title: Prevalence of metabolic syndrome in a cohort of Chinese schoolchildren: comparison of two definitions and assessment of adipokines as components by factor analysis.
abstract: BACKGROUND
  Although attention to metabolic syndrome (MetS) in children has increased, there is still no universally accepted definition and its pathogenesis remains unclear. Our aim was to compare the current definitions of childhood MetS in a Chinese cohort and to examine the clustering pattern of MetS risk factors, particularly inclusion of leptin and adiponectin as additional components.
  
  
  METHODS
  3373 schoolchildren aged 6 to 18 years were recruited. Anthropometric and biochemical parameters and adipokines were measured. MetS was identified using both the International Diabetes Federation (IDF) and a modified Adult Treatment Panel III (ATP III) definitions. Exploratory factor analysis was performed to establish grouping of metabolic characteristics.
  
  
  RESULTS
  For children ≥ 10 years, the prevalence of MetS was 14.3% in the obese group and 3.7% in the overweight group according to the new IDF definition, and 32.3% in the obese group and 8.4% in the overweight group according to the modified ATPIII definition. Frequency of hypertriglyceridemia, low high-density lipoprotein cholesterol (HDL-C), impaired fasting glucose, elevated blood pressure, and central obesity according to the new IDF definition was 16.7%, 20.7%, 15.8%, 25.5% and 75.5% in obese boys and 14.7%, 24.0%, 12.0%, 11.0% and 89.0% in obese girls, respectively. Metabolic abnormalities in children under 10 years of age were also noted. Using factor analysis on eight conventional variables led to the extraction of 3 factors. Waist circumference (WC) provided a connection between two factors in boys and all three factors in girls, suggesting its central role in the clustering of metabolic risk factors. Addition of leptin and adiponectin also led to the extraction of 3 factors, with leptin providing a connection between two factors in girls. When using WC, mean arterial pressure, triglyceride/HDL-C ratio, HOMA-IR and leptin/adiponectin ratio as variables, a single-factor model was extracted. WC had the biggest factor loading, followed by leptin/adiponectin ratio.
  
  
  CONCLUSIONS
  MetS was highly prevalent amongst obese children and adolescents in this cohort, regardless of the definition used. Central obesity is the key player in the clustering of metabolic risk factors in children, supporting the new IDF definition. Moreover, our findings suggest that a common factor may underlie MetS. Leptin/adiponectin ratio as a possible component of MetS deserves further consideration.
authors.affiliation: Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (CAMS & PUMC), Beijing 100730, China.
authors.forename: Qiaoxuan
authors.initials: Q
authors.lastname: Wang
authors.forename: Jinhua
authors.initials: J
authors.lastname: Yin
authors.forename: Lu
authors.initials: L
authors.lastname: Xu
authors.forename: Hong
authors.initials: H
authors.lastname: Cheng
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Zhao
authors.forename: Hongding
authors.initials: H
authors.lastname: Xiang
authors.forename: Hugh Simon
authors.initials: HS
authors.lastname: Lam
authors.forename: Jie
authors.initials: J
authors.lastname: Mi
authors.forename: Ming
authors.initials: M
authors.lastname: Li
mesh_terms: D054392:Adipokines / Q000032:analysis*; D000293:Adolescent; D002648:Child; D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D015331:Cohort Studies; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology*; D009765:Obesity / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors; D009626:Terminology as Topic
chemical_list: D054392:Adipokines