-Original-

Influence of Seasonal Changes on Emergency Transports for Vertigo/Dizziness: A Study Based on Emergency Triage and Weather Factors

Makoto Suzaki¹, Masato Miyauchi^2,3, Naoto Matsuda¹, Asaka Onodera¹, Naoko Onodera¹, Masatoku Arai², Hideya Hyodo¹, Toshihiko Ohara¹, Masahiro Yasutake¹, Shoji Yokobori² and Gen Takagi¹

¹Department of General Medicine and Health Science, Nippon Medical School, Tokyo, Japan
²Department of Emergency and Critical Care Medicine, Nippon Medical School, Tokyo, Japan
³Department of Disaster and Emergency Medicine, Kochi Medical School, Kochi, Japan

Background: We investigated the association between the number of patients presenting to an emergency room (ER) with vertigo/dizziness (V/D) and seasonal variations, monthly trends, and weather factors.
Methods: We retrospectively investigated age, sex, cause of V/D, emergency triage level (Japan Triage and Acuity Scale), month, and seasonality among patients with V/D transported to the ER of Nippon Medical School between October 2014 and September 2017. We examined weather data, including monthly average precipitation and humidity, with respect to the number of patients with V/D.
Results: Among 706 patients with V/D, 481 presented with vertigo and 225 with dizziness. The mean age was 59±18 years and 66% were female. Regarding triage level, emergent (level 2) and urgent (level 3) cases accounted for 86% of cases and were more frequent in June-September (p=0.012). Regarding seasonality, 158 (22%), 195 (28%), 183 (26%), and 170 (24%) patients presented in spring, summer, autumn, and winter, respectively (p=0.744). The monthly number of V/D emergency transports tended to be higher between June and October and was significantly associated with average temperature (r=0.648, p=0.023), precipitation (r=0.655, p=0.021), humidity (r=0.676, p=0.016), and vapor pressure (r=0.648, p=0.023).
Conclusions: Although no apparent seasonality was observed in the monthly number of V/D-related emergency transports, the emergency triage level increased from the rainy season to early autumn. The monthly number of V/D cases transported by emergency services was significantly associated with average temperature, precipitation, humidity, and vapor pressure. These findings could inform public health policy and increase emergency preparedness.

J Nippon Med Sch 2025; 92: 268-278

Keywords
dizziness, emergency department, seasonality, vertigo, weather variation

Correspondence to
Makoto Suzaki, Department of General Medicine and Health Science, Nippon Medical School Hospital, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan
mstnndr1@nms.ac.jp

Received, November 2, 2024
Accepted, February 21, 2025