Alterations of insulin secretion in familial combined hyperlipidemia

BACKGROUND: We have studied the abnormalities in glucose and insulin metabolism in a group of nondiabetic subjects with familial combined hyperlipidemia (FCH) in order to ascertain the contribution of metabolic risk factors to the elevated coronary heart disease incidence observed in FCH. PATIENTS AND METHODS: The study includes 42 non-diabetic subjects (25 male and 17 women, mean age 49.1 +/- 9.3 years), diagnosed with FCH by clinical and analytical studies of the probands and first degree relatives. Forty two control subjects of similar age, sex and body weight were also studied. In both groups plasma lipids and lipoproteins, plasma glucose and insulin basal and after oral glucose tolerance test (OGTT) were studied. RESULTS: The mean age, BMI and the separation by gender was similar in the two groups. The mean systolic and diastolic blood pressures were higher (p < 0.01) in the FCH group compared with controls (145.4/90.1 and 131.5/76.3 mmHg, respectively). The levels of lipids and ape B were also higher in the FCH group. The plasma glucose values were significantly higher at 30, 60, 90 and 120 minutes during OGTT and the plasma insulin at 0, 60, 90 and 120 minutes of OGTT in FCH respect to controls. The area under the curve of the secretion of insulin was 11652.0 +/- 2281.1 and 7205.4 +/- 2289.1 pmol/l/min in FCH and controls (p < 0.01), respectively. The percentage of subjects with basal hyperinsulinemia was 66.6% in the FCH group and 9.5% in the controls (p < 0.01); at 2 hours OGTT, 78.5% and 9.5% in FCH and controls, respectively (p < 0.01). The insulin secretion was significantly related with the plasma triglycerides levels, cholesterol bourded to very low density lipoproteins and systolic and diastolic blood pressure. CONCLUSIONS: Hyperinsulinism is a frequent finding in non-diabetic subjects with FCH, both with normal and abnormal glucose tolerance and could contribute to the high incidence of cardiovascular risk in these patients.