Duration of breastfeeding and gender are associated with methylation of the LEPTIN gene in very young children

BACKGROUND: Perinatal environmental factors have been associated with the metabolic programming of children and consequent disease risks in later life. Epigenetic modifications that lead to altered gene expression may be involved. Here, we study early life environmental and constitutional factors in association with the DNA methylation of leptin (LEP), a non-imprinted gene implicated in appetite regulation and fat metabolism. METHODS: We investigated maternal education, breastfeeding, and constitutional factors of the child at 17 mo of age. We measured the DNA methylation of LEP in whole blood and the concentration of leptin in serum. RESULTS: Duration of breastfeeding was negatively associated with LEP methylation. Low education (<= 12 y of education) was associated with higher LEP methylation. Boys had higher birth weight and lower LEP methylation than girls. An inverse association was established between birth weight per SD increase (+584g) and LEP methylation. High BMI and leptin concentration were associated with lower methylation of LEP. CONCLUSION: The early life environment and constitutional factors of the child are associated with epigenetic variations in LEP. Future studies must reveal whether breastfeeding and the associated decrease in LEP methylation is an epigenetic mechanism contributing to the protective effect of breastfeeding against obesity.