Influence of Maternal Obesity on Insulin Sensitivity and Secretion in Offspring

OBJECTIVE The purpose of this study was to clarify the effects of maternal obesity on insulin sensitivity and secretion in offspring. RESEARCH DESIGN AND METHODS Fifty-one offspring of both sexes of obese (Ob group) and 15 offspring of normal-weight (control group) mothers were studied. Plasma glucose, insulin, and C-peptide were measured during an oral glucose tolerance test (OGTT). Insulin sensitivity was calculated using the oral glucose insulin sensitivity index, and insulin secretion and beta-cell glucose sensitivity were computed by a mathematical model. Fasting leptin and adiponectin were also measured. Body composition was assessed by dual-X-ray absorptiometry. RESULTS No birth weight statistical difference was observed in the two groups. Of the Ob group, 69% were obese and 19% were overweight. The Ob group were more insulin resistant than the control group (398.58 +/- 79.32 vs. 513.81 +/- 70.70 ml(-1) x min(-1) x m(-2) in women, P < 0.0001; 416.42 +/- 76.17 vs. 484.242 +/- 45.76 ml(-1) x min(-1) x m(-2) in men, P < 0.05). Insulin secretion after OGTT was higher in Ob group than in control group men (63.94 +/- 21.20 vs. 35.71 +/- 10.02 nmol x m(-2), P < 0.01) but did not differ significantly in women. beta-Cell glucose sensitivity was not statistically different between groups. A multivariate analysis of variance showed that maternal obesity and offspring sex concurred together with BMI and beta-cell glucose sensitivity to determine the differences in insulin sensitivity and secretion observed in offspring. CONCLUSIONS Obese mothers can give birth to normal birth weight babies who later develop obesity and insulin resistance. The maternal genetic/epigenetic transmission shows a clear sexual dimorphism, with male offspring having a higher value of insulin sensitivity (although not statistically significant) associated with significantly higher insulin secretion than female offspring.