JMIR Publications

ABSTRACT

Background:

Japanese bus drivers face significant structural health risks due to irregular shift work. While Japan's "Specific Health Guidance" targets metabolic syndrome, the long-term trajectory from behavior change initiation to maintenance and physiological impact remains unclear in this high-risk population.

Objective:

This study aimed to identify factors promoting behavior change initiation, determine maintenance duration, and examine the impact of sustained changes on physiological markers among male bus drivers.

Methods:

We conducted a retrospective study using health checkup data (2006–2023) of 1,125 at-risk male bus drivers in Japan. The participants were classified according to their lifestyle modification stages using a Standard Questionnaire for Specific Health Checkups. Logistic regression was used to identify initiation predictors, survival analysis (Kaplan-Meier analysis) for maintenance duration, Bonferroni-corrected t-tests for physiological trajectories, and chi-square tests for lifestyle differences between the "Sustained" (maintained action) and "Comparison" (non-action) groups.

Results:

Among 1,125 at-risk participants (mean age 38.0 years), 147 transitioned to action stages, while 888 remained in the non-action stage (n = 1,035 for analysis). Predictors of initiation were older age (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.00–1.06, P = .046) and higher Composite Risk Scores (OR 1.22, 95% CI 1.00–1.49, P = .0498). In the survival analysis (n = 724; mean age 47.3), retention rates were 71.5% at 0.5 years but dropped to 47.9% at 2.0 years. Over 1.5 years, the Sustained Group showed a consistent body mass index (BMI) reduction from baseline (all P < .001) and stable Hemoglobin A1c National Glycohemoglobin Standardization Program (HbA1c) levels. Conversely, the Comparison Group showed increased BMI (P = .001) and HbA1c levels (P < .001) at 1.0 year. Medication use did not differ significantly between the groups. Regarding secondary lifestyle outcomes, the Sustained Group exhibited significantly higher physical activity (P < .001) and restorative sleep (P = .032), and lower frequencies of late-night dinners (P = .025), skipping breakfast (P = .006), daily alcohol consumption (P = .002), and smoking (P = .038).

Conclusions:

Behavioral changes in this population were delayed until the accumulation of multiple risks with age heightened the sense of crisis. The median duration was 2.0 years. This suggests that "controlled motivation", driven by health anxiety and institutional guidance, supports maintenance for approximately one year but is insufficient to overcome occupational structural barriers beyond two years. However, sustained behavioral changes yielded clear physiological improvements independent of pharmacotherapy. Future support strategies should shift from outcome-based to process-based evaluations to foster autonomous motivation and self-efficacy.