JMIR Publications

ABSTRACT

Background:

It is well known that secondhand smoke exposure in childhood or adolescence is positively associated with morbidity and mortality. However, less is known about the current status and most recent trends in secondhand smoke exposure in adolescents in China.

Objective:

We aimed to assess the recent changes in the prevalence of secondhand smoke exposure among adolescents in China using nationally representative data.

Methods:

We used data from two repeated national cross-sectional surveys conducted in 2013-14 and 2019. A total of 155,117 students (median age: 13.5 years) in 2013-14 and 147,270 students (median age: 13.1 years) in 2019 were included in this study. Sociodemographic factors and secondhand smoke exposure information were collected via a standardized questionnaire. Exposure was defined as secondhand smoke exposure ≥1 day during the past 7 days at home or in public places. The other frequencies of secondhand smoke exposure (i.e. ≥3 days, ≥5 days, and every day) during the past 7 days were also assessed. Weighted prevalence of secondhand smoke exposure was calculated according to the complex sample design for surveys.

Results:

The prevalence of secondhand smoke exposure in any place (home or public places on ≥1 day during the past 7 days) decreased from 2013-14 (72.9% 95% CI: 71.5-74.3) to 2019 (63.2%, 62.0-64.5), as did exposure at home (2013-14: 44.4% [43.1-45.7]; 2019: 34.1% [33.1-35.2]) and in public places (2013-14: 68.3% [66.9-69.6]; 2019: 57.3% [56.0-58.6]). The prevalence of secondhand smoke exposure decreased with the increase of Gross Domestic Product per capita in each of two survey years irrespective of exposure frequency, and location. The prevalence of exposure by other frequency (i.e. ≥3 days, ≥5 days, and every day during the past 7 days) also decreased in any place, at home, and in public places. Secondhand smoke exposure was associated with higher school grade level (9th vs. 7th grade: OR=1.76, 95%CI=1.68-1.84), boys (vs. girls: OR=1.18, 95%CI=1.15-1.22), urban (vs. rural: OR=1.10, 95%CI=1.01-1.19) and cigarette smoking (vs. no: OR=6.67, 95%CI=5.83-7.62).

Conclusions:

Although the prevalence of secondhand smoke exposure among Chinese adolescents declined from 2013-14 to 2019, it remains unacceptably high. More effective strategies and stronger action are needed in China to further, and dramatically, curb secondhand smoke exposure to adolescents.