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Published on: August 18, 2015
Daily Variation in the Occurrence of Different Subtypes of Stroke
Luciana Ripamonti1, Roberto Riva1,2, Fabiola Maioli3
1IRCCS Institute of Neurological Sciences, Bologna, Italy.
Insights
Stroke occurrence shows circadian variability, with more events during waking hours, especially in the morning, across various stroke types. Sex and clinical factors influence these diurnal patterns.
Area of Science:
- Neurology
- Circadian Biology
- Epidemiology
Background:
- Stroke exhibits complex onset patterns.
- Understanding circadian variability in stroke is crucial for risk stratification and prevention.
- Previous studies suggest diurnal variations in stroke incidence.
Purpose of the Study:
- To analyze circadian variability in stroke onset across different etiological subgroups.
- To investigate associations between stroke onset timing and various risk factors.
- To determine if stroke patterns differ between hemorrhagic and ischemic stroke types.
Main Methods:
- Retrospective analysis of 3,298 stroke patients admitted to a Stroke Unit.
- Categorization of strokes into hemorrhagic, large artery atherosclerosis, cardioembolic, small-vessel occlusion, and cryptogenic types.
- Statistical analysis of circadian onset patterns and correlations with risk factors (e.g., hypercholesterolemia, atrial fibrillation, hypertension, sex).
Main Results:
- Significant circadian variability in stroke onset was observed across all subgroups.
- Stroke was more frequent during waking hours than sleep, and in the morning versus the afternoon.
- Specific risk factors like hypercholesterolemia and atrial fibrillation were linked to waking onset in ischemic stroke.
- Hypertension was more prevalent in morning-onset small-vessel occlusion strokes.
- Male sex was associated with higher early morning occurrence in large artery atherosclerosis stroke.
Conclusions:
- Circadian patterns significantly influence stroke onset timing in both hemorrhagic and ischemic strokes.
- Diurnal variations, particularly morning predominance, are consistent across stroke types.
- Sex and specific clinical factors modulate the diurnal pattern of stroke occurrence.
Abstract:
Three thousand two hundred and ninety-eight patients admitted to our Stroke Unit with hemorrhagic, large artery atherosclerosis, cardioembolic, small-vessel occlusion, and undetermined etiology-cryptogenic strokes were included in the study. The circadian variability in onset in each stroke subgroup and the associations with various risk factors were analyzed. In each subgroup, a significant minority of patients suffered from stroke during sleep. In the ischemic group, hypercholesterolemia, paroxysmal atrial fibrillation, and previous myocardial infarction facilitated the onset during waking. During waking, stroke onset was significantly higher in the morning compared to the afternoon both in the hemorrhagic and in the ischemic type. In hemorrhagic stroke, a previous stroke was associated with a lower early morning occurrence. In large artery atherosclerosis stroke, males were at higher risk of early morning occurrence (p < 0.01). In small-vessel occlusion stroke, hypertension is significantly more present in the morning compared to the afternoon onset (p < 0.005). Circadian patterns of stroke onset were observed both in hemorrhagic and in ischemic stroke, irrespective of the ischemic subgroup. In all groups, stroke was more likely to occur during waking than during sleep and, in the diurnal period, during morning than during afternoon. Moreover, sex and some clinical factors influence the diurnal pattern.
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