Lipoprotein composition and serum apolipoproteins in normoglycaemic first-degree relatives of non-insulin dependent diabetic patients.

ABSTRACT

Cardiovascular disease is the leading cause of death in non-insulin dependent diabetes mellitus and first degree relatives of such patients are at increased risk of developing diabetes and cardiovascular disease. The aim of the present study was to determine whether lipid abnormalities occur in normoglycaemic relatives of non-insulin dependent diabetic patients. Cholesterol, triglycerides, apolipoprotein A-I and apolipoprotein B concentrations were measured in serum; the lipoprotein fractions very low density, intermediate density, low density and high density lipoprotein were prepared by sequential flotation ultracentrifugation and their composition investigated. The groups were matched for age, sex and blood glucose concentrations although the relatives (n = 126) were more insulin resistant as determined using the homeostasis model assessment method [1.9 (0.8-9.0) vs 1.6 (0.4-4.9) mmol/mU per l (mean [95% confidence intervals]); p < 0.001] and had greater body mass indices [26.6 (4.1) vs 24.8 (3.9) (mean [S.D.]); p = 0.001] than control subjects (n = 126). Relatives had higher serum apolipoprotein B concentrations than control subjects [0.9 (0.3) vs 0.8 (0.3) g/l, p = 0.02) and lower serum apolipoprotein A-I concentrations (1.4 (0.3) vs 1.5 (0.3), p = 0.02). In multivariate linear regression analysis of all subjects log insulin resistance (p = 0.0001), age (p = 0.002) and waisthip ratio (p = 0.01) were independent predicators of apolipoprotein B concentrations while waisthip ratio (p < 0.001) and smoking status (p = 0.002) were independent predictors of apolipoprotein A-I concentrations. Lipoprotein composition (measured in a subgroup of 76 control subjects and 88 relatives), serum cholesterol and serum triglyceride concentrations did not differ between the groups. We conclude that atherogenic apolipoprotein abnormalities occur in normoglycaemic relatives of non-insulin dependent diabetic patients.