Fetal growth and the physiological control of glucose tolerance in adults:a minimal model analysis

Although there is now substantial evidence linking low birthweight with imp aired glucose tolerance and type 2 diabetes in adult life, the extent to wh ich reduced fetal growth is associated with impaired insulin sensitivity, d efective insulin secretion, or a combination of both factors is not clear. We have therefore examined the relationships between birth size and both in sulin sensitivity and insulin secretion as assessed by an intravenous gluco se tolerance test with minimal model analysis in 163 men and women, aged 20 yr, born at term in Adelaide, South Australia. Birth size did not correlat e with body mass index or fat distribution in men or women. Men who were li ghter or shorter as babies were less insulin sensitive (P = 0.03 and P = 0. 01, respectively), independently of their body mass index or body fat distr ibution. They also had higher insulin secretion (P = 0.007 and P = 0.006) a nd increased glucose effectiveness (P = 0.003 and P = 0.003). Overall gluco se tolerance, however, did not correlate with birth size, suggesting that t he reduced insulin sensitivity was being compensated for by an increase in insulin secretion and insulin-independent glucose disposal. There were no r elationships between birth size and insulin sensitivity or insulin secretio n in women. These results show that small size at birth is associated with increased insulin resistance and hyperinsulinemia in young adult life but t hat these relationships are restricted to the male gender in this age group .