Diurnal variation in incidence of stroke: Oxfordshire community stroke project.

Abstract

Abstractexamined data from a community based stroke register Objective-To determine whether diurnal varia-in which the type of stroke was determined in 90% of tion occurs in the onset of stroke.cases.Design-Community based study over four years. Setting-Oxfordshire, United Kingdom. Subjects-105 000 people, of whom 675 had a first Patients and methods ever stroke. 545 had a cerebral infarction, 66 hadThe Oxfordshire community stroke project is a primary intracerebral haemorrhage, 33 had sub-prospective, community based study of first ever arachnoid haemorrhage, and in 31 the type of stroke stroke in a defined population of about 105 000 people was not known.in Oxfordshire. Definitions of type of stroke and Main outcome measures-Time of stroke and details of the methods used in the project are given degree of activity at onset.elsewhere.910 Six hundred and seventy five cases of Results-In the 578 patients for whom it was clinically definite first ever stroke were registered over known whether onset occurred while asleep or four years. Complete case ascertainment was obtained awake, the proportion with onset during sleep was through the collaboration of general practitioners and 25% (135/545) for cerebral infarction, 17% (11/66) for examination of hospital admission registers, the primary intracerebral haemorrhage, and 0% (0/33) Oxford record linkage system, and death certificates. for subarachnoid haemorrhage. This difference per-Most patients (614) were seen by a neurologist in the sisted if patients in whom it was not known whether study at a median time of four days after the onset of they were asleep or awake at onset were classed as symptoms, and a witness was interviewed when no asleep. For all stroke types together there was a history was available from the patient.In all, 574 had computed tomography or a postwith a morning peak between 0800 and 1000, which mortem examination. In the remaining patients the persisted even after allowing for strokes first noted type of stroke was determined with the Guy's Hospital on waking by redistributing the hour of onset through diagnostic score."I Stroke type was classified as cerebral the preceding eight hours (x2=47, p<0001). infarction, primary intracerebral haemorrahge, or sub-A significant diurnal variation was also found in arachnoid haemorrahge (all cases of subarachnoid the onset of cerebral infarction (peak 0800-1000, haemorrhage were included in the study).'°Cerebral x2=208-4, p<O001 recorded accurately in retrospective studies.' to examine data for subarachnoid haemorrhage and Professor Warlow.To investigate the possibility that strokes occur primary intracerebral haemorrhage. Details of more often at certain times of the day and that different whether the patient was at rest or active when the BMJ 192; types of stroke have different circadian variation we stroke occurred were also recorded, as was ahistory of BMJ VOLUME 304 18 JANUARY 1992155.

Parallel morning and evening surge in stroke onset, blood pressure and physical activity

“…The same investigators found a similar evening peak in myocardial infarction onset determined by the creatine phosphokinase method, 1 and this was later confirmed in the Cardiac Arrhythmia Suppression Trial (CAST). 19 A secondary evening peak has also been reported for all types of stroke in a UK study, 5 for ischemic stroke in a US study, 20 and for fatal stroke in Japan. 21 Furthermore, the frequency of subarachnoid hemorrhages was shown to exhibit an evening peak.…”

“…[1][2][3][4][5] Speculations about underlying physiological factors include relationship to diurnal variations observed in the production of hormones such as cortisol, insulin, and catecholamines, as well as sympathetic tone affecting heart rate and blood pressure (BP), platelet aggregability, blood viscosity, and fibrinolytic activity. 6 -10 The abrupt change in physical activity on awaking and arising is believed to be the major determinant of the diurnal variation of most of the above factors.…”

Impact of Obesity on 24-Hour Ambulatory Blood Pressure and Hypertension

“…The same investigators found a similar evening peak in myocardial infarction onset determined by the creatine phosphokinase method, 34 and this was later confirmed in the Cardiac Arrhythmia Suppression Trial (CAST). 37 A secondary evening peak has also been reported for all types of stroke in a UK study, 38 for ischemic stroke in a US study, 39 and for fatal stroke in Japan. 40 Furthermore, the frequency of subarachnoid hemorrhages was shown to exhibit an evening peak.…”

“…34 Little attention has been drawn to a second peak in the incidence of cardiovascular events, which has been shown to occur in some studies late in the afternoon or early in the evening. [35][36][37][38][39][40][41][42] Muller et al 35 showed that there is a second peak in the incidence of sudden cardiac death at Ϸ6:00 to 7:00 PM. The same investigators found a similar evening peak in myocardial infarction onset determined by the creatine phosphokinase method, 34 and this was later confirmed in the Cardiac Arrhythmia Suppression Trial (CAST).…”

Subarachnoid Hemorrhage Incidence in the United States Does Not Vary with Season or Temperature

“…Circadian and seasonal variations in blood pressure, infection frequency, ethanol and tobacco use, and sedentary behavior, in addition to alteration in blood pressure after strenuous exertion in colder climates, have all been proposed as mechanisms to explain seasonal variation in SAH. [26][27][28][29][30][31][32][33][34][35][36][37][38][39] Despite these well-established effects, the seasonal effects reported by some groups have not always been consistent with respect to timing, and other studies have failed to demonstrate any seasonal relationship. 23,24,[37][38][39][40][41][42] Thus, there remains no consensus regarding the influence of season and/or weather on the incidence rate of SAH.…”