A research team from Tokyo Science University found that the risk of emergency hospital admissions for stroke increases during the week following a typhoon.
This discovery highlights a critical window of vulnerability for the population during extreme weather events. Because stroke is the fourth leading cause of death in Japan [6], understanding these environmental triggers could improve emergency preparedness and patient outcomes.
The study analyzed approximately 850,000 patient records [1]. The data focused on the period following Typhoon No. 6, which made landfall on the Japanese archipelago on June 3, 2024 [5]. Researchers measured the stroke risk for the seven days immediately following the landfall.
Among the emergency admissions recorded during this timeframe, 13.1% were cases of intracerebral hemorrhage [2], and 9.4% were subarachnoid hemorrhages [3]. The research indicates that the risk is not uniform across the country. The greatest increase in admissions was observed in Okinawa, where the risk was about nine times higher than in Hokkaido [4].
Scientists said the spike in strokes is linked to rapid drops in atmospheric pressure that occur during a typhoon [8]. These pressure changes are thought to trigger physiological responses in the body that increase the incidence of stroke.
Japan faces a significant public health burden from these events, with over 100,000 annual deaths attributed to stroke [7]. While Typhoon No. 6 also caused physical infrastructure damage — including 149 buildings with floor-level flooding [6] — the research suggests the atmospheric impact poses a separate, systemic health threat.
The Tokyo Science University team said these findings alert the public and medical providers to the delayed health risks that persist after the storm winds have subsided.
“the risk of emergency hospital admissions for stroke increases during the week following a typhoon”
The correlation between atmospheric pressure drops and stroke incidence suggests that the health dangers of typhoons extend beyond immediate physical trauma or flooding. By identifying a specific high-risk window and geographic hotspots like Okinawa, health officials can implement targeted warnings and increase hospital staffing in the week following a storm to mitigate the impact of these environmental triggers.
