Single risk factor intervention may be inadequate to inhibit atherosclerosis progression when hypertension and hypercholesterolemia coexist.

A pproximately 25% of the US population has / \ hypertension as defined by blood pressure A . \ levels equal to or greater than 140/90 mm Hg. A similar percentage has hypercholesterolemia with plasma cholesterol concentrations exceeding 240 mg/dl. In addition to their high prevalence, these two risk factors coexist in greater than expected frequency. Hypercholesterolemia occurs in approximately 40% of hypertensive individuals, and hypertension is present in 46% of hypercholesterolemic subjects. This high rate of coexistence is due in part to the increased prevalence of both risk factors in obese subjects. Genetic factors also appear to be involved: 12% of hypertensive subjects less than 60 years of age exhibit the syndrome of familial dyslipidemic hypertension. Furthermore, combined abnormalities in both risk factors can induce markedly increased rates of atherogenesis and all of the clinical complications of atherosclerosis. Despite these impressive statistics, limited information is available regarding the mechanisms by which hypercholesterolemia or hypertension, or both, cause atherosclerosis and whether modification of either or both of these risk factors will reduce atherosclerotic disease and its complications.