Maternal BMI and serum leptin concentration of infants in the first year of life

Aim: To evaluate the relationship between serum leptin concentration in infants and infant and maternal BMI. Methods: 75 healthy term infants aged 0-12 mo, 51 exclusively breastfed (BF) for at least 4 mo and 24 formula fed (FF), were included in a cross-sectional study. Weight, length and cranial circumference of infants and their mothers were measured, body mass index (BMI) was calculated using the formula weight (kg)/height (m(2)) and infant serum leptin concentration was determined. Results: A significant positive correlation between infant serum leptin concentration and maternal BMI was observed in BF infants (r = 0.389, p = 0.005), confirmed in a multiple regression model adjusted for infant age and infant BMI (beta = 0.065, p = 0.006), but not in FF infants. As regards the first 4 mo of life, we have already observed a positive correlation between infant serum leptin concentration and maternal BMI in BF infants (beta = 0.113, p = 0.005), but not in FF infants. Conclusion: In BF infants, serum leptin concentration correlates positively with maternal BMI. Higher maternal BMI values might increase leptin levels in breast milk, and maternal adiposity could be involved in infant energy balance.