Exposure to secondhand smoke among school-going adolescents in Malaysia: Results from the National Health and Morbidity Survey (NHMS) 2022: Adolescent Health Survey (AHS).

Introduction: The adverse effects of secondhand smoke (SHS) exposure on health have been well established. Using the NHMS 2002: Adolescent Health Survey (AHS), this study attempts to evaluate the extent and factors associated with SHS exposure among Malaysian school-going adolescents.

Methods: We conducted the NHMS 2022: AHS to gather a representative sample of school-age teenagers. We employed a cross-sectional study design and a multi-stage sampling procedure. We utilized a pre-validated self-administered questionnaire to collect data from the selected respondents. The data analysis included adjusted odds ratios (AORs) with 95% confidence intervals (95% CIs). Additionally, we investigated the possible two-way interactions between the independent variables.

Results: The SHS prevalence was 42.0%. Exposure to secondhand smoke (SHS) was associated with male gender (AOR=1.28; 95 CI: 1.20-1.38), older age (AOR=1.46; 95% CI: 1.33-1.60), Malay (AOR=1.88; 95% CI: 1.49-2.37), Bumiputra Sabah (AOR=2.23; 95% CI: 1.67-2.99), Bumiputra Sarawak (AOR=2.43; 95% CI: 1.80-3.28), and Chinese ethnicity (AOR=2.89; 95 CI: % 2.30-3.64), as well as current smoking (AOR=2.78; 95% CI: 2.50-3.09), having separated or divorced parents (AOR=1.12; 95% CI: 1.02-1.23), and parental tobacco product use (AOR=4.75; 95% CI: 4.44-5.08). We found significant interactions between: 1) Age group with gender and ethnicity; 2) Gender and ethnicity; and 3) Parental smoking status with gender, response to tobacco use, parents' marital status, and ethnicity.

Conclusions: Parental characteristics, sociodemographic characteristics, and SHS exposure are strongly correlated. In addition, there is evidence of smoking displacement to the house from other areas by parents/guardians. This study offers a fresh perspective on how these variables influence the likelihood of SHS exposure for Malaysian school-age teenagers. More efforts should focus on parental variables and sociodemographic traits, especially parental smoking cessation support.