Chapter 5: Biomarkers of Human Exposure to Environmental Tobacco Smoke (ETS)

Involuntary smoking [exposure to secondhand or environmental tobacco smoke (ETS)] is hazardous to the health of non-smokers. Biomonitoring non-smokers for exposure to ETS is important for identifying those at risk and for measuring the effectiveness of tobacco control strategies aimed at reducing exposure. Nicotine and its metabolite cotinine are widely used as biomarkers of exposure to ETS. Their presence in blood, saliva and urine provide reliable indicators of recent exposure (hours to days). Other biomarkers in urine include 4-(methylnitrosamino)-1-(3-pyridinyl)-1-butanone (NNK), a carcinogenic nitrosamine specific to tobacco, and its metabolites. Although the use of urinary biomarkers is widespread, there is also a need for longer-term biomarkers of exposure. Hair, fingernails and toenails sequester nicotine and can provide a biomarker of exposure to ETS over periods of several months. Of particular importance is the monitoring of children's exposure to ETS, including neonatal and prenatal exposure. The tissues and biological matrices already mentioned have utility for this purpose, as well as meconium, breast milk and deciduous teeth. A number of other biomarkers that have sufficient sensitivity and specificity to distinguish smokers from non-smokers, such as proteins adducts and DNA adducts, have given inconsistent results in studies to distinguish non-smokers exposed to ETS from those unexposed.