Ethnic differences in insulin resistance and its consequences in older Mexican American and non-Hispanic white women

Abstract

Background. This study was initiated to test the hypothesis that older, healthy, nondiabetic Mexican American women would be relatively resistant to insulin-mediated glucose disposal, hyperinsulinemic, and dyslipidemic as compared to a matched group of non-Hispanic White (NHW) women. Methods. The study, cross-sectional in nature, involved 14 Mexican American and 19 NHW healthy, normotensive, nondiabetic, postmenopausal women of similar age and body mass index. It took place in the General Clinical Research Center at Stanford Medical Center. Measurements were made of fasting plasma glucose, insulin and lipid concentrations, and plasma glucose and insulin concentrations following a 75 gram oral glucose challenge. Resistance to insulin-mediated glucose disposal was estimated by the steady-state plasma glucose (SSPG) concentration achieved at the end of a 3-hour constant infusion of glucose, insulin, and somatostatin. Results. Mexican American women had significantly greater glucose (p < = .04). Conclusion. Older Mexican American women are more insulin resistant, glucose intolerant, and hyperinsulinemic, and have a lower HDL-cholesterol than a matched group of non-hispanic White peers. These results were observed despite the exclusion of individuals with non-insulin dependent diabetes mellitus (NIDDM).