Involuntary Smoking and Urinary Cotinine

Abstract

In epidemiological studies, involuntary smokers are generally classified using familial smoking habits based on questionnaires. However, this method is liable to give rise to misclassifications. Currently, the most promising method for estimating ETS exposure levels may be the measurement of cotinine in urine or serum. Therefore we compared questionnaires and cotinine levels in urine for the assessment of ETS exposure levels. Cotinine in urine was measured using an improved method of gas chromatography with a capillary column and flame thermionic detector. Subjects were 34 primary school children and their mothers. Data and urine samples were collected in February (winter) and July (summer) 1986. Urinary cotinine levels in both mothers and children were higher in winter than in summer. Correlation coefficients between number of cigarettes smoked by the family members in the same room and cotinine levels in winter in mothers and children were 0.820 and 0.626, respectively. It was suggested that the estimation of ETS exposure levels may be improved by asking for the number of cigarettes smoked at home per day.