title: Empirical change in the prevalence of overweight and obesity in adolescents from 2007 to 2011 in Guangzhou, China.
abstract: There is a strong evidence of an increasing secular trend in obesity in adolescents in most of the world over the past 10 years. However, no studies have been reported on this trend in Guangzhou, one of the most urbanized areas in China. This study assessed the empirical changes in body mass index (BMI) and the prevalence of overweight and obesity of adolescents in Guangzhou from 2007 to 2011. The data were derived from the surveys on students' constitution and health carried out by government in 2007, 2009, and 2011 in Guangzhou. Randomly, 17,157 students in 2007, 26,381 students in 2009, and 36,328 students in 2011, aged 12 to 18, from schools in the four urban districts were examined. Anthropometric parameters were measured in all students. Adiposity status was estimated using BMI according to the Working Group on Obesity in China criteria. The total prevalence of overweight and obesity increased from 8.1 % and 3.1 % in 2007 to 10.0 % and 4.2 % in 2011, respectively (P < 0.05). However, the total prevalence of obesity decreased significantly from 4.5 % in 2009 to 4.2 % in 2011 (P < 0.05). The prevalence of overweight and obesity in males was significantly higher than that in females in each year among the 4 years (P < 0.05).
  
  
  CONCLUSIONS
  Although the prevalence of adolescent overweight and obesity in Guangzhou in 2011 is still lower than the average values of Chinese large coastal cities, a significant increase was still found in their prevalence from 2007 to 2011. However, the adolescent obesity, but not the overweight prevalence, starts to decrease from 2009 to 2011.
authors.affiliation: Department of Maternity and Child Health Care, School of Public Health, Sun Yat-Sen University, Guangzhou, 510080, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Ma
authors.forename: Jincheng
authors.initials: J
authors.lastname: Mai
authors.forename: Jin
authors.initials: J
authors.lastname: Jing
authors.forename: Zhaomin
authors.initials: Z
authors.lastname: Liu
authors.forename: Yanna
authors.initials: Y
authors.lastname: Zhu
authors.forename: Yu
authors.initials: Y
authors.lastname: Jin
authors.forename: Yajun
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000453:epidemiology*; D050177:Overweight / Q000453:epidemiology*; D015995:Prevalence; D013334:Students; D014505:Urban Population