Symptoms of hand-arm vibration syndrome in gas distribution operatives

Exposure-response relation for vibration-induced white finger: inferences from a published meta-analysis of population groups

PURPOSE

It is questioned whether the exposure-response relation for the onset of vibration-induced white finger (VWF) in ISO 5349-1:2001 needs to be revised based on the epidemiologic studies identified by Nilsson et al. (PLoS One https://doi.org/10.1371/journal.pone.0180795 , 2017), and whether the relation they derive improves the prediction of VWF in vibration-exposed populations.

METHODS

A pooled analysis has been performed using epidemiologic studies that complied with selection rules and reported a VWF prevalence of 10% or more, and exposure constructed according to the provisions of ISO 5349-1:2001. The lifetime exposures at 10% prevalence were calculated for various data sets using linear interpolation. They were then compared to both the model from the standard and that developed by Nilsson et al. RESULTS: Regression analyses reveal excluding extrapolation to adjust group prevalences to 10% produce models with 95-percentile confidence intervals that include the ISO exposure-response relation but not that in Nilsson et al. (2017). Different curve fits are obtained for studies involving daily exposure to single or multiple power tools and machines. Studies with similar exposure magnitudes and lifetime exposure durations but markedly different prevalences are observed to cluster.

CONCLUSIONS

A range of exposures and A(8)-values is predicted within which the onset of VWF is most likely to occur. The exposure-response relation in ISO 5349-1:2001, but not that proposed by Nilsson et al., falls within this range and provides a conservative estimate for the development of VWF. In addition, the analyses suggest that the method for evaluating vibration exposure contained in ISO 5349-1:2001 needs revision.

Raynaud's phenomenon in the occupational context

OBJECTIVE

To review articles that evaluated the prevalence of Raynaud's phenomenon of occupational origin.

METHODS

The search for articles was carried out in the Medline (via PubMed), Embase, Web of Science, Scientific Electronic Library Online (SciELO), and Latin America and Caribbean Health Sciences Literature (Lilacs) databases.

RESULTS

64 articles were obtained from the electronic search; 18 articles met the eligibility criteria. All studies discussed the exposure to vibrations in the upper limbs. In 6 of them, the thermal issue was directly or indirectly addressed. No studies have addressed exposure to vinyl chloride.

CONCLUSIO

In general, a higher prevalence of Raynaud's phenomenon was found among vibratory tool operators compared to non-exposed workers, with an increase in the number of cases the higher the level of vibration and the time of exposure. Cold is a triggering and aggravating factor of the Raynaud phenomenon and seems to play an important role in the emergence of vascular manifestations of the hand-arm vibration syndrome.

Lifetime vibration dose correlates with severity of the neurological component of hand-arm vibration syndrome among tyre shop workers in Kelantan, Malaysia

Introduction. Cumulative lifetime exposure to vibration is believed to contribute to more severe complications of hand-arm vibration syndrome (HAVS). Objectives. To determine prevalence of the neurological component of HAVS and the correlation between lifetime vibration dose (LVD) and neurological severity of HAVS among tyre shop workers in Kelantan. Methods. The cross-sectional study involved 200 tyre shop workers from two districts in Kelantan. Part one data were collected in the field using a questionnaire and hand-arm vibration was measured. Part two involved a set of hand clinical examinations (Purdue pegboard, Semmes-Weinstein monofilament and two-point discrimination tests) carried out for neurological component severity staging. LVD for each worker was calculated from data gathered in part one. For workers who had neurological symptoms, staging according to Stockholm workshop scales was done according to part two data. The strength of correlation between LVD and neurological stages was then determined using Spearman correlation. Results. Prevalence of neurological component was 37%. Spearman correlation between LVD and the neurological stages showed a moderate positive correlation. Conclusion. Cumulative lifetime exposure to hand-transmitted vibration is likely to be related to neurological severity of HAVS and therefore must be considered when assessing workers' exposure to hand-arm vibration.

Hand-arm vibration and the risk of vascular and neurological diseases-A systematic review and meta-analysis

Background

Increased occurrence of Raynaud’s phenomenon, neurosensory injury and carpal tunnel syndrome has been reported for more than 100 years in association with work with vibrating machines. The current risk prediction modelling (ISO-5349) for “Raynaud’s phenomenon” is based on a few studies published 70 to 40 years ago. There are no corresponding risk prediction models for neurosensory injury or carpal tunnel syndrome, nor any systematic reviews comprising a statistical synthesis (meta-analysis) of the evidence.

Objectives

Our aim was to provide a systematic review of the literature on the association between Raynaud’s phenomenon, neurosensory injuries and carpal tunnel syndrome and hand-arm vibration (HAV) exposure. Moreover the aim was to estimate the magnitude of such an association using meta-analysis.

Methods

This systematic review covers the scientific literature up to January 2016. The databases used for the literature search were PubMed and Science Direct. We found a total of 4,335 abstracts, which were read and whose validity was assessed according to pre-established criteria. 294 articles were examined in their entirety to determine whether each article met the inclusion criteria. The possible risk of bias was assessed for each article. 52 articles finally met the pre-established criteria for inclusion in the systematic review.

Results

The results show that workers who are exposed to HAV have an increased risk of vascular and neurological diseases compared to non-vibration exposed groups. The crude estimate of the risk increase is approximately 4–5 fold. The estimated effect size (odds ratio) is 6.9 for the studies of Raynaud’s phenomenon when including only the studies judged to have a low risk of bias. The corresponding risk of neurosensory injury is 7.4 and the equivalent of carpal tunnel syndrome is 2.9.

Conclusion

At equal exposures, neurosensory injury occurs with a 3-time factor shorter latency than Raynaud’s phenomenon. Which is why preventive measures should address this vibration health hazard with greater attention.

Validity and inter-observer reliability of subjective hand-arm vibration assessments

Exposure to mechanical vibrations at work (e.g., due to handling powered tools) is a potential occupational risk as it may cause upper extremity complaints. However, reliable and valid assessment methods for vibration exposure at work are lacking. Measuring hand-arm vibration objectively is often difficult and expensive, while often used information provided by manufacturers lacks detail. Therefore, a subjective hand-arm vibration assessment method was tested on validity and inter-observer reliability. In an experimental protocol, sixteen tasks handling powered tools were executed by two workers. Hand-arm vibration was assessed subjectively by 16 observers according to the proposed subjective assessment method. As a gold standard reference, hand-arm vibration was measured objectively using a vibration measurement device. Weighted κ's were calculated to assess validity, intra-class-correlation coefficients (ICCs) were calculated to assess inter-observer reliability. Inter-observer reliability of the subjective assessments depicting the agreement among observers can be expressed by an ICC of 0.708 (0.511-0.873). The validity of the subjective assessments as compared to the gold-standard reference can be expressed by a weighted κ of 0.535 (0.285-0.785). Besides, the percentage of exact agreement of the subjective assessment compared to the objective measurement was relatively low (i.e., 52% of all tasks). This study shows that subjectively assessed hand-arm vibrations are fairly reliable among observers and moderately valid. This assessment method is a first attempt to use subjective risk assessments of hand-arm vibration. Although, this assessment method can benefit from some future improvement, it can be of use in future studies and in field-based ergonomic assessments.

Vibration from a riveting hammer causes severe nerve damage in the rat tail model

INTRODUCTION

Hand-arm vibration syndrome (HAVS) is an occupational neurodegenerative and vasospastic disorder in workers who use powered hand tools. Frequency weighting (ISO 5349) predicts little risk of injury for frequencies >500 HZ. Potentially damaging high frequencies abound in impact tool-generated shock waves.

METHODS

A rat tail impact vibration model was developed to deliver shock-wave vibration from a riveting hammer to simulate bucking bar exposure. Rat tails were vibrated continuously for 12 min. Tail flick withdrawal times were determined for noxious heat. Nerve trunks and skin were processed for light and electron microscopy.

RESULTS

Immediately after vibration, the tails were hyperalgesic and had disrupted myelinated axons, fragmented nerve endings, and mast-cell degranulation. By 4 days, the tails were hypoalgesic; nerve endings were lost in the skin.

CONCLUSIONS

Shock-wave vibration causes severe nerve damage. Frequency weighting seriously underestimates the risk of nerve injury with impact tools.

Dose-response relationship between exposure to hand-arm vibration and health effects among metalworkers

OBJECTIVES

The aim of this study was to explore the relationship of exposure to hand-arm vibration (HAV) and vascular, sensorineural and musculoskeletal symptoms and symptoms of carpal tunnel syndrome (CTS) in a population of Finnish metalworkers.

METHODS

A questionnaire on HAV exposure and symptoms was sent to 530 metalworkers. Those who reported finger blanching, numbness or tingling of the fingers or symptoms of CTS were invited to further examinations (n = 133). Their cumulative lifelong exposure to HAV, the level of current exposure and the history of use of tools causing impulse vibration were evaluated. The association of different symptoms with the HAV exposure was assessed with logistic regression analyses adjusted for age and smoking. The vibration perception thresholds (VPTs) were tested according to ISO 13091-1:2001.

RESULTS

The cumulative exposure index varied between 0 and 115,000 m(2) years d s(-4), the mean being 20,591 m(2) years d s(-4). The average of current daily vibration exposure was 1.6 m s(-2) and 39% of the participants had a history of exposure to impulse vibration. Of the respondents, 49% reported white fingers, 66% neurosensory symptoms, 56% symptoms of CTS and 75% musculoskeletal symptoms. The cumulative exposure index was associated with symptoms of white fingers [odds ratio (OR) 2.4-4.5], with symptoms of CTS (OR 4.6-6.1), with neurosensory symptoms (OR 5.7-17.3) and with musculoskeletal symptoms (OR 4.7-5.4). The risk of all these symptoms increased as the cumulative vibration dose increased. The history of exposure to impulse vibration had a significant effect on the occurrence of neurosensory symptoms (P = 0.024). The current exposure to HAV correlated significantly with all of the above-mentioned symptoms. The results of the VPT test were associated with the level of cumulative exposure to HAV.

CONCLUSIONS

There seems to be a dose-response relationship between the cumulative lifetime vibration dose of the HAV and finger blanching, sensorineural symptoms, symptoms of CTS and musculoskeletal symptoms of upper limbs and neck in the group of metalworkers of the study. The risk for neurosensory symptoms was the most significantly related to exposure to HAV and also to impulse vibration. Further studies are needed to confirm the present results also in other occupational groups taking into account the possible synergistic effect of workload as well.

The prevalence of sensorineural symptoms attributable to hand-transmitted vibration in Great Britain: a national postal survey

BACKGROUND

Exposure to hand-transmitted vibration (HTV) can cause sensorineural symptoms in the upper limb, but its impact has not previously been assessed in the general population.

METHODS

To investigate, we mailed a questionnaire about exposures to HTV, finger blanching and sensory symptoms (numbness or tingling) in the upper limbs to a population sample comprising 21,201 working-aged men and women selected at random from the age-sex registers of 34 British general practices, and a further 993 randomly selected from the pay records of the armed services. Associations were explored using multiple logistic regression models to adjust for confounding, with the resultant odds ratios converted into prevalence rate ratios (PRs).

RESULTS

Of 12,907 respondents, 2,607 (20.2%) reported sensory symptoms in the upper limb during the past week. Sensory symptoms were more prevalent in those with blanching, and were commonly associated with exposure to HTV, especially in men. In comparison with men who had never been exposed to HTV, the PR in men exposed both at work and in leisure was 2.2 (95% CI 1.9-2.4). Associations were found even in those who had never blanched.

CONCLUSIONS

Sensorineural symptoms in the upper limbs are common. HTV is an important risk factor for such complaints in the general population.

Validity of self reported occupational exposures to hand transmitted and whole body vibration

OBJECTIVES

To assess the accuracy with which workers report their exposure to occupational sources of hand transmitted (HTV) and whole body vibration (WBV).

METHODS

179 Workers from various jobs involving exposure to HTV or WBV completed a self administered questionnaire about sources of occupational exposure to vibration in the past week. They were then observed at work over 1 hour, after which they completed a second questionnaire concerning their exposures during this observation period. The feasibility of reported sources of exposure during the past week was examined by questioning managers and by inspection of tools and machines in the workplace. The accuracy of reported sources and durations of exposure in the 1 hour period were assessed relative to what had been observed.

RESULTS

The feasibility of exposure in the previous week was confirmed for 97% of subjects who reported exposure to HTV, and for 93% of subjects who reported exposure to WBV. The individual sources of exposure reported were generally plausible, but occupational use of cars was substantially overreported, possibly because of confusion with their use in travel to and from work. The accuracy of exposures reported during the observation period was generally high, but some sources of HTV were confused-for example, nailing and stapling guns reported as riveting hammers, and hammer drills not distinguished from other sorts of drill. Workers overestimated their duration of exposure to HTV by a median factor of 2.5 (interquartile range (IQR) 1.6-5.9), but estimated durations of exposure were more accurate when the exposure was relatively continuous rather than for intermittent short periods. Reported durations of exposure to WBV were generally accurate (median ratio of reported to observed time 1.1, IQR 1.0-1.2).

CONCLUSIONS

Sources of recent occupational exposure to vibration seem to be reported with reasonable accuracy, but durations of exposure to HTV are systematically overestimated, particularly when the exposure is intermittent and for short periods. This raises the possibility that dose-response relations may have been biased in some of the studies on which exposure standards might be based, and that the levels in currently proposed standards may be too high. Future studies should pay attention to this source of error during data collection.