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

Abstract

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 ¼ 102) and Caucasian (N ¼ 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 (Po0.01) 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.

A comparison of the cardiometabolic profile of black South Africans with suspected non-alcoholic fatty liver disease (NAFLD) and excessive alcohol use

“…Obesity is common among black South Africans, contributing to the onset of hypertension (Puoane et al, 2002;Schutte et al, 2008). Although obesity is associated with NAFLD, a study carried out in South Africa did not find any association between the degree of obesity and severity of NAFLD in Africans (Kruger et al, 2010), possibly due to the low number of Africans (N ¼ 12) used in their study.…”

Exploring the Link Between Cardiovascular Reactivity and End-Organ Damage in African and Caucasian Men: The SABPA Study

“…2 It has been found that the pulse wave velocity (PWV) of muscular arteries is higher in young Africans compared with Caucasians and that there are increased levels of vascular resistance during stress. 6,[13][14][15] Increased reactions to acute psychological stress challenges are implicated in cardiovascular disease: inter alia hypertension, carotid atherosclerosis, and cardiac hypertrophy. [16][17][18][19][20][21][22] It was reported that vascular resistance reactivity in Africans was positively associated with higher α1-adrenergic receptor density and therefore a higher serum calcium sensitivity.…”

Ethnic-Specific Associations between Abdominal and Gluteal Fat Distribution and the Metabolic Complications of Obesity: Implications for the Use of Liposuction

“…Two studies by Punyadeera et al (both in 2001), found that black women have significantly less VAT than white women. Despite such findings, Joffe et al (1994), Schutte et al (2008) and Seedat et al (1983) demonstrated that obese black Southern African women have double the prevalence of diabetes (7.0% vs. 3.6%) and hypertension (30% vs. 15%) compared to obese white women who are more commonly present with coronary heart disease and hypercholesterolaemia. This suggests that SAT volume in black women may be more strongly correlated with the development of IR than in white women.…”