The American journal of the medical sciences
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There is substantial evidence from both observational epidemiology studies and randomized controlled trials that dietary intake of sodium and potassium is important in the etiology of hypertension. However, the direct evidence for a direct link between dietary sodium and potassium and risk of cardiovascular and renovascular events is limited. ⋯ These studies should be focused on African Americans because they are at a disproportionately high risk of developing hypertension and blood pressure-related vascular disease. Moreover, this group has been underrepresented in most previous epidemiological studies.
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Review
The role of genetic and environmental factors in cardiovascular disease in African Americans.
Considerable interest has been focused over the years on estimating the relative importance of genetic and environmental factors on differences in rates of cardiovascular disease in blacks and whites. However, recent advances in molecular science have helped to illuminate the underlying complexity of this problem. Attempts to impute the genetic component from "what was left over" after control for a limited set of environmental exposures is increasingly recognized as naive. ⋯ Although it is obvious that blacks experience not only unique environmental exposures, such as white racism, but more intense exposure to common factors, such as obesity, current methods make it very difficult to summarize these effects. Simpler models, using data from large samples, could provide greater precision and might illuminate the exposure-outcome relationships common to all groups. Meanwhile, efforts to identify genetic underpinnings of complex disorders will have to reach a much higher level of development before useful conclusions can be reached about the magnitude and variation of effects between racial and ethnic groups.
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Although there is widespread recognition of a region with high stroke mortality in the southeastern United States that has persisted over the past 50 years (ie, the "stroke belt"), there is little agreement as to its underlying cause(s). Herein, we review data supporting 10 potential causes for the stroke belt, and assess: (1) the likelihood that each is the contributing factor to the excess mortality, and (2) areas of investigation where data are lacking and that require additional research efforts.
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Hypertension is the most common reversible risk factor for cardiovascular disease. It is especially common in African Americans. One of the factors that may contribute to the high rates of hypertension and target organ injury in African Americans is obesity. ⋯ Most research thus far has focused on blood pressure control systems studied in other forms of hypertension, including the sympathetic nervous system, the renin angiotensin system, and metabolic factors-primarily insulin resistance. Proposed mechanisms that are unique to obesity-associated hypertension include: 1) intrarenal physical forces associated with obesity-induced changes in the renal medulla; 2) genetic/metabolic factors; and 3) metabolic effects of abdominal visceral fat. The Jackson Heart Study provides a unique opportunity to address unresolved questions in the relationship of body weight, blood pressure, and cardiovascular disease.
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The Jackson Heart Study will be an epidemiological study of African Americans in Jackson, Mississippi, to identify risk factors for development and progression of cardiovascular disease. One of the potential risk factors to be assessed in this study is renal vascular disease. Atherosclerotic renal vascular disease is a disease of the elderly, is predominantly seen in white people, and is strongly associated with diffuse atherosclerotic disease and high-grade hypertensive retinopathy. ⋯ Diabetic patients fair less well with intervention and have a higher progression to end-stage renal disease or death. Obesity is not commonly seen in patients with renal vascular disease. The Jackson Heart Study may be able to assess the true incidence of atherosclerotic renal vascular disease in African Americans and its impact of cardiovascular morbidity and mortality.