Early metabolic defects following gestational diabetes in three ethnic groups of anti-GAD antibodies negative women with normal fasting glucose.

OBJECTIVE: To characterise early metabolic abnormalities and the impact of ethnicity following gestational diabetes mellitus (GDM). DESIGN: Women with a history of GDM belonging to three different ethnic groups were evaluated. Using the insulin-modified, frequently-sampled intravenous glucose tolerance test (FSIVGTT) and HOMA we studied 34 European, 16 South Asian and 10 Afro-Caribbean women with normal fasting glucose following GDM and 44 European, 16 South Asian and 19 Afro-Caribbean controls to assess insulin action and secretion. RESULTS: European post-GDM women had lower insulin sensitivity by FSIVGTT [0.6 (0.1-5.1) vs 1.5 (0.8-2.8) x10(-4).min(-1).pmol(-1).l(-1), p=0.010, adjusted for BMI p=0.054] and by HOMA [72(22-235) vs 153(55-421)%, p=0.004, adjusted for BMI p=0.006], and reduced -cell function [lower disposition index 0.05(0.01-0.40) vs 0.11(0.05-0.25)min(-1), p=0.017] compared with controls. South Asian post-GDM women had decreased -cell function [lower HOMA (%B) (73 (37-147) vs 124 (59-262) %, p=0.048 and acute insulin response to glucose (463 (131-1639) vs 1039 (393-2748) pmol/l h, p=0.052] than controls. Afro-Caribbean post-GDM women had lower glucose disappearance rate [1.3(0.6-2.8) vs 2.6 (1.8-3.8) 10(-2)/min, p=0.003] than controls, suggesting subtle glucose intolerance. CONCLUSIONS: Women with a history of GDM of three different ethnic groups, even in the presence of normal fasting glucose, display a range of metabolic abnormalities, including -cell dysfunction with variable insulin resistance. These derangements may be influenced by ethnicity.