Functional Decline and Work Ability in Professional Drivers: A Multidimensional Occupational Medicine Approach Integrating Lifestyle, Metabolic Risk and Biological Ageing

Background. Population ageing and longer working lives are major public health challenges. Professional drivers are exposed to sedentary work, irregular schedules, traffic-related pollution, psychosocial stress and sleep disruption, which may promote cardiometabolic risk, accelerated biological ageing and functional vulnerability. However, integrated biological, clinical, cognitive and occupational assessments in this population remain limited. Aim. Within the LAINBIO (Work and Biological Ageing) project, this study aimed to characterize functional status and its biological, clinical and occupational determinants in professional drivers. Specific objectives were to develop a composite Functional Decline Score (FDS), estimate biological age using the Klemera–Doubal Method (KDM) and PhenoAge, measure urinary oxidative stress biomarkers, and investigate their associations with functional decline, cardiovascular risk and multimorbidity. Materials and Methods. A cross-sectional study was conducted on 103 professional drivers undergoing mandatory fitness-to-drive examinations. Participants underwent clinical evaluation, psychomotor vigilance testing, ECG, audiometry, and completed validated questionnaires (WAI, MMSE, ESS and CCI). Blood and urine samples were collected for biological age estimation and oxidative stress biomarker analysis. The FDS was developed using Multiple Correspondence Analysis integrating MMSE, WAI, vigilance, ECG and audiometric findings. Associations were assessed using permutation-based multiple linear regression adjusted for age, sex, smoking and education. Cardiovascular risk was estimated with the Italian CUORE Risk Score. Results. Participants showed a high prevalence of excess body weight (71%), current smoking (30%), and cardiovascular/metabolic comorbidities. Most maintained normal cognitive function (91%) and good-to-excellent work ability (66%), whereas vigilance regularity was impaired more frequently than reaction speed, suggesting sustained attention as an early marker of functional vulnerability. The FDS showed good discriminative ability and acceptable bootstrap stability. Multimorbidity (CCI) was the strongest determinant of functional decline (corrected p = 0.030), while urinary 8-OHdG showed a borderline association (corrected p = 0.051). Only PhenoAge, but not KDM, was associated with cardiovascular risk (Spearman r = 0.229, p = 0.032) and multimorbidity (p = 0.039). Discussion and Conclusions. Professional drivers may experience early biological and functional vulnerability despite remaining clinically fit for work. The FDS provides a multidimensional assessment of functional status beyond conventional evaluation. Among the biological age measures, PhenoAge proved the most clinically informative, showing associations with multimorbidity and cardiovascular risk. These findings support integrating multidimensional functional assessment and biological age estimation into occupational health surveillance. Longitudinal studies are needed to validate this approach.