REFERENCE VALUES FOR 24-HOUR AMBULATORY BLOOD-PRESSURE MONITORING BASED ON A PROGNOSTIC CRITERION - THE OHASAMA STUDY

Although reference values for ambulatory blood pressure (ABP) monitori ng have been investigated in several population studies, these values were derived from cross-sectional observations and were based merely o n the statistical distribution of blood pressure values. Therefore, we conducted a prospective cohort study to identify reference values for 24-hour ABP in relation to prognosis. We obtained measurements of 24- hour ABP for 1542 subjects (565 men) aged 40 years and over in a gener al population of a rural Japanese community and then followed-up their survival status. There were 117 deaths during the follow-up period (m ean, 6.2 years). The association between baseline 24-hour ABP values a nd mortality, examined by the Cox proportional hazards regression mode l adjusted for possible confounding factors, showed a better fit with a second-degree equation than with a first-degree equation. On the bas is of the results of this analysis, we identified the following refere nce values as the optimal blood pressure ranges that predict the best prognosis: 120 to 133 mm Hg for systolic blood pressure and 65 to 78 m m Hg for diastolic blood pressure. 24-Hour ABP values > 134/79 mm Hg a nd < 119/64 mm Hg were related to increased risks for cardiovascular a nd noncardiovascular mortality, respectively. This is the first report to propose reference values for 24-hour ABP based on a prognostic cri terion.