Ambulatory Blood Pressure and Risk Factors for Coronary Heart Disease in Black and Indian Medical Students

Abstract

Background Coronary heart disease (CHD) has reached ‘epidemic’ proportions in South Africa. CHD is uncommon in the black population of South Africa, yet the prevalence of hypertension in the adult black population is high.

Design This study compared the blood pressure profile in 154 medical students of which 83 were Indians (I), 71 were black (B), 87 were male (50 I, 37 B), and 67 were female (33I, 34 B) age 21 (SD ± 1.6), using the cuff method and 24 h ambulatory blood pressure monitoring (ABPM).

Methods All students underwent ABPM. Biochemical studies for CHD risk factors were done. Electrocardiography (ECG) was performed in all participants and echocardiography in 90.

Results ABPM showed that black students had higher systolic and diastolic blood pressure throughout the day, night and critical time periods compared with the Indian students. Blood pressure load was higher in black (40.8%) than in Indian participants (29.6%; P < 0.05) and there was less dipping at night. Left ventricular mass was significantly higher in black than in Indian participants (29.6%; P < 0.05) and there was less dipping at night. Left ventricular mass was significantly higher in black than in Indian participants. Risk factors leading to CHD were more common in Indian than in black participants. Those with borderline hypertension (blood pressure ≥ 130/85 and ≤ 140/90 mmHg) had statistically higher serum triglyceride and left ventricular mass than normotensives.

Conclusions Young black people had higher blood pressure readings than young Indian participants in the absence of metabolic abnormalities and had greater cardiac involvement. Borderline hypertension is not innocuous. Metabolic risk factors for CHD in Indian people are apparent at an early age. This study emphasizes the need for prevention of risk factors leading to CHD at an early age.