Lipoprotein (a) concentrations and apolipoprotein (a) phenotypes in normoglycaemic relatives of type 2 diabetic patients

Lipoprotein(a) level and lipids in type 2 diabetic patients and their normoglycemic first-degree relatives in type 2 diabetic pedigrees

We investigated alterations of serum levels of Lp(a) and lipid profiles in type 2 diabetic patients and their normoglycemic first-degree relatives to evaluate the potential genetic association among these subjects. Serum Lp(a), triglycerride (TG), total cholesterol (TC), high density lipoprotein-cholesterol (HDL-C), and low density lipoprotein (LDL-C) levels were analyzed in 62 type 2 diabetic patients and 67 normoglycemic first-degree relatives from 29 type 2 diabetic pedigrees, and 45 healthy controls without family histories of diabetes. Dyslipidemia was observed in diabetics and their normoglycemic first-degree relatives. While higher serum TG levels were observed in both type 2 diabetics and their first-degree relatives than those in controls, higher TG levels in diabetics were found when compared with those in first-degree relatives. Meanwhile, lower serum HDL-C levels were observed in both type 2 diabetic patients and their first-degree relatives than those in controls. No significant difference of serum TC and LDL-C levels was found among the three groups. On the other hand, we did not observe significant differences of serum Lp(a) levels between type 2 diabetic patients and normoglycemic first-degree relatives, nor were any significant differences observed between diabetic patients and healthy controls (24.6+/-19.9 vs. 25.8+/-21.2, and 21.3+/-20.5 mg/dl). Although the average serum Lp(a) levels were similar in all subgroups, we did observe a positive correlation of Lp(a) between type 2 diabetic patients and their offspring (r=0.448, P<0.01), suggesting a potential genetic control for Lp(a) levels in type 2 diabetics families.

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

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 waist:hip ratio (p = 0.01) were independent predicators of apolipoprotein B concentrations while waist:hip 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.