Survey of Secondhand Smoke for 3-Year-Old Children in the Current Era of New Tobacco Products.

Aim: To investigate children's exposure to secondhand smoke and aerosols in the current era of new tobacco products.

Methods: A total of 200 children were recruited from among children who had undergone health checkups for 3-year-olds at the clinic. We investigated the smoking status of their families using a questionnaire and measured urinary cotinine concentrations in their children. The children were divided into four groups based on their families' smoking status: no smokers (n = 114), exclusive combustion cigarette smokers (n = 35), both combustion cigarette and heated tobacco product smokers (n = 12) and exclusive heated tobacco product smokers (n = 39).

Results: Of the 200 children, 53 (26.5%) had detectable urinary cotinine levels. Of these, 12 (6.0%) were classified as having heavy exposure to secondhand smoke (urinary cotinine concentration ≥ 5 ng/mL). Urinary cotinine concentrations among children living with exclusive heated tobacco product smokers were significantly lower than those among children living with exclusive combustion cigarette smokers, but higher than those in children whose family members did not smoke at all. Relative to exclusive combustion cigarette smokers, exclusive heated tobacco product smokers were significantly more likely to smoke indoors.

Conclusions: Secondhand aerosol exposure from heated tobacco products may be reduced but cannot be completely eliminated.