Abstract
Aim: The goal of this study was to quantify the extent of possible day-to-day differences in 24-hour ambulatory blood pressure (ABP) monitoring results especially in association with age.
Method: A total of 514 community-dwelling subjects were initially recruited to participate in this study, and 450 subjects (average 58.8 years, 186 men and 264 women) had ABP monitoring for at least 6 days using an oscillometric monitor (TM-2430). We calculated the mean ABP and blood pressure (BP) dipping ratio for each day. Subjects were devided into 3 groups, 91 subjects aged from 40 to 49 years (average 41.8 years, younger group), 192 subjects from 50 to 64 years (average 57.5 years, middle-aged group), and 167 subjects over 65 years of age (average 69.5 years, elderly group). A mean ABP of >130/80 mm Hg was a criteria for hypertension (HT), and a decrease of less than 10% in BP during the night was defined as non-dipper. From the view point of day-to-day difference of ABP, 450 subjects were classified into (1) persistent normotension, masked ABP HT, intermittent ABP HT and persistent HT, and (2) persistent dipper, masked non-dipper, intermittent non-dipper and persistent non-dipper.
Results: Frequency of masked and intermittent ABP HT was higher in the elderly group than the younger or middle-aged groups (47.3% vs. 27.5% or 39.6%), and the frequency of masked and intermittent non-dippers was also higher in association with age (55.0%, 59.5%, 69.7%, p<0.01).
Conclusion: Aging can affect ABP variability. ABP monitoring should be used more precisely for the better diagnosis and treatment of HT in the elderly.
