Effect of Oral Glucose Administration on Ghrelin Levels in Normal-Height Prepubertal Children Born Small for Gestational Age (SGA)

Ghrelin is a regulator of appetite and growth hormone secretion, rising during fasting and decreasing after food intake. Children born small for gestational age (SGA) who undergo postnatal catch-up growth are at increased risk of obesity and metabolic disturbances, which may be related to impaired ghrelin regulation. This study assessed fasting and post-glucose ghrelin responses during an oral glucose tolerance test (OGTT) in prepubertal SGA children in relation to obesity and metabolic syndrome components. Ninety-eight children aged 5-9 years were included. Anthropometry, blood pressure, fasting lipids, glucose, insulin, and ghrelin were measured; BMI SDS and HOMA-IR were calculated. Ghrelin concentrations were assessed at baseline and 120 min after glucose ingestion. Ghrelin levels declined significantly during OGTT. Obese SGA children showed lower fasting and post-load ghrelin levels and a smaller decline compared with non-obese peers. Fasting and post-load ghrelin correlated inversely with BMI SDS, waist circumference, and insulin levels. In regression analyses, fasting ghrelin and its suppression were independently associated with HOMA-IR, whereas post-load ghrelin was determined by post-load insulin. These findings indicate that ghrelin dynamics in SGA children are more closely related to insulin sensitivity than adiposity and are blunted in the presence of obesity.