Should obesity be blamed for the high prevalence rates of hypertension in black South African women?

• Published in: Journal of human hypertension Vol. 22; no. 8; pp. 528 - 536
• Main Authors: SCHUTTE, A. E, HUISMAN, H. W, VAN ROOYEN, J. M, SCHUTTE, R, MALAN, L, REIMANN, M, DE RIDDER, J. H, VAN DER MERWE, A, SCHWARZ, P. E. H, MALAN, N. T
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing 01.08.2008; Nature Publishing Group
• Subjects: Adult; African Continental Ancestry Group; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Blood Pressure - physiology; Body fat; Body Mass Index; C-reactive protein; Cardiology. Vascular system; Cardiovascular diseases; Clinical manifestations. Epidemiology. Investigative techniques. Etiology; Complications and side effects; Cross-Sectional Studies; Diagnosis; Female; Fibrinogen; Health aspects; Humans; Hypertension; Hypertension - ethnology; Hypertension - etiology; Inflammation; Insulin; Insulin resistance; Leptin; Lipids; Medical sciences; Middle Aged; Minority & ethnic groups; Obesity; Obesity - complications; Obesity - ethnology; Physical activity; Plasminogen activator inhibitors; Prevalence; Risk Factors; South Africa - epidemiology; Triglycerides; White people; Women; Young Adult; South Africa; Human; Hypertension; Obesity; Prevalence; Nutrition disorder; Negroid; Cardiovascular disease; Inflammation; Insulin; African; adipokines; insulin resistance; Nutritional status; women
• ISSN: 0950-9240; 1476-5527
• DOI: 10.1038/jhh.2008.35

Hypertension is highly prevalent in South Africa, resulting in high stroke mortality rates. Since obesity is very common among South African women, it is likely that obesity contributes to the hypertension prevalence. The aims were to determine whether black African women have higher blood pressures (BPs) than Caucasian women, and whether obesity is related to their cardiovascular risk. African (N=102) and Caucasian (N=115) women, matched for age and body mass index, were included. Correlations between obesity (total body fat, abdominal obesity and peripheral fat) and cardiovascular risk markers (haemodynamic parameters, lipids, inflammatory markers, prothrombotic factors, adipokines, HOMA-IR (homoeostasis model assessment insulin resistance)) were compared between the ethnic groups (adjusted for age, smoking, alcohol and physical activity). Comparisons between low- and high-BP groups were also made for each ethnic group. Results showed that African women had higher BP (P<0.01) with increased peripheral vascular resistance. Surprisingly, African women showed significantly weaker correlations between obesity measures and cardiovascular risk markers when compared to Caucasian women (specifically systolic BP, arterial resistance, cardiac output, fibrinogen, plasminogen activator inhibitor-1, leptin and resistin). Interestingly, the latter risk markers were also not significantly different between low- and high-BP African groups. African women, however, presented significant correlations of obesity with triglycerides, C-reactive protein and HOMA that were comparable to the Caucasian women. Although urban African women have higher BP than Caucasians, their obesity levels are weakly related to traditional cardiovascular risk factors compared to Caucasian women. The results, however, suggest a link with the development of insulin resistance.