A newly published study in Nicotine & Tobacco Research found that young children from low-income, rural homes could be at a higher risk of exposure to second- and thirdhand cigarette smoke than previously reported. Secondhand smoke is smoke in the air that comes from a lit tobacco product, and thirdhand smoke is smoke residue that settles into floors, furniture and clothing.
The study, which was supported by the National Institutes of Health, analyzed data from the Family Life Project, an ongoing longitudinal study of rural poverty involving families in six rural counties of Pennsylvania and North Carolina who delivered a child between September 2003 and August 2004. Researchers for the tobacco study measured cotinine levels in the saliva of 1,218 children from the FLP at ages 6,15, 24, and 48 months; cotinine is a biomarker of tobacco exposure. About 63 percent of the children in the study had detectable levels of cotinine, and about 12 percent of the children had saliva with at least 12 nanograms per millimeter of cotinine, as much as one would expect to find in an active adult smoker.
“Greater exposure was associated with lower income, less education, more residential instability, and more instability in adult occupants in the home, whereas time spent in center-based day care was associated with lower exposure,” the researchers write.
Greater residential instability correlates with higher smoke exposure because thirdhand smoke lingers, so a nonsmoking family that moves into a home once occupied by a smoker will likely be exposed to thirdhand smoke. Poverty is associated with frequent moves, which the researchers hypothesize could increase such children’s risk of thirdhand smoke exposure. More time in a center-based daycare lowers the risks of smoke exposure since daycares are generally smoke-free.