Preschool children and their mothers are more exposed to paternal smoking at home than school children and their mothers.

BACKGROUND: Exposure to secondhand smoke (SHS) is a major risk to human health, and the home is the greatest single source of SHS in children. Here, the authors assessed SHS exposure of children and mothers by paternal smoking at home, and investigated how different this exposure is according to smoking location and children's age.
METHODS: Two hundred-five families were enrolled in this study as trios of fathers, mothers, and children. Nicotine concentrations in hair were measured using liquid chromatography-tandem mass spectrometry to determine long-term exposure to SHS.
RESULTS: Differences between the smoker group and nonsmoker group in nicotine levels were statistically significant in both children and their mothers. However, difference between the indoor-smoker group and outdoor-smoker group was marginally significant in children and was not significant in their mothers. In the indoor-smoker group, preschool children and their mothers had nicotine concentrations about twice as high as school children and their mothers, respectively. In the outdoor-smoker group, however, differences between two age groups in nicotine levels were significant in preschool children, but not their mothers.
CONCLUSION: These findings indicate that paternal smoking at home leads to significant exposure to SHS in their children and spouses, which is not completely prevented by smoking outside. Especially, preschool children and their mothers appear to be most at risk for SHS exposure among nonsmoking household members.