SEASONAL VARIATIONS OF 24-HOUR AMBULATORY BLOOD PRESSURE AND BLOOD PRESSURE VARIABILITY IN THE YOUNG AND ELDERLY ESSENTIAL HYPERTENSIVE PATIENTS

Abstract

Objective: Seasonal blood pressure (BP) changes has been described in clinic BP. Few studies have examined the seasonal variation in BP and BP variability, assessed by 24-hour ambulatory blood pressure monitoring (ABPM) and it remains uncertain whether the seasonal trend differs between young and elderly hypertensive patients.

Design and Method: A total of 1028 untreated essential hypertensive patients (mean age 52 ± 14 years) who underwent 24-hour ABPM between January 2009 and April 2013 were enrolled. Patients were divided into young (age ≤ 70 years, n = 927) and elderly (age > 70 years, n = 101) groups.

Results: Compared to elderly group, young age group had higher clinic, 24-hour, daytime and night-time diastolic BP (DBP), higher clinic, 24-hour and daytime heart rate (HR), higher 24-hour and daytime HR variability (HRV), lower night-time systolic BP (SBP) and daytime SBP variability. In young age group, significant seasonal variation of clinic DBP and daytime SBP variability with a peak in autumn, and nighttime DBP and HR with a peak in spring and the increased prevalence of non-dippers in summer were observed. On the other hand, elderly group demonstrated seasonal variation of clinic, 24-hour, daytime and nighttime HR with a peak in autumn, daytime DBP with a peak in winter and night-time SBP variability with a peak in summer.

Conclusions: There was an apparent seasonal variation of DBP, HR and SBP variability in both young and elderly hypertensive patients. However, elderly patients showed more pronounced seasonal change in HR compared to younger patients.