In utero and early childhood exposure to secondhand smoke in Taiwan: a population-based birth cohort study

OBJECTIVES This study provides secondhand smoke (SHS) exposure data in utero and after birth when children were at 18 months, 36 months and 66 months old, and it identifies risk factors for the early childhood SHS among 18-month-old infants living in smoker and non-smoker households. STUDY DESIGN The data come from the Taiwan Birth Cohort Study, a longitudinal survey of a birth cohort born in 2005. This study used the survey wave when children were 18 months old (n=18 845) for statistical analysis of early childhood SHS exposure. Logistic regression was used to identify the risk factors of the SHS exposure. RESULTS Approximately 62% of the 18-month-old infants lived in a household with at least one smoker, with the father being the smoker in 84% of those households. Among these infants living in a smoker household, 70% were exposed to SHS and 36% were exposed to heavy SHS in utero, and the prevalence was approximately 66% and 17% after birth for SHS and heavy SHS, respectively. The number and the existence of smokers in the household, parents' smoking status, father's educational attainment and being a first-born baby are strong predictors of early childhood heavy SHS exposure. CONCLUSIONS Encouraging families to have a smoke-free home environment, empowering women to ensure their perspectives and rights are embedded into tobacco control efforts and educating families about the health risks from childhood SHS exposure, especially among people living in households with smokers, will protect non-smoking adults and children from SHS exposure.