Sexual dimorphism of leptin and adiposity in children between 0 to 10 years: A Systematic Review and meta-analysis

Abstract

Abstract Background It has been described in adolescents and adults differences by sex in blood levels of leptin and adiposity, however, it is not yet clear if these differences arise from the prepubertal stage in subjects with a normal-weight. Therefore, we examine whether there are differences by sex in levels of blood leptin and body fat per cent (BFP) in children with a normal-weight between 0 to 10 years old. Methods Search strategy: Eligible studies were obtained from three electronic databases (Medline, Web of Science, and Embase) and contact with experts. Selection criteria: Healthy children under 10 years of age with normal-weight according to age.Data collection and analyses: Data were extracted by four independent reviewers using a predesigned data collection form. The statistical analysis was performed in the R program. Results Of initially identified 12363 publications, twenty-one studies were included (5516 girls and 5629 boys) in the systematic review and meta-analysis. The sex was associated with the overall effect on blood leptin (Pooled MD= 1.69 ng/mL, 95%CI: 1.21 to 2.17) and BFP (Pooled MD= 3.44%, 95%CI: 2.55 to 4.33), being both higher in girls. This finding was consistently in the majority of age groups studied (Newborns, 0,25 to 0.5 yrs, 3 to 5.9 yrs, 6 to 7.9 yrs, 8 to 10 yrs). Conclusion: The results of our meta-analyses support the sexual dimorphism in circulating blood leptin and BFP between girls and boys with normal-weight from birth to ten years of age.