# Relationship Between Weather Conditions and Risk Factors for Cerebral Aneurysm Rupture in the Development of Subarachnoid Hemorrhage

## TL;DR

This study finds that sudden temperature drops are linked to an increased risk of cerebral aneurysm rupture in high-risk patients.

## Contribution

It identifies temperature fluctuations as a novel risk factor for aneurysm rupture in high-risk groups.

## Key findings

- Temperature differences were significantly larger in high-risk patients before aneurysm rupture.
- No significant associations were found between atmospheric pressure, precipitation, or seasons and SAH onset.
- Temperature drops appear to be a key weather-related factor in high-risk aneurysm rupture.

## Abstract

Introduction

Seasonal variations have been proposed as potential contributors to the risk of cerebral aneurysm rupture. The Unruptured Cerebral Aneurysm Study of Japan (UCAS Japan) score is a validated tool to assess the risk of aneurysm rupture, incorporating six factors: age, sex, hypertension, aneurysm size, location, and the presence of a daughter sac. Risk stratification is as follows: 0-3 (Risk I; 3-year rupture rate, 0.2%-0.9%), 4-5 (Risk II; 1.4%-2.3%), 6-8 (Risk III; 3.7%-7.6%), and ≥9 (Risk IV; ≥17%). This study investigates the association between meteorological conditions and the occurrence of subarachnoid hemorrhage (SAH) due to aneurysm rupture, with patients' risk levels categorized according to their UCAS Japan scores.

Methods

This study included 137 patients diagnosed with SAH who were admitted to our hospital between January 2014 and December 2023. Meteorological variables, including temperature, atmospheric pressure, and precipitation, were analyzed to examine their association with the onset of SAH.

Results

The temperature difference between one day before onset and the day of onset was significantly greater in Group IV compared to Group II (p< 0.05). Additionally, the temperature differences between the day of onset and 1, 2, and 3 days before onset were significantly larger in Group IV than in Group III (p< 0.01, p < 0.01, and p < 0.05, respectively). The temperature difference between the day of onset and 1, 2, and 3 days before onset was significantly larger in Group IV than in Groups I, II, and III (p < 0.01). No significant differences were observed among the groups in terms of atmospheric pressure, precipitation, or seasonal variation.

Conclusion

Temperature drops are associated with SAH onset in patients with high-risk aneurysms. This study highlights the importance of considering weather-related factors, particularly temperature fluctuations, when assessing the risk of aneurysm rupture. Further research is warranted to validate these findings.