MEASURING EXPOSURE TO ENVIRONMENTAL TOBACCO-SMOKE IN STUDIES OF ACUTEHEALTH-EFFECTS

The relations among three methods of measuring exposure to environment al tobacco smoke questionnaires, urinary cotinine, and a passive monit or for ambient nicotine, were investigated in a study of 48 children i n Minnesota in 1989. Subjects were all under 2 years of age and did no t attend day care. Passive nicotine monitors were placed in the activi ty room and the child's bedroom for 1 week, urine samples were collect ed at the beginning and end of the week for cotinine analysis, and a d etailed questionnaire concerning cigarette smoking was administered at the end of the week. These same measures were obtained weekly for 8 w eeks for 22 of the children. Among households with smokers, concentrat ions of ambient nicotine and urinary cotinine were lowest when the fat her smoked, intermediate when the mother smoked, and highest when both parents smoked. Activity room concentrations were highly correlated w ith both urinary cotinine (r = 0.81) and the total number of cigarette s smoked in the house (r = 0.86). Regression equations indicated that knowing who smoked in the house was a more important predictor of ambi ent nicotine than knowing the amount smoked. Both urinary cotinine and ambient nicotine demonstrated variability over time, although ambient nicotine was less variable. In addition, 100% of possible ambient nic otine samples were collected in contrast to 80% of urine samples. The results of the study suggest that both urinary cotinine and ambient ni cotine provide better information about the exposure of young children to environmental tobacco smoke than questionnaire data alone, and tha t ambient nicotine may be the more useful in this population based on its greater stability and ease of collection.