Apolipoprotein H levels in diabetic subjects: correlation with cholesterol levels

To assess the relationship between apolipoprotein H (apo H) plasma levels and lipid metabolism in diabetes mellitus, we have examined the correlation between apo H plasma concentration and the main plasma lipid levels in 127 non-insulin-dependent (NIDDM) and 118 insulin-dependent (IDDM) diabetes mellitus patients. The data are compared with those in 286 nondiabetics. Our data show a significant increase in plasma apo H in diabetic as opposed to nondiabetic subjects (NIDDM, 29.9 +/- 10.8 mg/dL; IDDM, 31.3 +/- 9.9; controls, 22.5 +/- 7.7; F = 53.3, P = .0001). The relation between plasma lipids and apo H was simultaneously evaluated in the three groups with inclusion of diabetes, sex, body mass index (BMI), and age as covariates in the model. This analysis showed a strong positive correlation (P = .0009) between apo H and total cholesterol, and a weaker positive correlation with triglycerides ([TGs] P = .016). The correlation between apo H and hemoglobin A1c (HbA1c) levels in diabetics (P = .03) highlights the importance of glycemic control for plasma levels of this apoprotein, which is highly glycated. Although the role of apo H in lipid metabolism is still uncertain, recent investigations on the possible relation between plasma apo H levels and increased plasma lipids and thrombotic risk could explain the increased atherosclerotic risk in diabetic patients.