Association of apolipoprotein B, LDL-C and vascular stiffness in adolescents with type 1 diabetes.

Abstract

LDL cholesterol (LDL-C) is the current lipid standard for cardiovascular disease (CVD)-risk assessment in type 1 diabetes. Apolipoprotein B (apoB) may be helpful to further stratify CVD risk. We explored the association between apoB and pulse wave velocity (PWV) to determine if apoB would improve CVD-risk stratification, especially in type 1 diabetes adolescents with borderline LDL-C (100-129mg/dL). We hypothesized that type 1 diabetes adolescents with borderline LDL-C and elevated apoB (≥90mg/dL) would have increased PWV compared to those with borderline LDL-C and normal apoB (<90mg/dL), and that apoB would explain more of the variability of PWV than alternative lipid indices. Fasting lipids, including apoB, were collected in 267 adolescents, age 12-19years, with diabetes duration >5years and HbA1c 8.9±1.6%. Triglyceride to HDL-C ratio (TG/HDL-C) and nonHDL-cholesterol (nonHDL-C) were calculated. PWV was measured in the carotid-femoral segment. ApoB, nonHDL-C and TG/HDL-C correlated with PWV (p<0.0001). ApoB, nonHDL-C and TG/HDL-C remained significantly associated with PWV in fully adjusted models. In adolescents with borderline LDL-C (n=61), PWV was significantly higher in those with elevated apoB than in those with normal apoB (5.6±0.6 vs. 5.2±0.6m/s, p<0.01) and also remained significant after adjustment for CVD-risk factors (p=0.0002). Moreover, in those with borderline LDL-C, apoB explained more of the variability of PWV than nonHDL-C and TG/HDL-C. Elevated apoB is associated with increased arterial stiffness in type 1 diabetes adolescents. Measurement of apoB in addition to LDL-C may be helpful in stratifying CVD risk in type 1 diabetes adolescents, especially in those with borderline LDL-C.