Serum ghrelin levels and gender-related indices of body composition in prepubertal children: a cross-sectional study.

Background: A wide variety of functions has been attributed to ghrelin, a peptide hormone secreted in the stomach. The objective of the study was to assess the association of ghrelin concentrations with body composition among Iranian children.

Methods: In this study, blood samples of 57 boys and 54 girls aged 6-10 were collected to measure ghrelin levels. Fat mass (FM) and fat-free mass (FFM) were examined by body composition analyzer. Actigraph GT3X was administered to assess children's physical activity and sleep. Data were analyzed using linear regression models.

Results: All measured parameters did not differ between genders except for sleep time which was higher and sleep efficacy which was lower in boys compared with girls. None of the FM and FFM indices studied in boys was significantly associated with ghrelin levels. In girls, however, ghrelin concentrations were significantly associated with FM (β = 0.04, P = 0.01), fat mass index (β = 0.07, P = 0.008), and fat-free mass index (β = 0.08, P = 0.04) and near-significantly associated with FFM (β = 0.03, P = 0.09) after adjusting for age, physical activity, sleep, and dietary intake.

Conclusion: Girls with higher ghrelin levels were more likely to have increased total FM and FFM. Conversely, body composition was not associated with ghrelin levels in boys. Consequently, ghrelin may influence the gender-related differences of body composition during childhood in girls. But, further study is needed to confirm our findings.