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The article presents a study which describes the distribution of blood pressures, hypertension prevalence and associated risk factors among seven populations of West African origin. The higher rates of hypertension among persons of African descent in the U.S. compared with Whites has been recognized for most of this century. However, the underlying cause of this differential in risk remains one of the most perplexing biological questions in cardiovascular disease epidemiology. Despite considerable research and wide-spread speculation, the extent to which the steeper slope of blood pressure increase with age among U.S. In this paper the authors describe the pattern of hypertension prevalence determined through door-to-door surveys in Africa, the Caribbean, and the U.S., and they demonstrate the cross-cultural associations of hypertension with obesity and with sodium and potassium intake. To date, no direct comparisons of hypertension risk have been attempted between geographically separated Black populations to estimate the impact of known environmental factors. While these populations share a common genetic ancestry, they live under very different social and economic conditions. This makes it possible to examine the evolution of Black hypertension risk within a biological context not defined by reference to a separate ethnic group.

Coronary heart disease (CHD) is the leading cause of mortality in African Americans. To identify common genetic polymorphisms associated with CHD and its risk factors (LDL- and HDL-cholesterol (LDL-C and HDL-C), hypertension, smoking, and type-2 diabetes) in individuals of African ancestry, we performed a genome-wide association study (GWAS) in 8,090 African Americans from five population-based cohorts. We replicated 17 loci previously associated with CHD or its risk factors in Caucasians. For five of these regions (CHD: CDKN2A/CDKN2B; HDL-C: FADS1-3, PLTP, LPL, and ABCA1), we could leverage the distinct linkage disequilibrium (LD) patterns in African Americans to identify DNA polymorphisms more strongly associated with the phenotypes than the previously reported index SNPs found in Caucasian populations. We also developed a new approach for association testing in admixed populations that uses allelic and local ancestry variation. Using this method, we discovered several loci that would have been missed using the basic allelic and global ancestry information only. Our conclusions suggest that no major loci uniquely explain the high prevalence of CHD in African Americans. Our project has developed resources and methods that address both admixture- and SNP-association to maximize power for genetic discovery in even larger African-American consortia., Competing Interests: JBM has a research grant from GSK and a consulting agreement with Interleukin Genetics, SLH reports being listed as co-inventor on pending and issued patents held by the Cleveland Clinic relating to cardiovascular diagnostics. SLH reports having been paid as a consultant or speaker for the following companies: AstraZeneca Pharmaceuticals LP, BG Medicine, Merck & Co., Pfizer Takeda, Esperion, and Cleveland Heart Lab. SLH reports receiving research funds from Abbott, Liposcience, and Cleveland Heart Lab. WHWT reports receiving research grant support from Abbott Laboratories.