|Abstract or Summary
- Background: Premenopausal black women have a 2-3 fold greater rate of coronary heart
disease (CHD) than premenopausal white women. The purpose of this study was to
provide insight into the reasons for this difference.
Methods and Results: We compared CHD risk factors in 100 black and 100 white, healthy
premenopausal women age 18-45 years and of relatively advantaged socioeconomic status.
Black women consumed diets higher in saturated fat and cholesterol (12% of kcal as
saturated fat and 360 mg of cholesterol per day) than did white women (10% of kcal and
290 mg/day) (p=0.008). Black women also had a higher body mass index (BMI)
(32.0±9.2 vs. 29.0±9.4 kg/m², p=0.021), and higher systolic (124±17 vs. 115±14 mmHg,
p<0.0001), and diastolic (79±14 vs. 75±11 mmHg, p=0.048) blood pressures. The mean
plasma Lp(a) concentration was higher in the black women (40.2±31.3 mg/dl) than in the
white women (19.2±23.7 mg/dl)(p<0.0001). The black women, however, had lower
plasma triglyceride levels (0.91±0.46 vs. 1.22±0.60 mmol/L, p<0.0001), and a trend
toward higher HDL cholesterol levels (1.37±0.34 vs. 1.29±0.31 mmol/L, p=0.064) than
the white women. Plasma total and LDL cholesterol levels were similar. Rates of
cigarette smoking and alcohol intake were low and similar between the races.
Black women additionally had higher levels of plasma total homocysteine (8.80 vs.
7.81 μmol/L, p=0.013), lower plasma folates (3.52 vs. 5.23 ng/ml, p<0.0001), and higher
vitamin B₁₂ levels (522 vs. 417 pg/ml, p<0.0001) than white women. More white women
than black women took a multivitamin supplement (42.4% vs. 24.7%, p=0.019). When
adjusted for multivitamin use, homocysteine levels did not differ, but plasma folate
remained significantly lower in black women. Sixty-eight percent of black women carried
the wild-type methylenetetrahydrofolate reductase genotype, 32.0% were heterozygotes,
and none were homozygotes. Of the white women, 47.4% were wild-type, 40.3%
heterozygotes, and 12.3% homozygotes (p=0.013).
Conclusions: Premenopausal black women consumed more saturated fat and cholesterol
and had a higher mean body mass index, blood pressure, Lp(a), and plasma total
homocysteine levels than white women. These differences in coronary risk factors may
explain the higher incidence of CHD in premenopausal black compared to white women.