Central fat accretion and insulin sensitivity: differential relationships in parous and nulliparous women

BACKGROUND/OBJECTIVES: Childbearing is associated with a disproportionate accumulation of visceral fat and an increased risk of metabolic disease. However, it is unknown whether the visceral fat accretion associated with pregnancy modifies a woman’s risk for metabolic disease. The purpose of this study was to test whether the association between abdominal fat and insulin sensitivity differs by parity status in healthy overweight women. SUBJECTS/ METHODS: Intra-abdominal adipose tissue (IAAT) via CT, body composition by DXA, insulin sensitivity via intravenous glucose tolerance test and minimal model (S(I)), HOMA-IR, and cardiorespiratory fitness (VO(2max)) were assessed in 212 non-diabetic, premenopausal, overweight non-Hispanic white and African American women. RESULTS: Nulliparous women (n=98) were younger, had less IAAT and higher VO(2max), but similar S(I), HOMA-IR, and leg fat, compared to parous (n=114). In nulliparous women, IAAT was negatively associated with S(I), controlling for age, race, and body fat mass (r=−0.40, p<0.001), but this relationship was attenuated in parous women (r=−0.15, p=0.16). In multiple linear regression analysis, leg fat and IAAT were significant predictors of S(I) in nulliparous, but not parous women. CONCLUSIONS: Results suggest that greater IAAT in parous women does not lead to greater insulin resistance; rather, transient insulin resistance during pregnancy may encourage intra-abdominal fat accumulation that is metabolically benign. This underscores the need to consider parity when assessing cardiometabolic risk.