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dc.contributor.authorIrgens-Hansen, Kajaen_US
dc.date.accessioned2016-04-15T11:08:03Z
dc.date.available2016-04-15T11:08:03Z
dc.date.issued2016-05-06
dc.identifier.isbn978-82-308-3350-6en_US
dc.identifier.urihttps://hdl.handle.net/1956/11917
dc.description.abstractBackground. Due to concerns regarding safety and health in the work environment of the Royal Norwegian Navy (RNoN), a questionnaire-based survey was conducted (2002 – 2003) to assess work-related risk factors and health problems among Navy personnel. Results from this questionnaire study showed noise exposure as an important risk factor, and impaired hearing as an important health problem among Navy personnel. Also foreign navy studies point at noise exposure as a prevalent risk factor and hearing loss as a common health complaint among navy personnel. However, the literature concerning noise exposure and hearing loss in the navy is sparse and the issue has not been systematically investigated. The RNoN has experienced several accidents at sea. These accidents have been found to be associated with cognitive requirements regarding navigational task performance. Prior literature has indicated deleterious effects of noise exposure on cognitive performance. Thus, an association between RNoN navigation accidents and impaired cognitive performance due to noise exposure has been questioned. However, research on noise exposure and cognitive performance in naval and maritime settings is limited and shows contradicting results. Objectives. The main objective of this thesis was to gain more knowledge regarding the effects of noise exposure among navy personnel. The specific objectives of paper I were to assess the prevalence of hearing loss among Navy personnel and to examine the association between work on board vessels in the RNoN and hearing loss among Navy personnel. In paper II we aimed at investigating the incidence of significant threshold shift (STS) among Navy personnel between 2012 and 2014 and to identify determinants of STS among Navy personnel. The objective of paper III was to assess cognitive performance subsequent to noise exposure among Navy personnel on board RNoN vessels. Material and methods. 938 officers, enlisted and civilian Navy personnel from 48 vessels were invited to participate in a study on the relationship between noise and hearing loss. The study was conducted between 2012 and 2014 and comprised two examinations per person, i.e. at baseline and follow-up. Two separate questionnaires on noise exposure and health were prepared, one for each examination. Hearing was assessed by pure tone audiometry. At baseline, hearing loss was defined as hearing thresholds ≥ 25 dB in either ear at 3000, 4000 or 6000 Hz. At follow up, impaired hearing was defined as a STS, i.e. an average change in hearing thresholds between the two examinations ≥ + 10 dB at 2000, 3000 and 4000 Hz in either ear. Two to five Navy personnel on board 24 RNoN vessels were selected to participate in a study on the effects of noise exposure on cognitive performance. Noise exposure was assessed by personal noise dosimeter measurements, while cognitive performance was evaluated by using a visual attention test in which response time (RT) was measured. In order to assess possible confounding factors, the participants completed a log book. Results. The prevalence of hearing loss among Navy personnel at baseline was 31.4 %. Work on board RNoN vessels was significantly associated with reduced hearing after adjusting for age, gender and otitis as an adult. The incidence of STS from baseline to follow-up was 23.0 %. The noise exposure determinants ‘current exposure to loud noise > 15 hours/week during work on board’ and ‘number of gun shots during the last year’ were significantly associated with a higher risk of STS. A significantly increased RT was found among participants with the highest noise exposure (>85.2 dB(A)) and the next highest noise exposure (77.1 – 85.2 dB(A)) compared to participants with the lowest exposure (< 72.6 dB(A)). Conclusions. The prevalence of hearing loss and incidence of STS among Navy personnel was 31.4 % and 23.0 %, respectively. In the cross-sectional study, an association between work on board RNoN vessels and hearing loss was found. In the longitudinal study, we found a significant association between STS and current exposure to loud noise > 15 hours/week on board RNoN vessels. We also found a significant association between STS and number of gun shots during the last year. The Navy personnel with the highest noise exposure performed poorer on a cognitive performance test than personnel with the lowest noise exposure. It is likely that noise exposure on RNoN vessels causes hearing loss and affects cognitive performance among the Navy personnel on board.en_US
dc.language.isoengeng
dc.publisherThe University of Bergeneng
dc.relation.haspartPaper I: Irgens-Hansen, K., Sunde E., Bråtveit M., Baste V., Oftedal G., Koefoed V.F., Lind O., Moen B.E. (2015): “Hearing loss in the Royal Norwegian Navy: a cross-sectional study”, International Archives of Occupational and Environmental Health, 88(5), 641 – 649. The article is available in BORA at: <a href="http://hdl.handle.net/1956/9602" target="blank">http://hdl.handle.net/1956/9602</a>en_US
dc.relation.haspartPaper II: Irgens-Hansen, K., Baste V., Bråtveit M., Lind O., Koefoed V.F., Moen B.E. (2015): “Hearing loss in the Royal Norwegian Navy: a longitudinal study” (Submitted). This article is not available in BORA.en_US
dc.relation.haspartPaper III: Irgens-Hansen, K., Gundersen, H., Sunde E., Baste V., Harris A., Bråtveit M., Moen B.E. (2015): “Noise exposure and cognitive performance: A study on personnel on board Royal Norwegian Navy vessels”, Noise & Health, 17 (78), 320 – 327. This article is not available in BORA. The published version is available at: <a href="http://dx.doi.org/ 10.4103/1463-1741.165057" target="blank"> 10.4103/1463-1741.165057</a>en_US
dc.titleEffects of noise exposure among navy personnel. Hearing loss and cognitive performanceen_US
dc.typeDoctoral thesis
dc.rights.holderCopyright the author. All rights reserved.


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