title: Limitations of studies on school-based nutrition education interventions for obesity in China: a systematic review and meta-analysis.
abstract: OBJECTIVE
  School-based nutrition education has been widely implemented in recent years to fight the increasing prevalence of childhood obesity in China.
  
  
  METHODS
  A comprehensive literature search was performed using six databases to identify studies of school-based nutrition education interventions in China. The methodological quality and the risk of bias of selected literature were evaluated. Stratified analysis was performed to identify whether different methodologies influenced the estimated effect of the intervention.
  
  
  RESULTS
  Seventeen articles were included in the analysis. Several of the included studies had inadequate intervention duration, inappropriate randomization methods, selection bias, unbalanced baseline characteristics between control and intervention groups, and absent sample size calculation. Overall, the studies showed no significant impact of nutrition education on obesity (OR=0.76; 95% CI=0.55-1.05; p=0.09). This can be compared with an OR of 0.68 for interventions aimed at preventing malnutrition and an OR of 0.49 for interventions aimed at preventing iron-deficiency anemia. When studies with unbalanced baseline characteristics between groups and selection bias in the study subjects were excluded, the impact of nutrition education on obesity was significant (OR=0.73; 95% CI=0.55-0.98; p=0.003). An analysis stratified according to the duration of intervention revealed that the intervention was effective only when it lasted for more than 2 years (OR=0.49, 95% CI=0.42-0.58; p<0.001).
  
  
  CONCLUSIONS
  Studies of school-based nutrition education programs in China have some important limitations that might affect the estimated effectiveness of the intervention.
authors.affiliation: Department of Clinical Nutrition, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.|Shanghai Key Laboratory of Children Gastroenterology and Nutrition, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Kaimeng
authors.initials: K
authors.lastname: Kong
authors.affiliation: Department of Clinical Nutrition, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.|Shanghai Key Laboratory of Children Gastroenterology and Nutrition, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Clinical Nutrition, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. Email: taoyx@163.com.|Shanghai Key Laboratory of Children Gastroenterology and Nutrition, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Yexuan
authors.initials: Y
authors.lastname: Tao
mesh_terms: D000293:Adolescent; D015982:Bias; D002648:Child; D002681:China / Q000453:epidemiology; D005247:Feeding Behavior; D005260:Female; D006266:Health Education; D006801:Humans; D008297:Male; D052756:Nutritional Sciences / Q000193:education*; D063766:Pediatric Obesity / Q000453:epidemiology / Q000517:prevention & control*; D016032:Randomized Controlled Trials as Topic; D012572:School Health Services; D012574:Schools