Body mass index and waist circumference predictors of cardiovascular risk in African Americans

The purpose of our study was to determine which measure of obesity is better at predicting cardiovascular risk in African Americans. We hypothesized that BMI alone would be significantly associated with cardiovascular reactivity. We also hypothesized that waist circumference alone would be significantly associated with cardiovascular reactivity. Lastly, we hypothesized that BMI and waist circumference together would be more associated with cardiovascular reactivity and account for more of the variance than the two measures alone.

BMI and waist circumference were measured in 105 African American college students (21 men and 84 women) aged 18-27. In addition, heart rate, cardiac output, stroke volume, and systolic and diastolic blood pressure were measured as the participants viewed a racially noxious scene on videotape.

BMI and waist circumference analyzed separately were significantly associated with stroke volume, cardiac output, and systolic blood pressure. These positive associations showed that heavier participants had higher systolic blood pressure and their hearts pumped out greater blood volume compared to their thinner counterparts. Body mass index also completely mediated the relationship between waist circumference and cardiovascular activity.

The findings may be attributed to the premise that the waist circumference standards are different for African Americans than for Whites. Future research should establish waist circumference thresholds that are better predictors of cardiovascular disease in African Americans.