It has been known for many years that African Americans experience twofold higher rates of hypertension than do whites. The underlying biological mechanisms which lead to this differential are still not understood, however. Despite widespread speculation that persons of African descent are genetically susceptible to hypertension, few direct studies have been carried out. Rates of hypertension remain low in West Africa, and this study will provide a contrast between populations of similar genetic background in a low versus high risk environmental setting