Inflammation, obesity and cardiovascular function in African and Caucasian women from South Africa: the POWIRS study

Abstract

The integrated relationship between inflammation, obesity and cardiovascular disease is currently a subject of much research interest. These specific relationships, however, have not been studied in-depth in South African population groups in order to determine the role of ethnicity. It is known that Africans, compared to Caucasians, suffer from a high prevalence of hypertension. It was therefore hypothesized that the levels of inflammatory markers (high-sensitivity C-reactive protein (hsCRP), fibrinogen and leptin) are higher in Africans compared to Caucasians and are notably associated with cardiovascular dysfunction in Africans. Apparently healthy African (N ¼ 102) and Caucasian (N ¼ 115) women, matched for age and body mass index (BMI), were recruited. Leptin, hsCRP, fibrinogen and lipid levels, waist circumference (WC), BMI, systolic and diastolic blood pressure, cardiac output (CO), total peripheral resistance (TPR) and Windkessel compliance were measured. Results showed that the levels of leptin, hsCRP and fibrinogen were significantly higher (Po0.05) in the African women. The inflammatory markers correlated strongly with cardiovascular parameters, age and obesity (BMI, WC) in both groups, but after adjusting for age and obesity, none of the correlations were significant anymore. Multiple regression analyses (with leptin, hsCRP or fibrinogen as dependent variable) showed that only leptin levels of African women were explained by cardiovascular parameters (BP, TPR and CO). In conclusion, even though African women had significantly higher leptin, hsCRP, fibrinogen and blood pressure levels than Caucasian women, no cardiovascular parameters explained the variation in the inflammatory markers (except for leptin levels of African women).

Review: Metabolic Syndrome in Black South African Women

“…66,67 White women have lower leptin levels than Black BMI-matched African women, 68 indicating an ethnic variation in the production of this adipokine. 69 A positive association between leptin and blood pressure in Black South African women has been observed, 70,71 and leptin also correlates with total cholesterol levels. 72 Vitamin D deficiency has been associated with cardiometabolic diseases; however, the evidence is inconsistent.…”

Higher leptin levels in Asian Indians than Creoles and Europids: a potential explanation for increased metabolic risk

“…20 In South Africa, African women had higher levels of leptin than Caucasian women, especially when adjusted for waist circumference (WC). 21 A Chilean study showed lower leptin levels in Mapuche natives than Caucasians 22 and we have shown that…”

Obesity, inflammatory markers and cardiovascular disease: distinguishing causality from confounding

“…The current issue of the Journal of Human Hypertension features an article by Schutte et al 21 on the topic of inflammatory markers and obesity in South African Caucasian and Black women. The study population comprises 102 Black and 115 Caucasian women, who were individually matched for age and body mass index (BMI).…”

“…Inflammatory markers (leptin, high-sensitivity CRP and fibrinogen), obesity (BMI and waist circumference) and cardiovascular traits (blood pressures, triglycerides, high-density lipoprotein-C, cardiac output and total peripheral resistance) were measured, and the relationships between these factors assessed within and between ethnic groups. Schutte et al 21 conclude that the levels of inflammatory markers are higher in African women than in their Caucasian counterparts, even after adjustment for waist circumference. Furthermore, the relationships between inflammatory markers and cardiovascular outcomes are stronger in Black women compared with Caucasian women before adjustment for measures of obesity.…”

“…This latter observation is consistent with our own findings in prospective data in UK Caucasians. 22 A major limitation of studies such as Schutte et al 21 is that BMI and waist circumference may relate differently with the underlying phenotypes that they are intended to characterize, total adiposity and visceral adiposity, respectively. This issue has been studied in some detail in other ethnic groups.…”