Objective  To examine changing trend in obesity and its related factors and to assess the effect of intervention on obesity preliminarily among senior high school students in Haidian district of Beijing.

  Methods  We extracted data from 5 waves of National Survey on Adolescents Health Risk Behavior conducted in 2008, 2010, 2012, 2014, and 2016 among senior high school students selected in key, common and vocational high schools with multistage random cluster sampling in Haidian district of Beijing. The participants of the surveys completed anonymously a questionnaire developed by the Chinese Center for Diseases Control and Prevention.

  Results  The overall obesity prevalence rate was 10.19% among the senior high school students in the 5 waves of the survey and the rate increased from 5.36% in 2008 to 15.06% in 2016, with a significant increase (χ² = 122.01, P = 0.001) and the average annual increase of 1.60% and 0.75% for the boy and girl students during the period from 2008 to 2016. The overall obesity prevalence rate in the vocational high school students was significantly higher than that in the common high school students (χ² = 65.296, P = 0.001) and the rate in the common high school students was significantly higher than that in the key high school students (χ² = 22.078, P = 0.001). The ratios of the students reporting the consumptions of soft drinks and western fast-food increased during the survey period significantly (χ² = 634.592, P = 0.001 and χ² = 30.379, P = 0.001). Compared to those in the survey of 2008, the prevalence rate of obesity increased by 22.15%, 7.17%, 3.66% among the students of vocational, common, and key high schools in the survey of 2016. Multivariate logistic regression analyses revealed that the year of survey, gender, whether being a boarding student, type of the school, whether having internet addiction, whether living with grandparents, and self-rated academic performance were significant influencing factors of obesity among the students.

  Conclusion  The obesity prevalence rate increased continuously from 2008 to 2016 among senior high school students, especially among vocational school and boy students in Haidian district of Beijing and the increase may be correlated mainly with the increased consumption of soft drinks and western fast-food. The results suggest that school-based and family-focused interventions on personal weight control should be implemented in the students.