title: The Influence of Secular Trends in Body Height and Weight on the Prevalence of Overweight and Obesity among Chinese Children and Adolescents.
abstract: OBJECTIVE
  To explore the influence of secular trends in body height and weight on the prevalence of overweight and obesity among Chinese children and adolescents.
  
  
  METHODS
  The data were obtained from five cross-sectional Chinese National Surveys on Students' Constitution and Health. Overweight/obesity was defined as BMI-for-age Z-score of per the Wold Health Organization (WHO) reference values. Body height and weight for each sex and age were standardized to those reported in 1985 (standardized height: SHY; standardized weight: SWY) and for each sex and year at age 7 (standardized height: SHA; standardized weight: SWA) using the Z-score method.
  
  
  RESULTS
  The prevalence of overweight/obesity in Chinese children was 20.2% among boys and 10.7% among girls in 2010 and increased continuously from 1985 to 2010. Among boys and girls of normal weight, SHY and SHA were significantly greater than SWY and SWA, respectively (P < 0.001). Among boys and girls with overweight/obesity, SHY was significantly lower than SWY (P < 0.001), and showed an obvious decreasing trend after age 12. SHA was lower than SWA among overweight boys aged 7-8 years and girls aged 7-9 years. SHY/SHW and SHA/SWA among normal-weight groups were greater than among overweight and obese groups (P < 0.001).
  
  
  CONCLUSIONS
  The continuous increase in the prevalence of overweight/obesity among Chinese children may be related to a rapid increase in body weight before age 9 and lack of secular increase in body height after age 12.
authors.affiliation: Department of Preventive Medicine, Bengbu Medical College, Bengbu 233030, Anhui, China.
authors.forename: Lian Guo
authors.initials: LG
authors.lastname: Fu
authors.affiliation: Department of Preventive Medicine, Bengbu Medical College, Bengbu 233030, Anhui, China.
authors.forename: Li Li
authors.initials: LL
authors.lastname: Sun
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston 02115, Massachusetts, USA.
authors.forename: Shao Wei
authors.initials: SW
authors.lastname: Wu
authors.affiliation: Institute of Child and Adolescent Health, School of Public Health, Peking University Health Science Center, Bejing 100191, China.
authors.forename: Yi De
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Institute of Child and Adolescent Health, School of Public Health, Peking University Health Science Center, Bejing 100191, China.
authors.forename: Xiao Hui
authors.initials: XH
authors.lastname: Li
authors.affiliation: Institute of Child and Adolescent Health, School of Public Health, Peking University Health Science Center, Bejing 100191, China.
authors.forename: Zheng He
authors.initials: ZH
authors.lastname: Wang
authors.affiliation: Department of Preventive Medicine, Bengbu Medical College, Bengbu 233030, Anhui, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Wu
authors.affiliation: Department of Preventive Medicine, Bengbu Medical College, Bengbu 233030, Anhui, China.
authors.forename: Fu Zhi
authors.initials: FZ
authors.lastname: Wang
authors.affiliation: Institute of Child and Adolescent Health, School of Public Health, Peking University Health Science Center, Bejing 100191, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
mesh_terms: D000293:Adolescent; D001827:Body Height; D001835:Body Weight; D002648:Child; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D050177:Overweight / Q000453:epidemiology* / Q000209:etiology; D063766:Pediatric Obesity / Q000453:epidemiology* / Q000209:etiology; D015995:Prevalence
keywords: Body height; Body weight; Children; Obesity; Secular trends