Prognostic significance of night-time, early morning, and daytime blood pressures on the risk of cerebrovascular and cardiovascular mortality: the Ohasama Study.
OBJECTIVE
To clarify whether high blood pressure (BP) at a particular time of day is associated with cerebrovascular and cardiovascular mortality risk.


METHODS
Cerebrovascular and cardiovascular mortality in 1360 individuals aged 40 years and older in Ohasama, Japan, was followed for an average of 10.6 years. We used 2-h moving averages of the BP (a total of 24 average BP measurements for two consecutive hours based on four BP readings taken every 30 min) to compare the predictive power of BP taken during a 24-h period given the same number of measurements. The associations between cerebrovascular and cardiovascular mortality risk and the 2-h moving averages of systolic blood pressure (2 h-SBP) recorded over 24 h were analysed using a Cox proportional hazards model after adjusting for possible confounding factors.


RESULTS
The total cerebrovascular and cardiovascular mortality risk was significantly associated with elevated 2 h-SBP recorded during the night and early morning periods. Haemorrhagic stroke mortality was significantly associated with elevated daytime 2 h-SBP. Cerebral infarction mortality and heart disease mortality were significantly associated with elevated night-time 2 h-SBP.


CONCLUSIONS
High BP at different times of day were associated with different subtypes of cerebrovascular and cardiovascular mortality risk.
Metoki
Hirohito
H
Department of Clinical Pharmacology and Therapeutics, Tohoku University Graduate School of Pharmaceutical Sciences and Medicine, Sendai, Japan.
Ohkubo
Takayoshi
T
Kikuya
Masahiro
M
Asayama
Kei
K
Obara
Taku
T
Hara
Azusa
A
Hirose
Takuo
T
Hashimoto
Junichiro
J
Totsune
Kazuhito
K
Hoshi
Haruhisa
H
Satoh
Hiroshi
H
Imai
Yutaka
Y
D000328:Adult; D000368:Aged; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory / Q000379:methods*; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000401:mortality; D002561:Cerebrovascular Disorders / Q000175:diagnosis* / Q000401:mortality; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D018570:Risk Assessment; D020521:Stroke / Q000175:diagnosis; D013997:Time Factors