# Longitudinal trajectories and risk factors of insomnia symptoms among Chinese bus drivers

## TL;DR

This study tracked insomnia symptoms in Chinese bus drivers over three years, identifying risk factors and patterns to help design better health interventions.

## Contribution

The study identifies distinct insomnia trajectories and their associated risk factors among Chinese bus drivers over three years.

## Key findings

- Insomnia symptoms decreased from 12.5% to 7.8% over three years.
- Five insomnia trajectories were identified, including chronic dysfunction and recovery patterns.
- Factors like job burnout and physical illness were linked to adverse insomnia outcomes.

## Abstract

This study investigated the three-year prevalence and longitudinal trajectories of insomnia symptoms among bus drivers and examined key sociodemographic-health-related factors and psychosocial predictors, with the aim of informing targeted preventive strategies.

A total of 11,576 bus drivers from 22 companies in Guangdong participated in three online surveys at T1 (August–December 2019), T2 (October–December 2021), and T3 (October–December 2023). The surveys assessed demographics, insomnia symptoms, and psychosocial factors. Two-stage multivariate logistic regression models were employed to examine risk factors associated with adverse trajectories.

Prevalence of insomnia symptoms declined steadily from 12.5% at T1 to 7.8% at T3. Five distinct trajectories were identified: resistance (78.5%), chronic dysfunction (1.9%), delayed dysfunction (4.7%), recovery (9.4%), and relapsing/remitting (5.5%). Sociodemographic and psychosocial distress factors (e.g., age, lower financial status, job burnout, family dysfunction) significantly increased the risk of general insomnia and adverse trajectory membership. Crucially, a history of severe physical illness was a strong determinant of chronic risk, while exercising for 30 min daily was significantly associated with a higher likelihood of recovery.

Our study offers insights into the longitudinal trajectories of insomnia symptoms and their associated risk factors among Chinese bus drivers. These findings carry important implications for designing trajectory-specific occupational health interventions and refining public transportation management strategies.