Early second-hand smoke exposure and child and adolescent mental health: evidence from Hong Kong's "Children of 1997' birth cohort

Background and AimsSecond-hand smoke (SHS) exposure is associated negatively with childhood behavioural problems in western settings. In a developed non-western setting, we estimated the associations of early SHS exposure during the prenatal and postnatal periods with several aspects of adolescent mental health. DesignMultivariable linear regression was used to estimate the adjusted associations of pre- and postnatal SHS exposure with adolescent mental health. SettingHong Kong. ParticipantsPopulation-representative Children of 1997 birth cohort. Behavioural problems at similar to 11years were available for 5598, self-esteem at similar to 11years for 6937 and depressive symptoms at similar to 13years for 5797. MeasurementsSHS was categorized as no SHS exposure, occasional prenatal SHS exposure from non-parental sources, daily prenatal SHS exposure from non-parental sources, postnatal SHS exposure from non-parental sources, prenatal and postnatal SHS exposure from non-parental sources, occasional paternal smoking, daily paternal smoking and any maternal smoking. Behavioural problems were assessed from parent-reported Rutter score, self-esteem from self-reported Culture-Free Self-Esteem Inventory score and depressive symptoms from self-reported Patient Health Questionnaire-9 score. FindingsPrenatal SHS exposure from non-parental sources was associated with behavioural problems at similar to 11years (1.24, 95% confidence interval 0.20-2.28) adjusted for sex, age of assessment, survey mode (for depressive symptoms only), socio-economic position (SEP), mother's birthplace, gestational age and parity; paternal smoking and maternal smoking were associated with more mental health problems but also with lower SEP. ConclusionsIn Hong Kong, prenatal second-hand tobacco smoke exposure appears to be a risk factor for behavioural problems at age 11years independent of socio-economic position.