GESTATIONAL DIABETES - SHOULD IT BE ADDED TO THE SYNDROME OF INSULIN-RESISTANCE

OBJECTIVE - The significance of gestational diabetes mellitus (GDM) re sults from its short-term detrimental effects on the fetus and its lon g-term prediction of NIDDM in the mother. We compared several variable s associated with insulin resistance between GDM and non-GDM pregnant women to show the similarities between GDM and NIDDM (and thus insulin resistance). RESEARCH DESIGN AND METHODS - On the basis of a 3-h oral glucose tolerance test (OGTT), 52 GDM patients and 127 non-GDM patien ts were recruited from pregnant, nondiabetic women who had a nonfastin g 1-h 50-g glucose screening test greater than or equal to 7.2 mmol/l (130 mg/dl) performed between 16 and 33 weeks of gestation (a total of 518 of 3,041 women drawn from six community health care prenatal clin ics were screened positive). During the OGTT, several potential marker s of insulin resistance were measured at fasting and 2-h time points, in addition to the standard glucose measurements. The relationship of these variables with the diagnosis of GDM was studied. RESULTS - GDM p atients, compared with non-GDM patients, had 1) higher prepregnancy we ight (P = 0.011), prepregnancy BMI (P = 0.006), C-peptide at fasting ( P = 0.002) and at 2 h (P < 0.001), insulin at fasting (P = 0.001) and at 2 h (P < 0.001), triglycerides at fasting (P = 0.005) and at 2 h (P = 0.003), free fatty acids at fasting (P = 0.017), beta-hydroxybutyra te at fasting (P = 0.007); and 2) lower HDL cholesterol at fasting (P = 0.029). These variables were all predictive of GDM (P < 0.036) indiv idually. Using stepwise logistic regression with all of these variable s available, fasting (P = 0.019) and 2-h (P < 0.001) insulin levels, f asting free fatty acids (P = 0.031), and fasting beta-hydroxybutyrate (P = 0.036) were statistically significant as jointly predictive of GD M. Comparisons between GDM patients and non-GDM patients matched by BM I confirmed that the metabolic abnormalities persisted when difference in BMI was taken into account. Concomitant blood pressure measurement s in women with GDM did not differ significantly from those without GD M. CONCLUSIONS - Our results show that many of the known metabolic com ponents of the syndrome of insulin resistance (syndrome X) are predict ive of GDM. These results are in keeping with the argument that GDM is one phase of the syndrome of insulin resistance. We suggest that GDM be looked upon as a component of the syndrome of insulin resistance th at provides an excellent model for the study and prevention of NIDDM i n a relatively young age-group.