Insulin resistance in postmenopausal women with metabolic syndrome and the measurements of adiponectin, leptin, resistin, and ghrelin

Abstract

Metabolic syndrome (MBS) is a significant health care problem in postmenopausal women and is driven largely by obesity. We wished to assess the prevalence of insulin resistance (IR), diagnosed using practical methods, and whether several adipocyte factors (adiponectin, leptin, resistin) or the gastric peptide ghrelin, associated with cardiovascular risk, might be abnormal and may relate to IR. We evaluated 37 obese postmenopausal women with MBS and 34 matched obese premenopausal controls, as well as 14 non-obese premenopausal controls. We measured fasting glucose and insulin, performed 75 g 2 hr oral glucose tolerance and intravenous insulin tolerance tests to assess IR, and measured fasting lipids, adiponectin, leptin, resistin and ghrelin. The kinetic decline in glucose after insulin (kITT) as a marker of IR was the most frequently abnormal test (abnormal in 81%), with QUICKI, HOMA, and a modification of the Matsuda-DeFronzo index (ISIM) abnormal in 76, 73, and 68%, respectively. The GIR was abnormal in only 35% of subjects. Leptin and resistin were elevated and adiponectin and ghrelin were decreased in the postmenopausal women, compared to both groups of premenopausal controls. BMI correlated strongly with markers of insulin resistance as well as adipocytokine values. After controlling for BMI, only leptin was predictive of ISIM. Being overweight after menopause results in worsening IR and elevations in adipocytokine levels. While BMI is the most important factor, abnormal adipocytokine secretion may enhance IR and increase cardiovascular risk in postmenopausal women.