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Differentiation between Stroke Subtypes and the Causes of Monthly Variations: The Akita Stroke Registry
1Department of General Medicine, Saiseikai Utsunomiya Hospital, Japan.
Insights
Seasonal variations significantly impact stroke occurrence, particularly cerebral hemorrhage (CH). Lowering blood pressure (BP) is key for prevention, with a 5 mmHg reduction potentially decreasing CH risk by 35%.
Area of Science:
- Neurology
- Cardiology
- Public Health
Background:
- Stroke incidence exhibits seasonal patterns.
- Stroke is categorized into cerebral hemorrhage (CH), cerebral infarction (CI), and subarachnoid hemorrhage (SAH).
Purpose of the Study:
- To analyze stroke events by subtype and month.
- To identify key factors influencing seasonal stroke variations.
- To inform stroke prevention strategies.
Main Methods:
- Analysis of 58,684 stroke cases from the Akita Stroke Registry (1991-2010).
- Classification of stroke events by subtype and month of onset.
- Correlation analysis with monthly resting blood pressure and outdoor temperature data.
Main Results:
- Systolic blood pressure (BP) showed monthly variations.
- BP and outdoor temperature significantly correlated with hemorrhagic stroke events (CH and SAH).
- Cerebral hemorrhage (CH) displayed the most pronounced seasonal differences, with systolic BP as the primary influencing factor.
Conclusions:
- Lowering blood pressure is the most effective strategy for cerebral hemorrhage (CH) prevention.
- A 5 mmHg decrease in home BP may reduce CH risk by 35%.
- Physicians should guide patients in lowering BP year-round, especially during winter, through medication and lifestyle adjustments to mitigate cold stress impacts.
Abstract:
Objective It has been established that stroke occurrence is influenced by seasonality. Stroke is divided into three subtypes: cerebral hemorrhage (CH), cerebral infarction (CI), and subarachnoid hemorrhage (SAH). The purpose of this paper was to analyze stroke events by subtype and month, in order to clarify the biggest factors that affect seasonal differences and thereby gain insight into stroke prevention. Methods Initial stroke events in the Akita Stroke Registry from 1991 to 2010 (58,684 cases; male 30,549, female 28,135) were classified by subtype and the month of onset, and correlations were estimated based on 115 healthy volunteers' monthly mean resting blood pressure (BP) at home and outdoor temperature measured by the Akita Meteorological Observatory in 2001. Results Systolic BP showed monthly variation in both morning and evening measurements. BP and outdoor temperature showed significant correlations with hemorrhagic stroke events by month (CH: r=0.87, r=-0.82; SAH: r=0.68, r=-0.82). Among the stroke subtypes, seasonal differences were the greatest in CH. Systolic BP was the most important factor for monthly and seasonal variation in stroke events. By comparing monthly BP variations with CH incidence throughout the year, we concluded that a decrease in home BP of 5 mmHg can reduce the risk of CH by 35%. Conclusion Our findings suggest that lowering BP would be the best strategy for CH prevention. Simple daily actions may be affected by cold stress. As physicians, we must strive to help patients lower their BP throughout the year not only with medication but with lifestyle guidance, especially in winter.
