Apolipoprotein B, ratio of total cholesterol to HDL-C, and blood pressure in abdominally obese white and black American women

Abstract

Objective: To compare the association of apolipoprotein B (ApoB) and total cholesterol to high-density lipoprotein cholesterol (TC/HDL) with blood pressure in abdominally obese white and black American women. We also sought to determine if there are ethnic differences in blood pressure values that could be explained by differences in mean values of ApoB and TC/HDL.

Methods: Data (n = 1844) from the Third US National Health and Nutrition Examination Survey were used in this study. Abdominal obesity was defined as waist circumference (WC) of ⩾88cm or having WC greater than what was expected as predicted from residuals obtained from linear regression of WC on BMI. Bi-variate Pearson’s correlation analysis was used to quantify the degree of association of ApoB and TC/HDL with blood pressure and other lipids. Multiple linear regression analysis was used to assess the independent contribution of ApoB and TC/HDL to blood pressure, adjusting for age, total cholesterol, alcohol intake, and smoking. To determine ethnic differences in blood pressure values associated with ApoB or TC/HDL, dummy variables were used to compare blacks with whites fitted in multiple regression models, while adjusting for age, total cholesterol, alcohol intake and smoking.

Results: Elevated ApoB was positively associated with diastolic and systolic blood pressure (DBP/SBP) in blacks and whites, independent of age, total cholesterol, alcohol intake and smoking (P < 0.01). Elevated TC/HDL was also positively associated with increased DBP and SBP in whites (P < 0.05). For the same value of ApoB and TC/HDL whites had higher values of DBP and SBP than blacks, adjusting for confounding variables.

Conclusions: Compared with TC/HDL, ApoB was more strongly associated with DBP and SBP in both abdominally obese white and black women. Since ApoB is associated with hypertension, the combination of elevated ApoB and hypertension may identify a group of patients with more marked risk of vascular disease, thus, warranting further investigation.