and ind ependently associated (P<.001, multiple regression t test) with increa sed serum cotinine levels. Serum cotinine levels of children, non-Hisp anic blacks, and males indicated that these groups had higher exposure to environmental tobacco smoke. Dietary variables showed no consisten t association with serum cotinine levels, and dietary contribution to serum cotinine level, if any, appeared to be extremely small. Conclusi ons.-The high proportion of the population with detectable serum cotin ine levels indicates widespread exposure to environmental tobacco smok e in the US population, Both the home and workplace environments signi ficantly contribute to environmental tobacco smoke exposure in the Uni ted States.