Racial Differences in Blood Lipids Lead to Underestimation of Cardiovascular Risk in Black Women in a Nested Observational Study

Abstract

Background: During screening for enrollment in a clinical trial, we noticed potential racial disparities in metabolic syndrome variables in women who responded to our study advertisement. We designed a nested observational study to investigate whether metabolic syndrome variables differed between non-Hispanic blacks and non-Hispanic whites. Methods: The cohort comprised of women who have met the preliminary clinical trial criteria (body mass index [BMI] 25—45, age 20—75 years, and no use of lipid-lowering medications or supplements). These women, including 116 blacks and 138 whites, provided fasting blood samples for analysis of serum lipid profile. Results: Blacks had lower mean triglycerides (81.1 ± 3.3 mg/dL vs 140.6 ± 5.9 mg/dL; P < .0001), total cholesterol (176.1 ± 3.6 mg/dL vs 201.6 ± 3.3 mg/dL; P < .0001), and low-density lipoprotein (111.7 ± 3.3 mg/dL vs 128.2 ± 2.9 mg/dL; P < .001) and higher mean BMI (37.2 ± 0.5 vs 35.2 ± 0.5; P < .01) and diastolic blood pressure (82.4 ± 0.8 mmHg vs 79.4 ± 0.7 mmHg; P < .01) than whites. Only 7% of blacks, compared with 41% of whites, had triglycerides ≥150 mg/dL; as a result, fewer black women met metabolic syndrome criteria than white women. Additionally, in women with waist circumference ≥88 cm (N = 215), high-density lipoprotein was higher in blacks than in whites (48.3 ± 1.5 mg/dL vs 44.2 ± 1.3 mg/dL; P < .05). Conclusions: Due to racial differences in blood lipids, current metabolic syndrome criteria may result in underestimation of cardiovascular risk in blacks.