IS HYPERINSULINEMIA A CENTRAL CHARACTERISTIC OF A CHRONIC CARDIOVASCULAR RISK FACTOR CLUSTERING SYNDROME - MIXED FINDINGS IN ASIAN INDIAN, CREOLE AND CHINESE MAURITIANS

The aim of the study was to investigate whether the constellation of c ardiovascular disease risk factors, described as Insulin Resistance Sy ndrome, exists in the multi-ethnic population of Mauritius, and to ass ess whether hyperinsulinaemia is the key feature of this syndrome. A s ample of 5080 Mauritian subjects (aged 25-74 years) was examined in a noncommunicable diseases survey in 1987. Survey procedure included an oral glucose tolerance test, and anthropometric, blood pressure, plasm a lipids and serum insulin measurements. Abnormal glucose tolerance (d iabetes and impaired glucose tolerance), general obesity, upper-body o besity, hypertension, low HDL-cholesterol, and hypertriglyceridaemia w ere defined as risk factor conditions. Mean values for a series of ris k factor variables were compared between reference subjects (no risk f actors) and those with a risk factor condition (either one condition o nly, or in combination with one or more others). Prevalence estimates for each risk factor condition in combination with three or more other conditions were three to four times greater than expected by chance, and levels of risk factors for subjects with more than one risk factor condition were further away from the reference levels than for those with just one condition. Fasting and 2-h serum insulin levels were ele vated for each condition when in combination with others, or to a less er extent when isolated. However, this was not the case for isolated h ypertension where insulin levels were not elevated. When adjusted for age, sex, and body mass index, insulin levels were only significantly elevated in subjects with upper-body obesity if in association with ge neral obesity. A clustering of cardiovascular risk factors was therefo re found in Mauritius. However, insulin levels although high for most conditions were not high in hypertension.