Global association of secondhand smoke exposure locations and smoking behaviour among adolescents in 99 countries

Aim
This study classified 99 countries into four income groups and then analysed the impact of secondhand smoke (SHS) exposure at home, in public places and at school, on current cigarette smoking prevalence.

Methods
We utilised data from the WHO Global Youth Tobacco Survey and a meta-analysis was conducted to evaluate the prevalence and weighted odds ratios (wORs) of adolescent smoking behaviour and SHS exposure locations.

Results
Both smoking behaviours increased with higher national income levels. Smoking behaviours in high and upper-middle-income countries (HICs and UMICs) exhibited an association with SHS exposure in public places (HIC: wOR, 3.50 [95% CI, 2.85–4.31]; UMIC: wOR, 2.90 [2.60–3.23]) compared to home. Low- and lower-middle-income countries (LICs and LMICs) showed an association with SHS exposure in the home (LIC: wOR, 5.33 [3.59–7.93]; LMIC: wOR, 2.71 [2.33–3.17]) than public places. The association between current cigarette smoking and SHS exposure at home increased with lower income levels, while anticipated future use of any form of tobacco with SHS exposure in public places rose in lower income countries.

Conclusions
Targeted interventions based on income levels are essential, emphasising home strategies in lower income countries and public place efforts in higher income countries.