Relationships between cord blood leptin and ghrelin levels, milk intake and weight gain in human infants

Abstract

Leptin and ghrelin are hormones involved in the regulation of appetite and adiposity. Leptin suppresses appetite and induces weight loss; ghrelin stimulates appetite and promotes weight gain. The study reported in this thesis was designed to examine the relationship of cord blood leptin and ghrelin with milk intake over the first week of life, and with infant growth up to twelve weeks of age. One hundred term formula fed newborns were recruited at birth. Leptin and ghrelin were measured in cord blood by radioimmunoassay. Milk intake was measured by weighing of bottles of formula milk before and after feeding. Measurements of weight, length and head circumference were taken at birth, seven days and at twelve weeks of age. A number of control variables were also measured. Birthweight was a significant predictor of mean milk intake, which rose significantly from days 1 to 7, with no difference between males and females. Weight gain or loss in the early neonatal period was a direct and significant consequence of milk intake consumed over that period. There was no relationship between cord blood leptin or ghrelin (controlling for birthweight) on the infants' milk intake over the first 24 hours of life or on their mean milk intake over the first week of life. Weight gain was significantly correlated with birthweight, with higher birthweight associated with lower weight gain. There was no relationship between cord leptin and weight gain to three months of age after adjusting for birthweight; but lower cord ghrelin levels were significantly associated with slower weight gain.