Issue 175 Item 13 Defects in Glucose Metabolism Persist Years After Gestational

Normoglycemic women who have had gestational diabetes (GDM) exhibit persistent metabolic abnormalities, which likely contribute to their increased risk of future type 2 diabetes and should constantly be monitored.

Dr. Mark J. McCarthy of the Oxford Centre for Diabetes, Endocrinology, and Metabolism said that "Epidemiologic studies indicate that, even when ostensibly normal glucose metabolism reappears after birth, women with previous GDM are at increased risk of type 2 diabetes later in life,"

"Metabolic studies such as ours confirm that such women still have subtle biochemical abnormalities that indicate their future diabetes risk," he added.

Dr. McCarthy and colleagues used the insulin-modified "frequently sampled intravenous glucose tolerance test" (FSIVGTT) to assess insulin action and secretion in 34 normoglycemic women with a history of GDM and 44 control women.

The two groups were matched for ethnicity, parity, and time since delivery, which was a median of 25 months in the GDM group and 28 months in the control group.

Compared with control women, women with a history of GDM more often had classic features of the metabolic syndrome, namely central obesity, dyslipidemia, and insulin resistance (higher fasting insulin and lower insulin sensitivity). They also had concomitant beta-cell dysfunction as evidenced by their lower disposition index.

The between-group differences in insulin sensitivity but not in beta-cell function were partly attributable to differences in regional and total adiposity.

"There has been a long-standing argument about whether or not the basis of type 2 diabetes lies in problems with insulin resistance or with beta-cell dysfunction," Dr. McCarthy noted. "Most people would now accept that both play a role, and this study provides support for this idea," he added.

"These data remind us that all women with previous GDM should be considered at high risk of diabetes and should be screened and treated accordingly," Dr. McCarthy said. Clin Endocrinol 2003;59:289-297.

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FACT: Cutting Calories May be Less Helpful Than Thought to Extend Lifespan
A recent story in the New York Times reducing your calories to extend your life. However, new research published in Science yesterday shows that the life-prolonging effect of reducing calories kicks in immediately, but only continues as long as one is on the diet. The protective effect of dieting snaps into place within 48 hours. New York Times September 19, 2003