Left ventricular mass and incident hypertension in individuals with initial optimal blood pressure: the Strong Heart Study

OBJECTIVE: Metabolic abnormalities have been shown to predict 8-year incident arterial hypertension in individuals with optimal blood pressure. As echocardiographic left ventricular mass has also been reported to predict incident hypertension in individuals with baseline blood pressure of less than 140/90 mmHg, we determined whether left ventricular mass predicts 4-year incident hypertension also in individuals with initial optimal blood pressure (<120/80 mmHg), independent of metabolic factors influencing blood pressure. METHODS: We studied 777 of 3257 members of the American Indian population-based Strong Heart Study cohort with optimal blood pressure (34% men, 45% obese, and 35% diabetic), aged 57 +/- 7 years, and without prevalent cardiovascular disease. RESULTS: Over 4 years, 159 individuals (20%, group H) developed hypertension (blood pressure >/=140/90 mmHg). They had a greater baseline BMI, waist girth, and blood pressure (112/69 vs. 109/68 mmHg, all P < 0.03) than those remaining normotensive (group N), with similar lipid profile and renal function. At baseline, left ventricular mass was significantly greater in group H than in group N (P < 0.004). The difference in left ventricular mass was confirmed after controlling for initial BMI, systolic blood pressure, homeostatic model assessment index, and diabetes. The probability of incident hypertension increased by 36% for each standard deviation of left ventricular mass index (P = 0.006), independent of covariates. Participants with left ventricular mass of more than 159 g (75th percentile of distribution) had 2.5-fold (95% confidence interval, 1.4-3.6; P < 0.001) higher adjusted risk of incident hypertension than those below this value. CONCLUSION: Left ventricular mass predicts incident arterial hypertension in individuals with initially optimal blood pressure. This association is independent of body build, prevalent diabetes, and initial blood pressure.