Hypertension in Blacks

Abstract

The excess of hypertension among blacks has been recognized since early in this century and explains a substantial portion of the black health disadvantage. In a cohort study begun in the 1970s, hypertension accounted for 20% of all-cause mortality among blacks, compared to 10% among whites. National data on trends in hypertension (140/90 mm Hg or treatment) prevalence from 1960 to 1990 suggest a decline from 44% to 32%, although differences in survey technique likely account for this pattern. During this period the prevalence ratio of black:white remained constant at 1.5, suggesting that secular trends in causal factors, if any, effected both groups equally. Recent data demonstrate a gradient in risk across the African diaspora, with standardized prevalences of 14% in West Africa and 26% in the Caribbean, compared to 33% in the US. This pattern parallels the gradient in known risk factors, with obesity alone accounting for a third of the excess in the US compared to Africa. Why the black excess of hypertension in the US? Despite widespread speculation, unique characteristics of hypertension among blacks have yet to be established. Consistent evidence demonstrates a similar impact of the known risk factors in all population groups. Epidemiologic evidence likewise suggests that a similar risk of complications exists with blood pressure elevation among blacks and whites, level for level. Although the genetic epidemiology of hypertension is still in its infancy, no clear cross-population differences are yet apparent. Pathophysiologic traits that are known to be part of the causal etiologic pathway have not been shown to vary across groups. Unique features of this condition among blacks are likely to be restricted to the different mixes and intensities of risk factors. In the absence of evidence to support the hypothesis, it is perhaps surprising that credence continues to be given to the notion of black exceptionalism. Am J

Body mass index, abdominal adiposity and blood pressure: consistency of their association across developing and developed countries

“…In particular, this gradient was observed in black communities across Western Africa, the Caribbean Islands and the United States 6,7 to such an extent that, in the latter country, hypertension has been found to be more widespread among black people than among white people. 8 These observations have raised the possibility that the populations of developing countries, or at least those of African origin, have a higher susceptibility of blood pressure (BP) to excessive adiposity than Western populations and will be more severely affected, particularly in terms of hypertension-driven cardiovascular morbidity and mortality, by the current global upward trend in obesity. 9,10 This assumption has to be tested against the background of existing knowledge about the hypertensive effect of obesity.…”

Saphenous Vein Endothelin System Expression and Activity in African American Patients

“…1,2 These differences in the development and progression of hypertension in blacks have been proposed to be related to abnormal hemodynamic reactivity characterized by increased peripheral vascular resistance and diminished vasodilatation in response to environmental stress. 3 In a previous study, we found that plasma levels of the potent vasoconstrictor endothelin (ET)-1 were significantly higher in a black hypertensive group than in white hypertensive and white and black normotensive groups.…”

Hypertension in Black Patients

“…[1][2][3][4] Furthermore, the disease onset is earlier, and the consequences of hypertension, which include heart failure, myocardial infarction, stroke, and renal failure, are more pronounced in black patients. 1,5 These racial differences in the development and clinical course of hypertension have been attributed to environmental and physiological factors.…”