Tobacco-specific nitrosamines, hemoglobin adducts and exposure to environmental tobacco smoke

Hemoglobin (Hb) adducts of 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB), a metabolite of two tobacco-specific nitrosamines: 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N’nitrosonornicotine (NNN), were measured in blood samples collected from 47 non-smokers, including 21 cases of lung cancer, enrolled in four centers. Exposure to environmental tobacco smoke (ETS) during the previous year from the spouse and at the workplace was assessed through questionnaire. Non-smokers exposed to ETS had a lower and non-significant level of HPB-Hb adducts than unexposed non-smokers (medians 15.8 and 20.1fmol/g Hb, p-value of the difference 0.32). Adjustment for age, sex, center and lung cancer case-control status had no effect on the results. Our results appear not to support the use of HPB-Hb adduct level as a marker of exposure to ETS in non-smokers. The conclusion drawn is however based on a small number of subjects and might suffer from exposure misclassification.