Association between tropical cyclone exposure and stroke hospitalization: A nationwide time-series analysis in Japan

Hisaaki Nishimura; Nobutoshi Nawa; Kiyohide Fushimi; Takeo Fujiwara

doi:10.1016/j.envint.2025.109906

Association between tropical cyclone exposure and stroke hospitalization: A nationwide time-series analysis in Japan

Environ Int. 2025 Nov:205:109906. doi: 10.1016/j.envint.2025.109906. Epub 2025 Nov 5.

Authors

Hisaaki Nishimura¹, Nobutoshi Nawa², Kiyohide Fushimi³, Takeo Fujiwara⁴

Affiliations

¹ Department of Public Health, Institute of Science Tokyo, Tokyo, Japan; Center for Well-being Research Advancement, Institute of Science Tokyo, Tokyo, Japan. Electronic address: nishimura.hlth@tmd.ac.jp.
² Center for Well-being Research Advancement, Institute of Science Tokyo, Tokyo, Japan; Department of Global Health Entrepreneurship, Institute of Science Tokyo, Tokyo, Japan.
³ Department of Health Policy and Informatics, Institute of Science Tokyo, Tokyo, Japan.
⁴ Department of Public Health, Institute of Science Tokyo, Tokyo, Japan; Center for Well-being Research Advancement, Institute of Science Tokyo, Tokyo, Japan.

PMID: 41213208
DOI: 10.1016/j.envint.2025.109906

Abstract

Background: Few studies have examined the association between tropical cyclone (TC) exposure and stroke hospitalization. This study aimed to clarify the association between exposure to TCs and emergency hospitalization for stroke.

Methods: Stroke hospitalizations were extracted from a nationwide administrative inpatient database for the period from May to October between 2011 and 2021. TC-exposed days were identified as those with TC-related peak sustained winds ≥ 15 m/s (30 knots). A time-series analysis was conducted to estimate the relative risks (RRs) of emergency hospitalization for stroke and its subtypes associated with TC exposure over lag 0-6 days.

Results: A total of 850,294 stroke hospitalizations were identified. TC exposure was associated with stroke hospitalization over lag 0-6 days (RR: 1.049 (95 % confidence interval (CI): 1.012-1.087)). On the day of exposure (lag 0 day), TC exposure was inversely associated with stroke (RR: 0.968 (95 %CI: 0.953-0.982)), while during lag 1-4 days, exposure to TCs was positively associated with stroke, with a maximum RR on lag 2 (1.031 (95 %CI: 1.023-1.038)). When stratified by stroke subtype, TC exposure was associated with hemorrhagic stroke (RR: 1.129, 95 %CI: 1.073-1.187), with increases in intracerebral hemorrhage (RR: 1.131, 95 %CI: 1.063-1.204) and subarachnoid hemorrhage (RR: 1.094, 95 %CI: 0.992-1.207), respectively. No TC-related increase in ischemic stroke was observed.

Conclusion: Exposure to TCs may increase the risk of stroke, especially hemorrhagic stroke.

Keywords: Climate change; Stroke; Tropical cyclone.

MeSH terms

Aged
Cyclonic Storms*
Environmental Exposure* / statistics & numerical data
Female
Hospitalization* / statistics & numerical data
Humans
Japan / epidemiology
Male
Middle Aged
Stroke* / epidemiology