HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Correspondence: Submit a response Alert me when this article is cited Alert me when Correspondence are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Nyquist, P.A. Articles by O’Fallon, W.M. Search for Related Content PubMed PubMed Citation Articles by Nyquist, P.A. Articles by O’Fallon, W.M. Related Collections All Cerebrovascular disease/Stroke Intracerebral hemorrhage Subarachnoid hemorrhage All epidemiology

Circadian and seasonal occurrence of subarachnoid and intracerebral hemorrhage

From the Departments of Neurology (Drs. Nyquist, Brown, and Wiebers) and Health Sciences Research (Drs. Wiebers and O’Fallon, and C.S. Crowson), Mayo Clinic, Rochester, MN.

Address correspondence and reprint requests to Dr. Robert D. Brown, Jr., Mayo Clinic, 200 First Street SW, Rochester, MN 55905.

OBJECTIVE: To determine whether the time of onset of subarachnoid hemorrhage (SAH) or intracerebral hemorrhage (ICH) is associated with a time of day or season of year.

BACKGROUND: Prior studies have suggested that there may be a circadian and seasonal pattern of ischemic stroke occurrence, but this is less certain for hemorrhagic stroke. Population-based data have been unavailable.

METHODS: All incident ICH and SAH among residents of Rochester, MN, were ascertained. The medical records of patients were reviewed to determine the time of onset and date of occurrence. The day was divided into 8-hour periods, and the year into seasonal quartiles. Each patient was assigned a period based on the time of onset of symptoms. The data were analyzed by ² analysis to determine whether there was a trend toward increased occurrence based on time period or seasonal quartile of onset.

RESULTS: From 1960 to 1989, there were 155 cases (48 men, 107 women) of incident SAH. From 1975 to 1989, there were 137 cases (57 men, 80 women) of incident ICH. There was a significant increase in the time of onset for ICH and SAH in the 8 AM to 4 PM period (p = 0.005 and p = 0.03, respectively). The concomitant occurrence of hypertension, gender, and age did not affect the time of day of occurrence. In the analysis of seasonal variation, there was a significant increase in events during December, January, and February in the combined SAH and ICH group (p = 0.032) and a trend for SAH alone (p = 0.07) but not for ICH (p = 0.34). Hypertension and age had no impact on the association between season and the occurrence of SAH and ICH.

CONCLUSION: The occurrence of SAH and ICH is increased from 8 AM to 4 PM. The occurrence of hemorrhage is increased during the winter months, but this is likely limited only to SAH.

This article has been cited by other articles:

				S Omama, Y Yoshida, A Ogawa, T Onoda, and A Okayama Differences in circadian variation of cerebral infarction, intracerebral haemorrhage and subarachnoid haemorrhage by situation at onset J. Neurol. Neurosurg. Psychiatry, December 1, 2006; 77(12): 1345 - 1349. [Abstract] [Full Text] [PDF]

				C. A. Wauschkuhn, K. Witte, S. Gorbey, B. Lemmer, and L. Schilling Circadian periodicity of cerebral blood flow revealed by laser-Doppler flowmetry in awake rats: relation to blood pressure and activity Am J Physiol Heart Circ Physiol, October 1, 2005; 289(4): H1662 - H1668. [Abstract] [Full Text] [PDF]

				T. S. Field, M. D. Hill, and M. D. Connor Weather, Chinook, and Stroke Occurrence * Editorial Comment Stroke, July 1, 2002; 33(7): 1751 - 1758. [Abstract] [Full Text] [PDF]