Africa, Afro-Americans, and Hypertension: An Hypothesis

Abstract

Hypertension, or high blood pressure, affects nearly twice as many black Americans as white Americans, and with disproportionately more devastating effects. Black hypertension victims suffer kidney disease at up to eighteen times the rate of white victims, and have three to four times the fatal stroke rates (USPHS, 1980). Although no clear cause has surfaced for the overwhelming majority of hypertensive cases (Lancet, 1980; Gillum, 1979), there is mounting evidence that hypertension among blacks is related to sodium (salt) metabolism.It has long been believed that “excess” salt consumption elevates blood pressure (Kark and Oyama, 1980: 1007-1020; Ruskin, 1956:xiii). Today it is known that a high intake of salt can result in excess sodium retention, which can influence blood plasma volume, cardiac output, vascular resistance, and blood pressure (Williams and Hopkins, 1979). Blacks, however, apparently do not consume any more salt than whites (Luft et al., 1977). But, significantly, it would seem that blacks do have a tendency to retain much more sodium “on the same salt load” than whites (Luft et al., 1977). Moreover, the volume of blood plasma in blacks may be higher than in whites (Schacter and Kuller, 1984).