Development of epidemiologic tools for measuring environmental tobacco smoke exposure

In this study, current weekly environmental tobacco smoke exposure was measured in 53 nonsmoking volunteers. Three exposure assessment tools were used: a passive nicotine monitor; a baseline questionnaire; and a seven-day diary. Exposure episodes were recorded according to location, space ventilation characteristics, number of smokers, number of hours, proximity of smokers, and intensity of environmental tobacco smoke. In Phase 1, various formulas for an environmental tobacco smoke exposure index based on the questionnaires and diaries of 19 volunteers were tested against the nicotine (microgram) collected by the monitor to determine the index providing the best fit. The formula referred to as the hsp (hours x smokers x proximity) index provided the best correlation with log nicotine levels for the questionnaire (r2 = 0.829) and the diary (r2 = 0.900). All episodes of environmental tobacco smoke exposure in all locations were summed over seven days. Each exposure received a weighting according to number of hours (h), number of smokers (s) and proximity of smokers (p). In Phase 2, the hsp index was refined to adjust for social situations with many smokers. In Phase 3, the refined hsp index (hsp*) was used to predict cumulative weekly nicotine collected on monitors worn by 33 new volunteers. All 33 nicotine measurements in the validation set were closely predicted by a simple linear regression model using log nicotine and the hsp* index (r2 = 0.98). The results of this study indicate that relatively simple questionnaires and diaries can be developed to assess current environmental tobacco smoke exposure for epidemiologic studies.