Ethnic differences in low-density lipoprotein particle size in hypertensive adults

Background: Hypertensive African Americans have higher rates of coronary heart disease (CHD) than their non-Hispanic white counterparts, despite having higher high-density lipoprotein cholesterol (HDL-C) levels and lower triglyceride levels. Objective: The goal of the present study was to assess whether low-density lipoprotein (LDL) particle size, a correlate of the above lipid traits and a risk factor for CHD, differs between hypertensive African Americans and whites. Methods: Participants included 1,177 hypertensive African Americans from Jackson, MS (60 ± 7 years, 72.4% women) and 860 hypertensive whites from Rochester, MN (58 ± 7 years, 56.7% women). LDL particle size was measured by polyacrylamide gradient gel electrophoresis. Within each gender, we assessed whether ethnicity was significantly associated with differences in LDL particle size after adjustment for CHD risk factors (age, total cholesterol, HDL-C, triglycerides, systolic blood pressure, diabetes, history of smoking, body mass index), statin use, and estrogen use (in women), and lifestyle variables (physical activity and alcohol intake). Results: Although HDL-C levels were higher and triglyceride levels lower in African Americans, LDL particle size (adjusted for CHD risk factors) was lower (P < 0.0001) in African-American men and women than in their white counterparts (mean ± SD; men, 267.6 ± 5.2 Å vs 270.2 ± 4.8 Å; women 268.7 ± 5.1 Å vs 271.3 ± 5.1 Å). In both genders, African-American ethnicity was associated with lower LDL particle size after adjustment for CHD risk factors, statin use and estrogen use (in women), as well as physical activity and alcohol intake. Conclusion: Hypertensive African-American men and women have lower LDL particle size than their white counterparts, despite having higher HDL-C and lower triglycerides.