FACTORS DETERMINING EXPOSURE TO PASSIVE SMOKING IN YOUNG-ADULTS LIVING AT HOME - QUANTITATIVE-ANALYSIS USING SALIVA COTININE CONCENTRATIONS

Saliva cotinine concentrations were used to examine determinants of exposure to environmental tobacco smoke in 393 non-smoking students (age range 16-19 years) attending a sixth form college and living at home. Average concentrations were low (median 0.60 ng/ml), reflecting partly the warm weather at the time of the survey and partly the predominantly middle class sample. Despite this, cotinine levels were strongly related to the extent of self-reported passive smoking in the past three days (medians 0.30, 0.60, 0.90 and 1.35 ng/ml in those reporting 'None at all','A little', 'Some' and 'A lot' respectively, p < 0.0001). Individual sources of environmental tobacco smoke identified were smoking by mothers (p < 0.0001), by fathers (p < 0.01), and exposure at college (p < 0.001) and when out in the evenings (p < 0.001). The results indicate that exposure outside the home may become of equal or greater importance than family smoking in determining the overall passive smoking dose received by this age group.