Seasonal (circannual) periodicity of spontaneous intracerebral hemorrhage in minnesota

Background and Purpose: Seasonal variation in the incidence of cerebral hemorrhage has been previously demonstrated. In this study, we sought to identify the climatological data best correlated with this seasonal variation.Methods: In a retrospectively studied sequential series of 236 patients with nontraumatic cerebral hemorrhage observed in Brussels over a period of 8 years, we cumulatively grouped the dates of stroke occurrence into a single calendar year.Results: We found marked seasonal variation in incidence, with the highest value (23%) observed in November-December and the lowest (10%) in July-August Seasonal variations in incidence of cerebral hemorrhage were shown to be correlated not only with the inverse of ambient temperature, but also with the inverse of hours of sunshine and with ambient humidity. We found no difference between hypertensive and normotensive patients.Conclusions: Our study fails to bear out the hypothesis that the higher incidence of cerebral hemorrhage in late autumn and winter is due to the influence of low ambient temperature on blood pressure. (Stroke 1992^3:24-27)

Section: »-O >H Time (2-month Penods)contrasting

confidence: 58%

Seasonal variation of cerebral hemorrhage in 236 consecutive cases in Brussels.

Capon

Demeurisse

1992

“…The number of patients varied widely, and not all series were large enough to have the statistical power for reliable conclusions. 1,5,[11][12][13][14]16,[31][32][33][34][35][36] The diagnosis of ICH was confirmed by imaging studies or autopsy in a few studies, 2,6,13,15,32,33,37,38 and it is often unclear whether ICH was spontaneous or primary. 3-5,8 -12,14 -16,31-34,39,40 In some studies, cases were identified on the basis of International Classification of Diseases (ICD) discharge codes, 8,9,10,39 whereas others included subarachnoid hemorrhage (SAH) 32 or excluded elderly patients.…”

Section: Discussionmentioning

confidence: 99%

“…3-5,8 -12,14 -16,31-34,39,40 In some studies, cases were identified on the basis of International Classification of Diseases (ICD) discharge codes, 8,9,10,39 whereas others included subarachnoid hemorrhage (SAH) 32 or excluded elderly patients. 13 Among studies on the seasonal distribution of ICH, some found increased occurrence of ICH [1][2][3][4][5][6][7][8][9][10]13 in winter, whereas others indicated peaks in other seasons 11,14,37 or no significant seasonal variation at all. 16,[31][32][33][34][35]38,39 However, the most consistent seasonal variation described was a seasonal pattern with a peak of incidence in winter and a minimum in summer.…”

Section: Discussionmentioning

confidence: 99%

“…Intracerebral hemorrhage (ICH) seems to occur more frequently during the winter months [1][2][3][4][5][6][7][8][9][10] and during the morning waking hours. 7,[11][12][13][14][15][16] Seasonal and diurnal blood pressure variations have been considered a possible explanation for these patterns of onset.…”

Section: S Tudies Of Temporal Variations In Cerebrovascular Eventsmentioning

confidence: 99%

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Differing Temporal Patterns of Onset in Subgroups of Patients With Intracerebral Hemorrhage

Passero

Reale

Ciacci

et al. 2000

Background and Purpose-The purpose of this study was to further analyze the temporal patterns of onset of intracerebral hemorrhage (ICH) and to determine whether or not subgroups with specific clinical characteristics exhibit different patterns of onset. Methods-The daily, weekly, and yearly variations in occurrence of ICH together with the relationship between ICH occurrence and changes in air temperature were evaluated in 1018 patients. Patients were grouped according to the presumed etiology of ICH: hypertensive ICH, secondary ICH, and ICH of undetermined origin. The contribution of demographic and clinical factors to the temporal distributions of ICH was also evaluated. Results-Marked differences in seasonal and diurnal patterns of ICH onset were observed in the different groups. The incidence of hypertensive ICH reflected seasonal and circadian changes in blood pressure, whereas the latter did not seem related to the onset of nonhypertensive ICH. The seasonal pattern was more evident in elderly patients with hypertensive ICH than in younger subjects. No significant weekly variations were observed; however, risk was greater on Monday in the working population. Conclusions-Our results suggest that the higher incidence of ICH in the colder months is due to the effect of low temperatures on blood pressure and that the clustering of ICH events in the morning is due to the increase in sympathetic tone, and consequent increase in blood pressure, on awakening. (Stroke. 2000;31:1538-1544.)

“…29 We did not find a seasonal periodicity in the occurrence of ICH or SAH. The study of patients in climates less severe than Minnesota 24 or Iowa 28 may have minimized seasonal effects on the incidence of intracranial hemorrhage.…”

Section: Discussionmentioning

confidence: 99%

Circadian rhythmicity of stroke onset. Intracerebral and subarachnoid hemorrhage.

Sloan

Price

Foulkes

et al. 1992

Our purpose was to describe and further understand the determinants of the time of onset of parenchymatous intracerebral hemorrhage and subarachnoid hemorrhage in patients enrolled in the Stroke Data Bank. We analyzed the observed times of onset of intracerebral hemorrhage (n = 237 patients) and subarachnoid hemorrhage (n = 243 patients) compared with expected times of onset if the probability of onset was constant across all time intervals. We also analyzed the role of clinical features (if any) in explaining the findings. For intracerebral hemorrhage, 52.5% of patients reported onset times between 0600 hours and 1400 hours, with peak onset between 1000 and 1200 hours (chi 2 = 62.94, df = 11, p less than 0.001). Patients with subarachnoid hemorrhage were more likely to lack a history of hypertension compared with patients who had intracerebral hemorrhage (chi 2 = 23.3, df = 1, p less than 0.001). Patients with subarachnoid hemorrhage were more likely to have more uniform onset time throughout the day (chi 2 = 12.92, df = 7, p = 0.074). However, subarachnoid hemorrhage patients with a history of hypertension were more likely to have peak onset times in mid-to-late morning compared with patients without such a history (chi 2 = 35.25, df = 10, p less than 0.001). The nonuniformity of onset times for intracerebral hemorrhage persisted even if patients with unknown onset times were treated as through their onset times were randomly distributed between 0000 and 0800 hours. Seasonal periodicity and the relation between initial systolic or diastolic blood pressure and time of onset for either type of hemorrhage were not observed. Our data suggest that the time of onset for both intracerebral hemorrhage and subarachnoid hemorrhage patients with a history of hypertension is similar to the diurnal variation in blood pressure.