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. / Graduation date: 1998

Indiana University-Purdue University Indianapolis (IUPUI) / Rates of chronic disease and physical inactivity are disproportionately high among African American women. Despite the known benefits of physical activity and an increasing number of programs designed to increase activity, attendance rates to many exercise programs remain low. There is much to learn about program types, such as healthy lifestyle programs (HLP); individual factors, such as self-efficacy; and mediating variables that may influence exercise program attendance. An observational study design was used to compare exercise self-efficacy and attendance in a community-based exercise program in African American women who were enrolled in a HLP (N = 53) to women who were not (N = 27). Exercise program attendance was gathered across six months; demographics, self-efficacy and physical activity behaviors were assessed through surveys; and physiological variables (resting heart rate and blood pressure, height, and weight) and physical fitness (muscular strength and endurance and cardiovascular endurance) were measured at baseline. Descriptive statistics were used to describe participants and groups were compared using T-tests, chi-square and non-parametric statistics. Finally, mediation analyses were conducted using multiple regression models to assess self-efficacy as a potential mediator to exercise program attendance. Women who enrolled in this study were of low income (61% having an annual income less than $20,000), obese with a mean (standard deviation) body mass index (BMI) of 37.7 (7.6), pre-hypertensive with a mean (standard deviation) systolic blood pressure of 125.9 (14.4), and scored poorly and marginally on two fitness tests. On average, women reported being Moderately Confident in their ability to exercise regularly, yet had low attendance in the exercise program with a median number .5 days over six months and there were no significant differences in exercise self-efficacy (p = .23) or attendance in the exercise program between groups (p = .79). Additionally, exercise self-efficacy was not a mediating variable to program attendance. Women in this study had little discretionary income and several chronic disease risk factors, yet exercise program attendance was low even in those enrolled in a HLP. Identifying factors that increase exercise self-efficacy and factors that influence attendance beyond self-efficacy may help future program design and attendance.