Work environment, neurophysiologic and psychophysiologic models among professional drivers with and without cardiovascular disease : Seeking an integrative neurocardiologic approach

Two work environment models, the self-reported job strain model (JSM) and the Occupational Stress Index (OSI), were applied among four groups of professional drivers (PD): 13 with ischaemic heart disease (IHD), 12 with hypertension (HTN), 10 with borderline hypertension (BHTN), 34 healthy PD and 23 non-PD referents. Neuro- and psychophysiologic models symbolically simulating aspects of the driving environment were applied; behavioural and standard risk factors were assessed. Among the PDs, there were significant correlations between job strain and the total OSI score, implying that both the ratio of demand/control and total OSI measure overall burden of the work environment upon this cohort. There was no significant between-groups effect for job strain. The total OSI scores differed significantly between groups, with significantly greater scores for each PD group compared to controls. The OSI includes a 'potential for disaster' dimension, implicated in cardiac risk, whose score among PDs was over twice that of controls. A logistic regression model was used to find which factors best distinguished normotensive PDs from the combined group of borderline plus hypertensive PDs. A greater body mass index, deadline pressure and amplitude of the event-related N2 component in response to an avoidance task and lower fear of driving score were significant independent indicators of HTN-BHTN status. Professional drivers with IHD had significantly smaller N2 amplitudes to the avoidance task, less activity recovery during the Glare Pressor Test and a greater fall in digital pulse amplitude with repeated glare exposure, compared to hypertensive PDs. Significant independent indicators of IHD as opposed to HTN status were longer work hours and more fear of driving. These findings indicate that the total burden of occupational stress is the backdrop for cardiovascular disease risk among these PDs, but a combination of neuro- and psychophysiologic and behavioural response patterns, together with exacerbating work stressors and standard risk factors, can contribute to this process. Further investigation in the direction of an integrated neurocardiologic approach is warranted.