Derrick Wong
The Association Between Baseline Health Conditions and Duration of Employment in Commercial Motor Vehicle Drivers
Mentor: Matthew Thiese, PHD, MSPH
Department: Occ. Environmental Health
Background/Purpose:
Commercial motor vehicle (CMV) drivers make up one of the largest categories of employment in the United States, with up to 9 million drivers. CMV drivers are an understudied and medically underserved population with poor access to healthcare services and education.
Goal: This research seeks to identify health conditions that may influence the duration drivers remain employed to inform health interventions and policy to improve driver retention and safety.
Methods:
Subjects: 74,381 CMV driver Federal Motor Carrier Safety Administration (FMCSA) medical exams were used with employment data from company records and federal databases.
Study Design: Retrospective cohort study
Variables: 13 baseline health conditions assessed in Commercial Driver Medical Exam certification (see Table 1)
Statistical Methods: Descriptive statistics, Wilcoxon Rank-Sum Tests, multivariate linear regressions, and Cox proportional hazards models were performed (adjusted for age and gender). All data was analyzed in SAS.
Results:
Average company tenure for CMV drivers was 0.8 years with 44.9% reporting having ≥ 1 baseline health condition.
Vision impairment and benzodiazepine use were associated with decreased company tenure.
Conversely, BMI > 35, OSA, hypertension, DM, cardiovascular disease, pulmonary disease, and seizures/epilepsy were all associated with increased company tenure even after adjusting for age and gender.
Conclusion:
Contrary to initial hypotheses, multiple baseline health variables were associated with greater tenure.
Survivorship bias may have contributed to these findings, in addition to not adjusting for crashes and prior driver experience.
Further research and analysis is needed to confirm the predictive validity of these variables.
