| 1. |
- Burström, Lage, et al.
(författare)
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A follow-up study of welders’ exposure to vibration in a heavy engineering production workshop
- 2010
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Ingår i: Journal of Low Frequency Noise Vibration and Active Control. - : Sage Publications. - 0263-0923 .- 1461-3484 .- 2048-4046. ; 29:1, s. 33-39
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Tidskriftsartikel (refereegranskat)abstract
- Manual work involving vibrating power tools is associated with symptoms that include vascular, neurological and musculoskeletal disorders. This study examines the vibration exposure of welders to determine the change between 1987 and 2008. Vibration measurements on handheld tools were used to evaluate the acceleration and the daily exposure time was determined by subjective rating. From these data, the 8-hour equivalent vibration exposure A(8), has been calculated. During the period, the A(8) decreased from 3.9 m/s2 to 1.9 m/s2. It was concluded that this decrease is the result of fewer vibrating tools and a decrease in daily exposure time. Although the daily vibration exposure has decreased over the study time, for some welders the daily vibration exposure A(8) is still above the action value set by the EU directive on vibration. This means more effort should be spent to decrease vibration exposure.
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| 2. |
- Liljelind, Ingrid, et al.
(författare)
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Determinants Explaining the Variability of Hand-Transmitted Vibration Emissions From Two Different Work Tasks : Grinding and Cutting Using Angle Grinders
- 2013
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press. - 0003-4878 .- 1475-3162. ; 57:8, s. 1065-1077
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Tidskriftsartikel (refereegranskat)abstract
- Background: There are numerous factors including physical, biomechanical, and individual that influence exposure to hand-transmitted vibration (HTV) and cause variability in the exposure measurements. Knowledge of exposure variability and determinants of exposure could be used to improve working conditions. We performed a quasi-experimental study, where operators performed routine work tasks in order to obtain estimates of the variance components and to evaluate the effect of determinants, such as machine–wheel combinations and individual operator characteristics.Methods: Two pre-defined simulated work tasks were performed by 11 operators: removal of a weld puddle of mild steel and cutting of a square steel pipe. In both tasks, four angle grinders were used, two running on compressed air and two electrically driven. Two brands of both grinding and cutting wheels were used. Each operator performed both tasks twice in a random order with each grinder and wheel and the time to complete each task was recorded. Vibration emission values were collected and the wheel wear was measured as loss of weight. Operators’ characteristics collected were as follows: age, body height and weight, length and volume of their hands, maximum hand grip force, and length of work experience with grinding machines (years). The tasks were also performed by one operator who used four machines of the same brand. Mixed and random effects models were used in the statistical evaluation.Results: The statistical evaluation was performed for grinding and cutting separately and we used a measure referring to the sum of the 1-s r.m.s. average frequency-weighted acceleration over time for completing the work task (a sa). Within each work task, there was a significant effect as a result of the determinants ‘the machine used’, ‘wheel wear’, and ‘time taken to complete the task’. For cutting, ‘the brand of wheel’ used also had a significant effect. More than 90% of the inherent variability in the data was explained by the determinants. The two electrically powered machines had a mean a sa that was 2.6 times higher than the two air-driven machines. For cutting, the effect of the brand of wheel on a sa was ~0.1 times. The a sa increased both with increasing wheel wear and with time taken to complete the work task. However, there were also a number of interaction effects which, to a minor extent, modified the a sa. Only a minor part (1%) of the total variability was attributed to the operator: for cutting, the volume of the hands, maximum grip force, and body weight were significant, while for grinding, it was the maximum grip force. There was no clear difference in a sa between the four copies of the same brand of each machine.Conclusions: By including determinants that were attributed to the brand of both machine and wheel used as well as the time taken to complete the work task, we were able to explain >90% of the variability. The dominating determinant was the brand of the machine. Little variability was found between operators, indicating that the overall effect as due to the operator was small.
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| 3. |
- Pettersson, Hans, et al.
(författare)
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Noise and hand-arm vibration exposure in relation to the risk of hearing loss
- 2012
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Ingår i: Noise & Health. - : Medknow. - 1463-1741 .- 1998-4030. ; 14:59, s. 159-165
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to examine the possible association of combined exposure of noise and hand-arm vibration (HAV) and the risk of noise-induced hearing loss. Workers in a heavy engineering industry were part of a dynamic cohort. Of these workers, 189 had HAV exposure, and their age and hearing status were recorded in the same year and were, therefore, included in the analysis. Data on HAV duration and acceleration was gathered through questionnaires, observations, and measurements. All available audiograms were categorized into normal and hearing loss. The first exposure variable included the lifetime HAV exposure. The lifetime HAV exposure was multiplied by the acceleration of HAV for the second and third exposure variable. Logistic regression using the Generalized Estimation Equations method was chosen to analyze the data to account for the repeated measurements. The analysis was performed with both continuous exposure variables and with exposure variables grouped into exposure quartiles with hearing loss as an outcome and age as a covariate. With continuous exposure variables, the odds ratio (OR) with a 95 confidence interval (CI) for hearing loss was equal to or greater than one for all exposure variables. When the exposure variables were grouped into quartiles, the OR with a 95 CI was greater than one at the third and fourth quartile. The results show that working with vibrating machines in an environment with noise exposure increases the risk of hearing loss, supporting an association between exposure to noise and HAV, and the noise-induced hearing loss.
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| 4. |
- Pettersson, Hans, et al.
(författare)
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Raynaud's phenomenon among men and women with noise-induced hearing loss in relation to vibration exposure
- 2014
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Ingår i: Noise & Health. - : Medknow. - 1463-1741 .- 1998-4030. ; 16:69, s. 89-94
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Tidskriftsartikel (refereegranskat)abstract
- Raynaud's phenomenon is characterized by constriction in blood supply to the fingers causing finger blanching, of white fingers (WF) and is triggered by cold. Earlier studies found that workers using vibrating hand-held tools and who had vibration-induced white fingers (VWF) had an increased risk for hearing loss compared with workers without VWF. This study examined the occurrence of Raynaud's phenomenon among men and women with noise-induced hearing loss in relation to vibration exposure. All 342 participants had a confirmed noise-induced hearing loss medico legally accepted as work-related by AFA Insurance. Each subject answered a questionnaire concerning their health status and the kinds of exposures they had at the time when their hearing loss was first discovered. The questionnaire covered types of exposures, discomforts in the hands or fingers, diseases and medications affecting the blood circulation, the use of alcohol and tobacco and for women, the use of hormones and whether they had been pregnant. The participation rate was 41% (n = 133) with 38% (n = 94) for men and 50% (n = 39) for women. 84 men and 36 women specified if they had Raynaud's phenomenon and also if they had used hand-held vibrating machines. Nearly 41% of them had used hand-held vibrating machines and 18% had used vibrating machines at least 2 h each workday. There were 23 men/6 women with Raynaud's phenomenon. 37% reported WF among those participants who were exposed to hand-arm vibration (HAV) and 15% among those not exposed to HAV. Among the participants with hearing loss with daily use of vibrating hand-held tools more than twice as many reports WF compared with participants that did not use vibrating hand-held tools. This could be interpreted as Raynaud's phenomenon could be associated with an increased risk for noise-induced hearing loss. However, the low participation rate limits the generalization of the results from this study.
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| 5. |
- Pettersson, Hans, et al.
(författare)
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Risk of Hearing Loss Among Workers with Vibration-Induced White Fingers
- 2014
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Ingår i: American Journal of Industrial Medicine. - : Wiley. - 0271-3586 .- 1097-0274. ; 57:12, s. 1311-1318
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundWe examined the risk of hearing loss for workers who use hand-held vibrating tools with vibration-induced white fingers (VWF) compared to workers without VWF. MethodsData on 184 participants from a 21-year cohort were gathered with questionnaires and measurements. The effects on hearing status of VWF, hand-arm vibration exposure, smoking habits, age and two-way interactions of these independent variables were examined with binary logistic regression. Analyses were made for the right hand and ear as well as for the hand with VWF and the ear with worse categorized hearing status. ResultsWorkers with VWF in their right hand had an increased risk of hearing loss (odds ratio 2.2-2.3) in the right ear. Workers with VWF in any hand did not have any increased risk of hearing loss in the ear with worse hearing status. ConclusionsThis study supports the hypothesis that VWF increases the risk of hearing loss among workers who use hand-held vibrating tools in a noisy environment. Am. J. Ind. Med. 57:1311-1318, 2014. (c) 2014 Wiley Periodicals, Inc.
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| 6. |
- Pettersson, Hans, 1980-
(författare)
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Risk of hearing loss from combined exposure to hand-arm vibrations and noise
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hearing loss from noise exposure is one of the most common occupational injuries, and exposure to vibrations may increase the risk of noise-induced hearing loss. Earlier cross-sectional and longitudinal studies found an increased risk of noise-induced hearing loss among workers with vibration-induced white fingers (VWF) symptoms compared to workers without such symptoms. It has been suggested that vibrations to the hand stimulate the sympathetic nervous system and cause vasoconstriction in both the exposed hand and the ears and that this contributes to noise-induced hearing loss. The overall aim of this thesis was to examine how hand-arm vibrations (HAV) interact with noise in the development of noise-induced hearing loss.The experimental study in this thesis examined the effects of HAV and noise, both separately and combined, on the temporary threshold shift (TTS) in hearing in 22 healthy male and female subjects. The two longitudinal studies in this thesis were based on a cohort of 189 male workers at a heavy engineering workshop. The first cohort study examined the risk of noise-induced hearing loss from long-term exposure to HAV and noise. The second cohort study examined if workers with VWF had an increased risk of noise-induced hearing loss compared to workers without such symptoms. Finally, the questionnaire study in this thesis examined the occurrence of Raynaud’s phenomenon among 133 men and women with noise-induced hearing loss in relation to exposure to vibrations.In the experimental study, no differences in TTS in hearing were observed after combined exposure to HAV and noise compared to exposure to only noise. In the first cohort study, there was an increased risk of noise-induced hearing loss with increased exposure to HAV in a noisy environment. In the second cohort study, it was found that workers with VWF had an increased risk of noise-induced hearing loss compared to workers without VWF. In the questionnaire study, many men and women with noise-induced hearing loss had used hand-held vibrating machines suggesting that vibrations might contribute to noise-induced hearing loss. A high prevalence of Raynaud’s phenomenon was found among men.This thesis demonstrated that there was a long-term effect on noise-induced hearing loss from combined exposure to noise and HAV, but no short-term effect, and that having Raynaud’s phenomenon may also increase the risk of noise-induced hearing loss.
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| 7. |
- Pettersson, Hans, et al.
(författare)
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The effect on the temporary threshold shift in hearing acuity from combined exposure to authentic noise and hand-arm vibration
- 2011
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Ingår i: International Archives of Occupational and Environmental Health. - New York : Springer. - 0340-0131 .- 1432-1246. ; 84:8, s. 951-957
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Tidskriftsartikel (refereegranskat)abstract
- This study examined and compared the effect on temporary threshold shift in hearing (TTS) in healthy subjects of noise and hand-arm vibration (HAV) combined and separately using controlled and authentic exposure conditions. This study also investigated the effect on TTS in hearing in relation to gender after such exposures.Twenty-two healthy subjects (11 men/women, mean age 22 years, range 18-31 years) were exposed both separately and in combination with HAV (6.7 m/s(2)), using vibrating handles and to noise (99dB(A)) using headphones, for 20 min. The HAV and noise were reproduced from recordings from angular grinder in operation. Hearing thresholds at 1, 4, and 8 kHz were measured before and up to 30 min after exposure. Combined exposure to noise and HAV created significantly greater TTS in hearing than HAV exposure at 4 and 8 kHz alone. After exposure to HAV, there was no significant change in hearing threshold. At 1 kHz, there was a significant difference between noise and HAV exposure in TTS in hearing. There was no significant difference between combined exposure and noise exposure for any test frequency. There was no significant difference in TTS in hearing in relation to gender for 1, 4, and 8 kHz for HAV, noise, or a combined exposure.The results indicate that there is no difference in the TTS in hearing after combined exposure compared to noise exposure alone. HAV exposure did not change the hearing threshold. The TTS in hearing did not differ significantly in relation to gender after HAV, noise, or combined exposure.
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| 8. |
- Pettersson, Lage, et al.
(författare)
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A structural study of D-mannitolatodimolybdate(VI) complexes in aqueous solution
- 2014
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Ingår i: Polyhedron. - : Elsevier. - 0277-5387 .- 1873-3719. ; 81, s. 308-311
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Tidskriftsartikel (refereegranskat)abstract
- Abstract The structure of the D-mannitolatodimolybdate(VI) complex has been determined by means of large angle X-ray scattering (LAXS) in aqueous solution at two pH values, 2.0 and 5.5. The two complexes have in principle the same structure in aqueous solution, two face-sharing molybdate(VI) octahedra connected to one D-mannitol ligand, as previously observed in the solid state. In the deprotonated form of the complex, pH 5.5, the D-mannitol ligand has lost a proton and as a result the Mo⋅⋅⋅Mo distance is 0.054 Å shorter than the protonated form, pH 2.0. This indicates that it is a proton on an oxygen shared by molybdate groups that leaves the complex at deprotonation and forces the molydate(VI) octahedra even closer to each other.
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