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.