Blood pressure in Navajo Indians and its association with type 2 diabetes and renal and cardiovascular disease.

In mid-1990 we evaluated blood pressure and its associations in 366 nondiabetic adult Navajos and 400 Navajos with type 2 diabetes attending Indian Health Service outpatient clinics in Tuba City, Arizona. In nondiabetics, systolic blood pressure (SBP) rose with increasing age while diastolic blood pressure (DBP) fell; 13.4% had hypertension by diagnosis or treatment. Female nondiabetics had lower blood pressures than males. SBP and DBP correlated with age, body mass index (BMI), and urinary albumin excretion (UAE). Hypertension was associated with a sixfold increase in nephropathy, a threefold increase in renal insufficiency, and an almost sixfold increase in cardiovascular disease. Diabetics had higher blood pressures than age- and sex-matched nondiabetics; 58.4% had hypertension by diagnosis or treatment, and, in spite of widespread antihypertensive treatment, blood pressures in almost 50% were suboptimal from the perspectives of cardiovascular and renal protection. Blood pressures of female diabetics were similar to those of males. Blood pressures correlated with age, BMI, and increasing UAE. Rates of nephropathy and cardiovascular disease were much higher in diabetics than nondiabetics, and within the diabetic population hypertension was associated with a greater than threefold increase in nephropathy, an eightfold increase in renal insufficiency, a five-fold increase in peripheral and cerebrovascular disease, and more than doubling of the rate of heart disease. The relationship of blood pressure to renal and cardiovascular disease suggest similar mechanisms in nondiabetics and diabetics, with diabetes contributing an accentuated susceptibility. Albuminuria and cardiac disease are generated at "subhypertensive" blood pressures, while established hypertension appears to drive overt renal, cerebrovascular, and peripheral vascular disease, and to further increase heart disease risk.(ABSTRACT TRUNCATED AT 250 WORDS)