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

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.

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.

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.

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