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.