Weather conditions associated with subarachnoid hemorrhage: a multicenter case-crossover study

Abstract

Background Most spontaneous subarachnoid hemorrhages (SAH) occur unexpectedly and independently of classical risk factors. In the light of increasing climate variability and change, we investigated weather and rapid weather changes as possible short-term risk factors for SAH. Methods Seven hundred ninety one patients admitted to three major hospitals in Germany for non-traumatic SAH with a determinable onset of SAH symptoms were included in this hospital-based, case-crossover study. The effects of atmospheric pressure, relative air humidity, and ambient temperature and their 24 h changes on the onset of SAH under temperate climate conditions were estimated. Results There was no association between the risk of SAH and 24 h weather changes, mean daily temperature or mean relative air humidity in the overall population. For every 11.5 hPa higher mean daily atmospheric pressure, the risk of SAH increased by 15% (OR 1.15, 95% confidence interval (CI) 1.01–1.30) in the entire study population with a lag time of three days. Conclusion Our results suggest no relevant association between 24 h-weather changes or absolute values of ambient temperature and relative humidity and the risk of SAH. The medical significance of the statistically weak increase in SAH risk three days after exposure to high atmospheric pressure is unclear. However, as the occurrence of stable high-pressure systems will increase with global warming and potentially affect SAH risk, we call for confirming studies in different geographical regions to verify our observations.

Meteorological Variables Associated with Subarachnoid Hemorrhage: A Single Center Study

“…Increased SAH risk has been reported in correlation with increasing atmospheric pressure in different geographical regions [34][35][36][37][38][39][40] , while other studies report on an increased SAH risk associated with decreased atmospheric pressure 41 or even absence of association 25,27 . There is a significant number of published papers showing some kind of association between atmospheric pressure change and SAH incidence, probably because papers with negative results are rarely published, as pointed previously 31 . Furthermore, several authors speculate that atmospheric pressure may affect blood or intracranial pressure, leading to possible IA rupture 40,42 .…”

“…Furthermore, it was previously suggested and discussed that an additional possible risk factor of IA rupture and SAH could be seasonal or meteorological factors; some studies found that meteorological changes were associated with an increased incidence of SAH [18][19][20][21][22][23][24][25][26] , whereas others report absence of such association [27][28][29][30][31] . When observing and analyzing the data presented, the associations that have been observed appear to be conflicting.…”

Aneurysms in the Times of the Climatic Change

“…A study found that the incidence of subarachnoid hemorrhage was higher during the months characterized by higher temperatures and higher relative humidity. Specifically, the study reported that the risk of subarachnoid hemorrhage was higher by 39% in males on days with an increase in relative humidity by 17.6% [11]. It is possible that high humidity may increase blood pressure and promote the development of cerebral aneurysms, which could contribute to the increased risk of subarachnoid hemorrhage.…”

Several Risk Factors for Aneurysmal Subarachnoid Hemorrhage

“…M. Kockler и соавт. выявили слабую статистическую связь между повышением атмосферного давления и повышением частоты аневризматического САК через 3 дня [13].…”

“…в пятилетнем ретроспективном анализе не обнаружили влияния изменений температуры воздуха и колебаний атмосферного давления на частоту аневризматического САК, при этом выявили, что высокая влажность являлась статистически значимым фактором риска. Однако в ряде других исследований влияние влажности воздуха на риск разрыва ЦА не подтвердилось [3,4,6,13].…”