Abnormal glucose tolerance is associated with diminished postload change in leptin levels in women.

Background: It is generally accepted that the metabolic effects of leptin are diminished in the obese due to leptin resistance. Hormone resistance may develop if diurnal (including meal-related) changes in hormone levels are disrupted. We sought to describe leptin changes after a 75 g oral glucose tolerance test (OGTT) in women with a prior diagnosis of gestational diabetes mellitus (a high risk group for the metabolic syndrome) compared to that in healthy controls.

Methods: In 2000 a retrospective cohort study was performed on women who had been diagnosed with gestational diabetes mellitus (WHO criteria 1985, n = 57) between 1996 and 1998 and on a healthy control female group (n = 36) all of whom had had a prior pregnancy without any diagnosis of diabetes. All the women underwent a standard 75 g OGTT. Serum leptin was measured by radioimmunoassay before and 90 min after the OGTT.

Results: Using multilevel models of change, fasting leptin levels were shown to be associated with body mass index; 10.1% (95% CI 8.1-12.1%) increase per 1 kg/m(2) increase in body mass index), homeostasis model assessment insulin sensitivity; 0.4% (95% CI 0.2-0.7%) decrease per 1% increase in insulin sensitivity); abnormal glucose tolerance (24% decrease, 95% CI 8-37%); and smoking (31% decrease, 95% CI 16-44%). Postload (90 min) leptin levels decreased significantly in women with normal glucose tolerance by 13% (95% CI 8-18%), while no significant change in postload leptin level was apparent in women with abnormal glucose tolerance (3% increase, 95% CI -4% to 29%).

Conclusions: Disturbed leptin changes were found following an OGTT in women with abnormal glucose tolerance that might be either a cause or a consequence of leptin resistance.