# Trends in and Risk Factors for Bicycle-Related Mortality in an Ageing Cycling-Centric Country: Analysis of Japanese Administrative Data

## TL;DR

This study examines trends in bicycle-related deaths in Japan, finding that older cyclists face significantly higher mortality risks despite overall declining casualty rates.

## Contribution

The study identifies age-specific risk factors and trends in bicycle-related mortality in Japan's aging population using administrative data.

## Key findings

- People over 70 years old have more than 10 times the mortality risk of younger cyclists (IRR = 12.62).
- Casualty and mortality rates declined in all age groups until 2020, but lethality of collisions has not improved significantly.
- Current safety measures are ineffective for reducing bicycle-related deaths among older cyclists.

## Abstract

Japan has the most ageing population in the world with a high population of bicycle users, and the percentage of older cyclists continues to grow as the population ages. At the same time, the proportion of bicycle-related collisions is increasing. The aim of this study is to analyse trends and risk factors for bicycle injuries and deaths in Japan in order to suggest preventive measures, using data from vital statistics and the National Police Agency to calculate incidence rate ratios (IRR), age-standardised mortality rates, and annual percent changes, by ten-year-interval age groups. Data from the Japan Trauma Data Bank was analysed for demographic information about injuries. The risk of casualties was high in the younger generation and lower in the older population. However, the risk of mortality increased rapidly with age, with people over 70 years old facing more than 10 times the risk of younger age groups (IRR = 12.62). Casualty and mortality rates were declining in all age groups until the year 2020 (range: −9.77% to −4.95%, −8.61% to −1.07%, respectively). However, lethality of bicycle collisions showed no significant reduction. Current methods have not been effective in reducing bicycle-related lethality in Japan, especially for the older population, and should be improved to ensure that bicycle transportation is safe for all road users.