The psychosocial work environment and fatigue in Danish ferry shipping

Research output: Book/anthology/thesis/reportPh.D. thesisResearch

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Background
In general fatigue is a state in which the human organism is incapable of maintaining the original level of activity or mental processing due to prior physical, emotional or mental activity and/or absence of insufficient rest (1, 2). Work-related fatigue has been linked to ill health and endangerment of occupational safety, and in ferry shipping employees’ fatigue can lead not only to poor individual health and wellbeing but also to accidents, which can potentially jeopardize passengers’ safety.

Objective
Due to the risk of fatigue in the ferry shipping industry – and a lack of prior research on this topic - the main aim of this Phd study was to investigate the link between fatigue and working environmental factors among ferry shipping employees. The investigation specifically focuses on the role of psychosocial factors, as there is a distinct lack of research on such determinants in a seafaring context, and it has resulted in three papers, which have assessed the present empirical evidence on determinants of seafarers’ fatigue in a systematic review and examined the association between five domains of fatigue and physical- and psychosocial exposures with a cross-sectional survey among employees of two Danish ferry shipping companies.

Methods
A systematic review and quality assessment of the empirical evidence was conducted as an initial step to summarize and analyze what was known about fatigue-determining factors in seafaring, the results of which were published in article 1. Two further articles were based on a quantitative, cross-sectional observational study investigating the association between fatigue and the exposure to physical- and psychosocial working environmental factors. Data was collected with the help of a standardized self-report questionnaire among crew members and those working in the terminals of two Danish ferry ship companies from April to the end of September 2015. 513 employees were invited to the study (179 terminal workers and 334 crew members) and 193 returned a completed questionnaire yielding an overall response rate of 38 %. Fatigue was measured with the Swedish Occupational Fatigue Inventory (SOFI), a five-subscale instrument of which two subscales are considering psychological aspects of fatigue, another two physical aspects of the construct and the remaining one sleepiness. The Copenhagen Psychosocial Questionnaire (COPSOQ) was used for measuring four psychosocial domains of exposure, while single-item questions were used for measuring physical work stressors. The association of risk factors with fatigue was determined using hierarchical multiple linear regression analyses, testing for confounding, interaction and mediation.

Results
For the review, published in article 1, a total of 102 eligible studies were initially identified through systematic database searches. From reviewing the abstracts 83 articles were excluded, the main reason for exclusion being that fatigue not the outcome variable (article 1). Studies showed that poor sleep quality and being sleep-deprived have an adverse effect on fatigue. Additionally, night shifts and -watches are more fatiguing compared to day shifts and day- evening watches. Further, working in the 6h on-6h of watch system is associated with higher fatigue compared to the 4h on-8h of system, and fatigue was found to increase over watch/shift-time – a tendency that was also recognized for tour length. Surprisingly, only very few studies investigated the influence of the physical or the psychosocial working environment on fatigue, which made summarizing of evidence in this area seem premature.

Article 2 and 3 present the results of a cross-sectional study among Danish ferry ship employees. Main findings of article 2 were that job demands and job control were more important for fatigue than disturbance from the physical working environment, and effects tended to be stronger for psychological than for physical aspects of fatigue. In particular higher levels of demands were related to higher levels of fatigue on four of the five SOFI-subscales, i.e. lack of energy, physical exertion, lack of motivation and sleepiness, respectively, while a negative association was found between job control and the three psychological sub-dimensions of fatigue. Contrary to this, there was no support for a demand-control interaction. Furthermore, all effects of demand and control on fatigue were at least partly mediated by sleep satisfaction. Article 3 reports findings for the association between experience of work-family conflict, perceived supervisor support and the five subscales of SOFI. Higher levels of work-family conflict went along with higher levels in all aspects of fatigue except for physical exertion. Higher levels of supervisor support, on the other hand, were associated with lesser fatigue in three sub aspects of fatigue; lack of energy, physical exertion and lack of motivation.

Conclusion
The findings presented in this thesis suggest that besides the negative impact on seafarers’ fatigue from factors such as insufficient sleep, night work and working in 6h on-6h of watch system, which is well-established according to the scientific literature, the psychosocial work environment may play an important role, particularly for psychological fatigue. In particular job demands, and job control, which so far have been shown to be highly relevant in land-based occupations, were identified as potential determining factors for ferry ship employees’ fatigue. Further, beyond a general role of work demands, the more specific problem of work-family conflict as well as of supervisor support were identified as potentially important factors for fatigue experience. The results of this thesis suggest that work-site interventions which particularly aim at a good balance between work and family life, increase employee control and promote good leadership practices in the ferry ship industry may have potential as effective interventions against fatigue among its employees.
Translated title of the contributionDet psykosociale arbejdsmiljø og aftigue i Dansk færgefart
LanguageEnglish
PublisherSyddansk Universitet. Det Sundhedsvidenskabelige Fakultet
Number of pages70
Publication statusPublished - 2018

Note re. dissertation

Grad tildelt d. 25-01 2018