Aim: The aim of this study was to test the hypothesis that a lower birth weight, as an indicator of adverse intrauterine environment, is associated with higher serum leptin levels in European adolescents. We also examined the possible sexual dimorphism in this relationship.
Methods: Fasting serum leptin was measured in 757 European born at term adolescents (429 females) aged 14.6 ± 1.2 yr. We measured weight and height, and body mass index was calculated. Birth weight, duration of pregnancy, and duration of breast-feeding were obtained from parental records. Duration of pregnancy and breast-feeding, pubertal status, center, body mass index, and physical activity were entered as confounders in the analyses.
Results: There was a significant interaction effect between sex and birth weight on serum leptin levels (P = 0.044). We observed that body weight at birth was negatively and significantly associated with serum leptin levels only in female adolescents (β = -0.109; adjusted P = 0.008). The association persisted after further controlling for physical activity (β = -0.115; adjusted P = 0.016).
Conclusions: These findings provide further evidence for a sex-specific programming effect of birth weight on serum leptin levels. Our results also contribute to explain the detrimental health effects associated with lower birth weight, such as long-term increased risk of developing obesity and type 2 diabetes.