An integrative approach to neurocardiologic mechanisms of heart disease risk in professional drivers : Application of neuro-psycophysiologic and work enviornment models
Sammanfattning: Aim: This dissertation aims to apply, develop and integrate neurophysiologic,psychophysiologic, and work environment models, along with behavioral and biomedicalrisk factors" to provide insight into the neurocardiologic mechanisms of heartdisease risk in professional drivers (PD). Methods: Subjects were male PD, age 25-52: 13 with ischemic heart disease(IHD), 12 hypertensives (HTN), 10 borderline hypertensives (BHTN) and 34 normotensives(NTN), and 23 non-PD controls. Electroencephalographic (EEG) parameters in responseto 5 minutes rest and 3 minutes exposure to darkness were: alpha abundance, amplitudeand frequency. Alpha abundance in response to headlight glare was assessed and theconsequent emotion, finger pulse volume (FPV) and blood pressure responses were examined.Event related potentials (ERP) were assessed hy an odd ball paradigm, in which redand green signals reminiscent of traffic light were target and non-target respectively.Occupational stress was assessed using the Job Strain (JS) and Occupational StressIndex (OSI). Type A behavior (TAB) was assessed by means of observation and questionnaire.Other behavioral, occupational and biomedical risk factors were assessed by meansof questionnaire. Main results: After glare exposure the IHD drivers showed significantlymore marked blockade of alpha activity, rise in diastolic blood pressure (DBP), persistentfall in FPV and lower expressed mean negative emotion than the odher groups. TheBHTN group reacted initially to glare with DBP rise and FPV fall. Normotensive PD> age 40 maintained a constant DBP. Anxiety trait and long work hours were associatedwith heightened central arousal to glare in PD. The IHD drivers showed the smallestamplitude of the N2 component of ERP. The HTN drivers showed the largest N2 followedby the BHTN drivers. Diastolic BP reactivity to the ERP was highest among IHD drivers.Those drivers who recovered baseline levels of alpha activity to the glare exposure,showed a significantly larger N2, compared to those who did not. In response to laboratorydarkness exposure alpha abundance diminished significantly for darkness comparedto rest period for all groups. IHD drivers were the only group to show significantincrease in dominant alpha frequency at darkness. They also had the highest TAB questionnairescores and the heaviest exposure to professional driving. Type A scores were significantlycorrelated with dominant alpha frequency during darkness. Low availability of attachment(AVAT) (a means of social support in the general life situation) and special drivinghazards best predicted TAB scores in PD. There were significant between group differenceswith respect to Symbolic Aversiveness at the work place, comparing each driver groupwith the non-professional driver control group PD were distinguished from the controlgroup by a twice higher total OSI score. A greater body mass index, deadline pressure,amplitude of the N2 and lower fear during driving were independent indicators ofHTN-BHTN as opposed to NTN status in PD. Indicators of IHD status as opposed to HTNwere longer work hours and more expressed fear during driving. The total OSI andnumber of smoking years predicted current smoking intensity among PD. BMI was bestpredicted by professional hours at the wheel, the inverse of JS and of AVAT. Long,irregular work hours were identified as a major stressor by the PD. "Need toalways be watchful" was identified as the most difficult aspect of work by thePD with many years in the profession. Conclusion: Drivers with IHD showed more evidence of immediate denial butfrom some points of view also more "sensitization" in response to the laboratorystressors manifested by more prolonged reactions than other groups. HTN and BHTNdrivers showed different patterns suggesting reversible neuro-psychophysiologicalstrain in response to the laboratory stressors. Amount of exposure to professionaldriving and Type A behavior were components statistically significantly "explaining"the typical IHD reactions. The directions of causality are unknown in this type ofcross-sectional study. The findings, however, point to a possibility that longlastingexposure to long hours of daily professional driving may accelerate the developmentof a typical IHD reaction pattem that could be part of the cardiovascular etiology.This warrants further studies, preferably longitudinal ones that could elucidatethe development of each reaction pattern. Key words: professional drivers, ischemic heart disease, EEC, ERP, TypeA behavior, Stress, Job Strain, headlight glare, night driving Reza Emdad ISBN 91-628-2710-3 Stockholm AKADEMITRYCK AB 590 98 Edsbruk 1997
Denna avhandling är EVENTUELLT nedladdningsbar som PDF. Kolla denna länk för att se om den går att ladda ner.