Objective: To analyze prevalence and associated factors of attempting e cigarettes use among senior high school students in Beijing City between 2019 and 2023, in order to providing references for the construction of smoke free senior high schools environments. Methods: In 2019, 9 137 students from 44 senior high schools in Beijing City were monitored, including 27 general senior high schools and 17 vocational senior high schools. In 2023, the study included 6 709 students from 30 senior high schools comprising 21 general senior high schools and 9 vocational senior high schools. On site investigations using anonymous questionnaires were conducted. The monitoring content included demographic information, second hand smoke exposure, tobacco product use and tobacco awareness. Chi square test was used to compare the differences of various indicators in different groups, and multivariate Logistic regression analysis was adopted to analysis the influencing factors among senior high school students attempting to use e cigarettes between 2019 and 2023. Results: In 2019, the rates of vocational senior high school and general senior high school students attempting to use e-cigarettes were 22.57% and 9.78%, respectively. In 2023, it decreased to 14.39% and 6.43%, respectively. In 2019 ( OR =1.59,95% CI =1.35-1.88) and 2023 ( OR =1.71,95% CI =1.38-2.11), vocational senior high school students both hold higher risk of attempting to use e-cigarettes,compared with general senior high school students. In 2019, non-indigenous senior high school students attempting to use e cigarettes were more than indigenous senior high school students ( OR = 1.28 , 95% CI =1.05-1.56). In 2019 ( OR =1.62, 95% CI =1.34-1.95) and 2023 ( OR =1.77, 95% CI =1.35-2.31), smoking anywhere in households increased the risk of attempting to use e-cigarettes among senior high school students. In both 2019 and 2023, not attempting to smoke cigarettes ( OR =0.24,95% CI =0.21-0.29; OR =0.15,95% CI =0.11-0.19), not currently smoking cigarettes ( OR =0.29,95% CI =0.22-0.40; OR =0.30,95% CI =0.17-0.53), not being exposed to secondhand smoke in school ( OR =0.62, 95% CI = 0.53 -0.72; OR =0.51, 95% CI =0.41-0.64) or in outdoor public places ( OR =0.74, 95% CI =0.63-0.86; OR = 0.62 , 95% CI =0.50-0.78) all reduced the risk of attempting to use e-cigarettes among senior hgih school students( P <0.05). Conclusion The influencing factors of attempts by senior high school students in Beijing City to use e-cigarettes are generally consistent between 2023 and 2019, with a focus on vocational senior high schools to ensure the continuity of intervention measures and promote the construction of smoke free senior high schools.

Objective: To understand the prevalence and related factors of tobacco use among junior high school students in Beijing, so as to provide evidence to effectively conduct tobacco control intervention strategy. Methods: From April to June in 2019 and 2023, 6 489 and 6 898 junior high school students were selected by the probability proportion to size(PPS) method, and a total of 13 387 questionnaires were completed. Questionnaire on tobacco monitoring among junior high school students in Beijing was completed by selffilling. The monitoring content included demographic information, secondhand smoke exposure, tobacco product use, tobacco awareness, etc. Chisquare test was used to compare the difference of various indicators in different groups, and multivariate Logistic regression analysis was adopted to analysis the influencing factors related to the current smoking among junior high school students. Results: In 2019,the current traditional cigarettes and ecigarette smoking rates among junior high school students in Beijing were 1.34%, 1.88%, respectively, and decreased to 0.81%, 1.06% in 2023 (χ2=8.36, 15.17, P＜0.01). The attempted traditional cigarettes and ecigarette smoking rates among junior high school students in Beijing decreased from 6.67%, 6.47% in 2019 to 3.93%, 4.16% in 2023 (χ2=49.99, 35.26, P＜0.01). In 2019, the secondhand smoke exposure rates of junior high school students at homes, indoor public places, and outdoor public places were 31.04%, 44.94%, and 49.88% respectively which decreased to 22.59%, 30.23%, and 36.14% in 2023 (χ2=121.63, 308.60, 257.41, P<0.01). In 2023, male students (OR=2.88), senior students (grade 2 and 3) (OR=4.37, 4.92), disposable pocket money>20 yuan/week (OR=2.01), secondhand smoke exposure at home (OR=2.74), indoor public places (OR=2.64), perception that smoking makes young people more attractive (OR=6.29), and perception that ecigarettes help quit smoking (OR=4.31) were associated with higher tobacco use (P<0.05). Conclusions Tobacco use and secondhand smoke among junior high school students in Beijing decrease significantly. Tobacco control interventions should be provided for junior high school students continuously with a focus on ecigarettes use to promote physical and mental health development among students.