BACKGROUND: Accelerated gain in fat mass in the first months of life is considered to be a risk factor for adult diseases, given the tracking of infancy fat mass into adulthood. Our objective was to assess the influence of early growth, type of feeding and maternal variables on fat mass in early life. METHODS: In 300 healthy term infants, we longitudinally measured fat mass percentage (FM%) by air-displacement-plethysmography at 1, 3, and 6 months and abdominal visceral and subcutaneous fat measured by ultrasound at 3 and 6 months. RESULTS: Both gain in FM% and weight-for-length in the first 3 months were positively associated with FM% at 6 months of age and visceral fat at 3 months of age. Gain in FM% and weight-for-length between 3 and 6 months were both positively associated with visceral fat at 6 months. Breastfeeding duration associated positively with subcutaneous fat but not with visceral fat at 3 and 6 months. Maternal characteristics did not associate with FM% or visceral fat at 3 or 6 months. CONCLUSION: Higher gain in FM% or in weight-for-length in the first postnatal months leads not only to higher FM% but also more to accumulation of visceral fat. Exclusive breastfeeding appears to promote subcutaneous but not visceral fat in the first 6 months
