Background: Smokeless tobacco products, such as chewing tobacco or moist snuff, contain many of the same constituents as tobacco smoke and are also known to cause cancer; however, little attention has been paid to indirect exposure of children to tobacco constituents via parental smokeless tobacco use.
Methods: As part of the California Childhood Leukemia Study, we collected dust samples from 6 residences occupied by smokeless tobacco users, 6 residences occupied by active smokers, and 20 tobacco-free residences. Children's potential for exposure to tobacco constituents was assessed using nicotine concentrations in vacuum dust measured by gas chromatography-mass spectrometry.
Results: Median nicotine concentrations for residences with smokeless tobacco users were significantly greater than median nicotine concentrations for tobacco-free homes and similar to median nicotine concentrations in homes of active smokers. Using generalized estimating equations derived from a multivariable marginal model to adjust for a history of parental smoking, income, residence construction date, and mother's age and race/ethnicity, we found nicotine levels from homes of smokeless tobacco users to be 21-fold higher than nicotine levels from tobacco-free homes. Based on mass balance equations, we hypothesize that nicotine is transferred to floors in homes of smokeless tobacco users primarily as a constituent of tobacco that is spilled or expectorated.
Conclusions: Based on our findings, we conclude that children living with smokeless tobacco users may be exposed to nicotine and other constituents of tobacco via contact with contaminated dust and household surfaces.