Title: Why Do Black Americans Have Higher Prevalence of Hypertension? | Hypertension
Headings: Why Do Black Americans Have Higher Prevalence of Hypertension?
Why Do Black Americans Have Higher Prevalence of Hypertension?
An Enigma Still Unsolved
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Content: Kaplan and Victor 3 listed 18 genotypes and intermediate phenotypes that were implicated with an increase of blood pressure in blacks. A higher sensitivity to alcohol could be added to that list. 4 Some of these mechanisms, such as a higher renal retention of sodium by blacks, are attractive. The “slavery hypertension hypothesis” states that the higher prevalence of hypertension among blacks could have resulted from an enhanced ability to conserve salt by slaves, protecting them from fatal salt-depletive diseases during the stormy Atlantic passage, such as diarrhea and vomiting. 5 This condition would induce hypertension when they and their descendants consumed the much higher sodium content in American compared with African foods. This hypothesis is hard to confirm or refute. The association between genetic traits and renal outcomes has been reported in black Americans versus white Americans. Kao et al 6 and Kopp et al 7 reported an association between a genetic variation of the MYH9 region on chromosome 22 with focal segmental glomerulosclerosis, a condition previously attributed to “hypertensive nephrosclerosis” and found much more frequently in black patients with end-stage renal disease than in whites with end-stage renal disease. The attributable risk for carriage of this MYH9 haplotype was found in 74% of blacks and in only 4% of whites with focal segmental glomerulosclerosis. More recently, using much more complete genomic sequences, Tzur et al 8 reported missense mutations in the APOL1 gene, which neighbors the MYH9 gene on chromosome 22 in patients with focal segmental glomerulosclerosis.