Objectives: To evaluate the influence of age on the day-night blood pressure rhythm and on the prevalence of vascular events in those whose systolic blood pressure (SBP) fell by <10% overnight (non-dippers).
Design: Cross-sectional observational cohort study.
Setting: Outpatient hypertension clinic.
Participants: 419 Hypertensive patients (214 male, 205 female).
Methods: All subjects were submitted to ambulatory blood pressure monitoring (Spacelabs 90207). The nocturnal fall of SBP was calculated from (day SBP--night SBP)/day SBP, where 'day' values were recorded between 0600 h and 2200 h and 'night' values between 2200 h and 0600 h. Dippers and non-dippers were divided in two subgroups according to age (under or over 65 years). Information on gender, smoking, diabetes mellitus and body mass index was collected and cerebrovascular and cardiovascular events, evaluated by history and medical records, were registered.
Results: The day-night difference in blood pressure significantly decreased with age and the prevalence of non-dippers was greater in elderly than in younger subjects (65.1% vs. 29.8%). No difference was found between groups for cerebrovascular events, irrespective of age. A relationship between non-dipping pattern and cardiovascular events was found only in younger hypertensive non-dippers (odds ratio, 2.0; 95% confidence interval, 1.20-3.21); in elderly people the prevalence of cardiovascular events was similar in dippers and non-dippers.
Conclusions: Cardiovascular risk is not increased in elderly non-dipper hypertensive subjects. This contrasts with results in younger populations.