title: Association between obesity and sexual maturation in Chinese children: a muticenter study.
abstract: OBJECTIVE
  We aimed to evaluate the current status of sexual maturation of Chinese children, to examine the association between obesity and early sexual maturation in boys and compare it with girls and to test the hypothesis that the associations differ by gender.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  A representative sample involving 9812 boys and 8895 girls aged 6-18 years who participated in the Chinese Children and Adolescent Metabolic Syndrome Epidemiologic Study (July 2009- July 2010) were surveyed.
  
  
  METHODS
  All subjects had complete anthropometry and sexual maturation data. SUBJECTS who reached Tanner stage 2 or more (5601 boys and 6538 girls) were divided into tertiles based on the timing of sexual maturation. The subjects in the earliest tertile were included into the early-maturing group, and the middle tertile and the latest tertile into the not early-maturing group. Overweight was defined as a body mass index (BMI) ⩾85th percentile and obesity ⩾95th percentile. Logistic regression analysis was used to test how early maturation affected the risk of overweight. Multiple linear regression was used to examine the association between fatness (BMI Z-score) and sexual maturation.
  
  
  RESULTS
  Slightly more boys were obese than girls (P<0.01). The median age for girls of the Tanner stage 2 was 9.69 years, and for boys of Tanner stage 2 was 11.25 years. BMI Z-score were higher (P<0.01) in both early-maturing girls and boys, compared with the non-early maturers, respectively. Early sexual maturation was positively associated with obesity in both girls and boys. With covariates adjusted and using non-early maturing as the reference group, odds ratios for combined overweight were 1.48 for boys and 2.64 for girls, and for obesities were 1.61 for boys and 3.49 for girls, respectively.
  
  
  CONCLUSIONS
  Obesity is positively associated with sexual maturation in both boys and girls, and the association does not differ by gender, but the association is stronger in girls than in boys.
authors.affiliation: Department of Endocrinology of Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China.
authors.forename: Y L
authors.initials: YL
authors.lastname: Dai
authors.affiliation: Department of Endocrinology of Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China.
authors.forename: J F
authors.initials: JF
authors.lastname: Fu
authors.affiliation: First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
authors.forename: L
authors.initials: L
authors.lastname: Liang
authors.affiliation: Beijing Children's Hospital of Capital Medical University, Beijing, China.
authors.forename: C X
authors.initials: CX
authors.lastname: Gong
authors.affiliation: Children's Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: F
authors.initials: F
authors.lastname: Xiong
authors.affiliation: Children's Hospital of Shanghai Fudan University, Shanghai, China.
authors.forename: F H
authors.initials: FH
authors.lastname: Luo
authors.affiliation: General Hospital of Tianjin Medical University, Tianjin, China.
authors.forename: G L
authors.initials: GL
authors.lastname: Liu
authors.affiliation: Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanjing, China.
authors.forename: S K
authors.initials: SK
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000367:Age Factors; D044466:Asian People; D015992:Body Mass Index; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009749:Nutrition Surveys; D063766:Pediatric Obesity / Q000150:complications / Q000453:epidemiology* / Q000503:physiopathology; D015995:Prevalence; D011627:Puberty / Q000502:physiology; D011634:Public Health; D012307:Risk Factors; D012574:Schools; D012737:Sex Factors; D012741:Sexual Maturation / Q000502:physiology