Higher risk of metabolic syndrome in children and adolescents and polymorphisms in the fat mass and obesity-associated gene: a systematic review and meta-analysis

BACKGROUND: The relationship between polymorphisms in fat mass and obesity-associated gene (FTO) and the components of metabolic syndrome (MetS) has been explored among children and adolescents, but the results are inconsistent and inconclusive. METHODS: Electronic databases including Medline, Scopus, Embase, Web of Science, CNKI, and Google Scholar were searched for eligible studies, and data were extracted from each study. Standardized mean differences were calculated to examine the differences in the components of MetS between FTO genotypes. RESULTS: Forty-six studies (45,100 subjects), seven studies (4216 subjects), and six studies (2699 subjects) were included in the meta-analyses for FTOrs9939609, FTOrs1421085, and FTOrs17817449 polymorphisms, respectively. A-allele carriers of FTOrs9939609 polymorphism had higher levels of waist circumference (WC), systolic blood pressure, and fasting blood glucose, but lower levels of high-density lipoprotein cholesterol (HDL-C) than TT homozygotes (p <0.05 for all). C-allele carriers of FTOrs1421085 polymorphism had higher levels of WC and lower levels of HDL-C than TT homozygotes (p < 0.05 for both). No significant associations between FTOrs17817449 polymorphism and the components of MetS were detected. CONCLUSION: The meta-analysis demonstrates that A allele of FTOrs9939609 and C allele of FTOrs1421085 polymorphisms confer a higher risk of MetS among children and adolescents.