Background: We assessed relationships between ectopic lipid stores [intrahepatic (IHL), intramyocellular (IMCL), and extramyocellular (EMCL)] and parameters of insulin sensitivity in women with gestational diabetes (GDM) compared with BMI-matched controls.
Methods: We performed a case-control analysis nested within a prospective cohort study of 54 pregnant women with normal weight, overweight, and obesity without pregestational diabetes. From the prospective cohort, 7 women developed GDM. Three additional women with GDM were recruited in late pregnancy to increase sample size. All women underwent insulin clamps to assess insulin disposal (Rd) and endogenous glucose production (EGP); 1H magnetic resonance spectroscopy to assess IHL, IMCL, and EMCL content; MRI to assess subcutaneous abdominal (SAT) and visceral adipose tissue (VAT) volume, BODPOD to assess % body fat, fat mass, and fat free mass; and measurement of fasting free fatty acid levels. Measures were performed in early and late pregnancy [mean (minute-max), 15.5 (12.4-17.6) and 34.1 (31.6-37.3) weeks gestation, respectively].
Results: Women with GDM were matched on BMI to women in the prospective cohort who did not develop GDM. In early pregnancy, compared to controls, women with GDM had greater % body fat (P=.02), fasting free fatty acids (P<.01), and insulin resistance (lower Rd, P<.01), but did not significantly differ in amounts of VAT, SAT, IHL, EGP, IMCL, or EMCL. In late pregnancy, cases and controls did not significantly differ by body composition or free fatty acid levels, but insulin resistance remained greater among women with GDM (P=.02).
Conclusion: Women who would be later diagnosed with GDM exhibited greater percent body fat, insulin resistance, and fasting free fatty acid levels early in pregnancy, but not visceral or ectopic fat stores. Accumulation of excess lipids in VAT and ectopic fat stores does not appear to play an important role in distinguishing women who develop GDM from those that do not.
K. Vesco: None. M.C. Leo: None. M. Francisco: None. N.E. Marshall: None. W. Rooney: None. E. Baetscher: None. A.M. Valent: None. J.Q. Purnell: Advisory Panel; Self; Novo Nordisk A/S.
National Institute of Diabetes and Digestive and Kidney Diseases (R01DK098707)