A Bayesian spatio-temporal analysis linking 12.9 million Japanese deaths (2010–2019) to population-weighted typhoon wind exposure found 2,426 cumulative excess deaths among adults 70 and older, with mortality spiking within 0–1 weeks of typhoon landfall. The effect was strongest in areas with limited healthcare access and higher natural hazard vulnerability. For under-70s, cumulative excess mortality was statistically uncertain (781 deaths; 95% CI: −309 to 1,900), though delayed mortality clusters emerged in lower-income and landslide-prone regions.
This preprint, not yet peer-reviewed, adds quantitative granularity to a recognized but undercharacterized public health problem. While typhoon mortality is broadly attributed to acute trauma and infrastructure disruption, this work distinguishes between immediate and delayed mortality pathways — a mechanistic distinction with real planning implications. The finding that healthcare access mediates elderly mortality risk aligns with post-disaster literature showing that hospital inaccessibility, medication interruption, and caregiver displacement elevate post-event mortality well beyond direct storm casualties. Japan's rapid demographic ageing makes this particularly urgent: as the 70-plus population expands, aggregate typhoon mortality burdens will grow even under stable climate conditions, let alone intensifying storm tracks projected under warming scenarios. The Bayesian credible intervals are wide, suggesting considerable spatial uncertainty; the analysis is also ecological and cannot establish individual-level causation. Still, the framework — integrating income, hazard geography, and healthcare infrastructure — offers a transferable model for climate-resilient health system planning across typhoon-exposed Asia-Pacific nations.
