Independent effects of weight gain and fetal programming on metabolic complications in adults born small for gestational age

Insulin resistance (IR) and the metabolic syndrome (MS) have been reported in adults as a consequence of being born small for gestational age (SGA). The process seems to be initiated early in life; however, little is known about the progression of MS and IR in young adults. We hypothesised that being born SGA would promote a greater progression over time of IR and MS, reflecting not only the gain in weight and fat mass but also the extension of the fetal programming process. Participants were selected from a community-based cohort and born full-term either SGA (birthweight < 10th percentile) or appropriate for gestational age (25th < birthweight < 75th percentile). A total of 1,308 individuals were prospectively followed between the ages of 22 and 30 years. At both ages, individuals born SGA were more insulin-resistant and showed a significantly higher prevalence of MS. Over the 8 year follow-up, the risk of developing MS was twofold higher in those SGA, after adjustment for gain in BMI, whereas the progression of IR was not significantly affected by the birth status. Our data suggest that metabolic disorders in SGA individuals are amplified by the weight gain with time when adults, both probably resulting from fetal programming. Moreover, the modest increase in IR contrasts with the constant and much higher prevalence of MS.