Context and objective: Sexagenarians born large are at lower risk for type 2 diabetes than those born small, a key feature of their body composition being a higher muscle mass, which explains their higher body mass index and also their lower fat-to-lean-mass ratio. Myogenesis is completed in early infancy under the inhibitory control of myostatin. We tested whether large-born infants from nondiabetic mothers develop an early surplus of lean mass while having a lower myostatinemia. Design, Methods, Study Participants, and Main Outcomes: In a longitudinal study (0-4 mo), we compared the body composition and endocrine markers (fasting glucose, insulin, IGF-1, high molecular weight adiponectin) of breast-fed appropriate- vs large-for-gestational-age infants (n = 125) from nondiabetic mothers. Circulating myostatin concentrations were assayed after collection of the above-mentioned data.
Setting: The study was conducted at the University Hospital for Women and Children.
Intervention: There were no interventions.
Results: Between 0-4 months, large-for-gestational-age infants switched from an adipose to a lean body composition (due to a nearly 20% excess of lean mass) and to an insulin-sensitive and hyperadiponectinemic state while having low IGF-1 concentrations and the lowest myostatinemia hitherto reported in the human (all between P ≤ .01 and P ≤ .0001).
Conclusion: Large-born infants from nondiabetic mothers were found to combine a low myostatinemia with an excess of lean mass. The fetal-neonatal control of myostatinemia deserves further attention because it could become a target of interventions that aim at reducing the risk for diabetes in later life by augmenting myogenesis in early life.