Parental fat-free mass is related to the fat-free mass of infants and maternal fat mass is related to the fat mass of infant girls.

AIM Existing studies suggest that weight and body composition of parents influence the size and body composition of their offspring, but are often inconclusive and conducted by means of inappropriate body composition methodology. Our aim was to study infant size and body composition variables in relation to body composition variables of their mothers and fathers in a well-nourished population using an accurate methodology. METHODS Between 2008 and 2011, we used air displacement plethysmography to measure the body composition of 209 parent-infant units. Parents were measured when women were in gestational week 32. Their healthy, singleton, full-term infants were measured at 1 week. RESULTS Infant fat-free mass in grams was positively related (p ≤ 0.007) to the fat-free mass in kilograms of the mothers (15.6 g/kg) and the fathers (9.1 g/kg). Furthermore, the fat mass of the daughters, but not of the sons, was positively related to the fat mass of the mothers (5.8 g/kg, p = 0.007). CONCLUSION This study found associations between the fat-free mass of parents and infants and an association between the fat mass of mothers and their infant girls. These findings may help to understand early life factors behind overweight and obesity.