Hand-arm vibration syndrome and dose-response relation for vibration induced white finger among quarry drillers and stonecarvers. Italian Study Group on Physical Hazards in the Stone Industry

Risk of Raynaud's Phenomenon Among Workers in the Occupational Disease Surveillance System

INTRODUCTION

Raynaud's phenomenon (RP) is linked to occupational exposures such as vibration, cold temperature, and chemicals. However, large cohort studies examining RP by occupation and sex are scarce. To address this gap, this study aimed to assess risk of RP by both occupation and sex in a large cohort of workers in Ontario, Canada.

METHODS

Workers with accepted lost-time compensation claims were linked to physician billing records to identify diagnoses of RP between 2002 and 2020. A 3-year washout (disease-free) period was applied, and follow-up was limited to 5 years. Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for diagnoses of RP, adjusted for age at start of follow-up, birth year, and stratified by sex.

RESULTS

A total of 7,131 RP cases were identified among 810,739 workers. Among men, higher risks were observed for truck drivers (HR = 1.23, 95% CI = 1.08-1.41), driver-salesmen (HR = 2.54, 95% CI = 1.21-5.34), those in mining and quarrying-related cutting, handling, and loading (HR = 2.57, 95% CI = 1.29-5.15), and construction trades laboring and elemental work (HR = 1.70, 95% CI = 1.24-2.34). Among women, higher risks were observed for those working in waitressing and related (HR = 1.70, 95% CI = 1.22-2.38), food and beverage preparation (HR = 1.34, 95% CI = 1.02-1.76), and electrical equipment fabricating and assembling (HR 1.96, 95% CI = 1.08-3.55).

CONCLUSION

Study findings show elevated risks of RP among various occupations, with notable differences between men and women. These differences may be attributable to variations in potential exposures and susceptibility to RP. Findings underscore the need for large cohort studies to examine RP across various occupational groups and both sexes.

Quantitative Assessment of Work-related Hand-arm Vibration Exposure Among Workers in the Construction, Underground Coal Mining, Wood Working, and Metal Working Industry: The German Hand-arm Vibration Study

Background

Standardized exposure assessments were conducted to quantify the historical occupational exposure to hand-arm vibration of workers in the German construction, underground coal mining, woodworking, and metalworking industries.

Methods

A two-step approach was used to assess historical vibration exposure. In the first step, individual work histories were reconstructed by standardized personal interviews. The interview focused on the identification of relevant power tools used throughout the working life. In the second step, an equipment-exposure-matrix was constructed by industrial hygiene measurements. By linking the power tools in the work history to the equipment-exposure-matrix, individual daily, and long-term vibration exposures can be quantified.

Results and conclusions

A total of 423 power tools were identified for 5,115 exposure segments over a period of 50 years. 97.2% of the vibration values were based on industrial hygiene measurements. The total vibration value (ahv) of the power tools used varied between 0.8 m/s2 and 65.2 m/s2 with a median value of 14.2 m/s2. The median value of cumulative vibration exposure is Dhv = 121,971 (range: 23-3,374,640) m2/s4·day, corresponding to a daily vibration exposure of ahv(8) = 7 m/s2 for 2489 working days (11.3 years).This study provides a detailed description of hand-arm vibration exposure among workers in the related industries studied. Our analyses indicate that the quantification of daily vibration exposure is often uncertain and should be interpreted with caution. In contrast, cumulative vibration exposure is a more reliable exposure parameter for describing general working conditions and for guiding the prevention and compensation of vibration-related health problems.

Dupuytren's disease and occupational mechanical exposures: a systematic review and meta-analysis

The risk of developing Dupuytren's disease among workers exposed to occupational mechanical exposures has been reported in few systematic reviews, mainly related to vibration. Expanding the investigation to all occupational mechanical exposures is essential for advancing scientific knowledge, health policies and improving workplace safety. The aim of this systematic review and meta-analysis was to study the association between occupational mechanical exposures and Dupuytren's disease.We conducted a systematic review and meta-analysis using guidelines stated by PRISMA. The systematic literature search was performed in Medline, EMBASE, CINAHL, Cochrane Library and Web of Science databases in April 2023. Inclusion criteria were conducted using the PECOS. Two independent authors conducted the literature screening, data extraction and risk of bias assessment. In the meta-analyses, data was pooled using random-effects models and stratified by the risk of bias and study design. The level of evidence was evaluated using GRADE.The literature search identified 563 unique articles and 15 were deemed eligible for inclusion, categorised into hand-transmitted vibration, lifting/carrying loads and combined mechanical exposures. Exposure to hand-transmitted vibration showed an OR of 2.0 (95% CI 1.5 to 2.7, I2=64%), lifting/carrying loads had an OR of 1.5 (95% CI 1.1 to 2.0, I2=77%) and combined mechanical exposures had an OR of 2.1 (95% CI 1.4 to 3.1, I2=94%). When grading the level of evidence, we found moderate evidence for hand-transmitted vibration, while low evidence was found for lifting/carrying loads and combined mechanical exposures.We found an association between hand-transmitted vibration, lifting/carrying loads and combined mechanical exposures. The level of evidence was considered moderate for hand-transmitted vibration and low for lifting/carrying loads and combined mechanical exposures.

Understanding Environmental Consequences of Quarry Operations: Residents' Perception Study in the Neighbourhood of a Quarry in Osun state, Nigeria

Investigation on human perspective on the impacts of quarry activities on the natural environment remains limited. This study gauged residents' perceptions of the ecological consequences of quarry operations. A meticulously structured questionnaire was dispensed among 214 households, chosen at random, in the vicinity of Sanlong Quarry within Obaagun community, Ifelodun Local Government Area, Osun State, Nigeria. The dataset underwent analysis utilising both descriptive and inferential statistics. Results indicated a predominance of female respondents, constituting 77.6%, with 65% aged 41 years and above. Moreover, 74.2% had been residents in the study area for no less than 7 years, and 62.6% resided within 1 km of the quarry site. A substantial 74.3% (159 residents) regarded quarry operations as detrimental to their environment, with 72.2% attributing this to machine vibrations. Kaiser-Meyer-Olkins and Barttlet's tests affirmed the factorability of the dataset at a 77.5% significance level (P < .005). Factor analysis revealed 7 variables, encompassing 79.19% of residents' perceptions of the environmental impact of quarry operations. These variables included the loss of farmlands (21.35%), degraded farmland (15.06%), vibrations from heavy machines affecting buildings (10.64%), flyrock debris from rock blasting damaging roofs, and the destruction caused by trucks and heavy machinery on rural roads (8.57%). Additionally, wildlife displacement (8.33%) and respondents' perception of the quarry's duration of operation (8.00%) were identified. These findings suggest that quarry operations exert a significant influence on the livelihood of the Sanlong quarry neighbourhood. It is imperative for stakeholders to address this situation through relevant policies, particularly those that enhance the well-being of the community and hold the quarry company responsible for the damages inflicted on various environmental resources. Nonetheless, further study is recommended to validate or otherwise the current findings.

Exposure to hand-arm vibrations in the workplace and the occurrence of hand-arm vibration syndrome, Dupuytren's contracture, and hypothenar hammer syndrome: a systematic review and meta-analysis

This study provides an overview of the relationships between exposure to work-related hand-arm vibration and the occurrence of pre-defined disorders of the hands. We searched Medline, Embase, Web of Science, Cochrane Central, and PsycINFO for cross-sectional and longitudinal studies on the association between work-related vibration exposure and the occurrence of hand-arm vibration syndrome (including vibration-induced white finger), Dupuytren's contracture, or hypothenar hammer syndrome. We used a 16-item checklist for assessing the risk of bias. We present results narratively, and we conducted random effects meta-analyses if possible. We included 10 studies with more than 24,381 participants. Our results showed statistically significant associations between the exposure to hand-arm vibrations and the occurrence of the selected disorders, with pooled odds ratios ranging between 1.35 (95% CI: 1.28 to 2.80) and 3.43 (95% CI: 2.10 to 5.59). Considerable between-study heterogeneity was observed. Our analyses show that exposure to vibrating tools at work is associated with an increased risk for the occurrence of selected disorders of the hands. Due to the majority of studies being cross-sectional, no firm conclusion is possible regarding causal relationships between vibration exposure and disorder occurrence. Future research should specifically address whether reducing exposure to hand-held vibrating tools at work reduces the incidence of the disorders of the hands investigated in this systematic review.

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.

An Investigation of the Effects of Drill Operator Posture on Vibration Exposure and Temporary Threshold Shift of Vibrotactile Perception Threshold

The present study involved performing an experiment to clarify whether vibration measurement values on the tool handle, in accordance with ISO 5349-1, can assess risk from workplace environments. The study investigated the relationship between the vibration magnitude of a hand-held electric drill with different operating postures. The experiment included the determination of the participant’s temporary threshold shift (TTS) of vibrotactile perception threshold (VPT) at the tip of the index finger. The experimental hypothesis was that the vibration measurement values on the tool handle, in accordance with the ISO 5349-1 standard, include the effect of posture on the vibration measurements obtained despite the variation in posture and test participants. The hand-transmitted vibration (HTV) was applied using a hand-held electric drill applied to a pre-cast concrete paving slab substrate (600 × 600 × 50 mm, 55 MPa) using a 10 mm diameter masonry drill bit (without hammer action). The tool was operated using the right hand on twelve male subjects with three working postures (n = 36). Vibration was measured in three orthogonal directions according to the international standard ISO 5349-1 procedure. Vibration magnitudes were expressed as root-mean-square (r.m.s.) acceleration, frequency-weighted using the Wh frequency weighting. Clause 4.3 states that the characterisation of the vibration exposure is assessed from the acceleration of the surface in contact with the hand as the primary quantity. The experimental results indicate that the TTS following vibration exposure is not related to the measured vibration magnitude on the tool handle. Therefore, the automatic inclusion of posture and test participant variation is not proven. The results suggest that the vibration measurement values on the tool handle do not predict the TTS after hand-transmitted vibration in varying posture across the test participants. The research concludes that tool handle vibration measurement, in accordance with ISO 5349-1, does not properly assess the potential hazard from authentic workplace tool usage conditions of varying postures.

Adverse health manifestations in the hands of vibration exposed carpenters - a cross sectional study

BACKGROUND

Despite EU regulatory standards, many workers suffer injury as a result of working with hand-held vibrating tools. Our aim of this study was to confirm whether carpenters, a highly exposed group, suffer more injuries to their hands than painters, a group assumed to be less exposed to vibration.

METHODS

193 carpenters (participation rate 100%) and 72 painters (participation rate 67%), all men, answered a questionnaire and underwent a clinical examination to identify manifestations of neural and vascular origin in the hands. Neurosensory affection was defined as having at least one symptom in the fingers/hands (impaired perception of touch, warmth, or cold, impaired dexterity, increased sensation of cold, numbness or tingling, or pain in the fingers/hands when cold) and at least one clinical finding (impaired perception of touch, warmth, cold, vibration, or two-point discrimination). Logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Neurosensory affection was fulfilled for 31% of the carpenters and 17% of the painters, age-adjusted OR 3.3 (CI 1.6-7.0). Among carpenters with neurosensory affection 18% reported interference with daily life activities, the most common symptoms being increased sensation of cold, numbness and pain in the fingers/hands when cold, the most common clinical findings were impaired perception of touch and vibration. Neurosensory affection was found in 12% of young carpenters (≤ 30 years old). No difference was found in the prevalence of white fingers between carpenters and painters.

CONCLUSIONS

Carpenters showed more symptoms and clinical findings of neurosensory affection than painters, probably due to vibration exposure. Also young carpenters showed signs of neurosensory affection, which indicates that under current conditions workers at these companies are not protected against injury. This underlines the importance of reducing exposure to vibration and conducting regular medical check-ups to detect early signs of neural and vascular manifestations indicating hand-arm vibration injuries. Special attention should be given to symptoms of increased sensation of cold, pain in the fingers when cold, and numbness, as these were the most common initiating ones, and should be addressed as early as possible in the preventive sentinel process. It is also important to test clinically for small- and large-fibre neuropathy, as the individual may be unaware of any pathology.

Analysis of factors influencing the productivity of hammer drilling - user forces, human fatigue, drilling direction, and drill bit

In order to be able to develop a hammer drill with which the user can work as ergonomically and productively as possible, the relevant influencing factors must be known. In addition to the unknown influence of the drilling direction, there is a lack of understanding of the relations between user forces, human fatigue, and productivity. To analyze these relations, an experiment was carried out with 15 professional users. First, the influence of feed force, drilling direction, and drill bit on the rate of penetration was examined. Taking into account the rate of penetration and human fatigue, it was then investigated which of the three feed forces produces the highest productivity. Furthermore, the lateral forces applied by the participants during the drilling process were analyzed. Based on the study, it was found that the drilling direction (p < .001, r = -0.198) and the drill bit type (p < .041, r = -0.16) have a significant influence on the rate of penetration. Moreover, it was found that the rate of penetration tends to increase with higher feed forces, however, the theoretical cumulative drilling meters decrease when taking user fatigue into account. Finally, the experiment showed that the participating professionals applied lateral forces (Mdn = 16.7 N) of 13% to the feed force when working with a hammer drill. On the basis of this knowledge, investigations can be done to analyze the influences of lateral forces on the drilling process. The findings help drill and hammer drill manufacturers in testing and development processes. For craftsmen, on the other hand, the knowledge helps to perform the task as ergonomically and time-efficiently as possible.

Vibration related symptoms and signs in quarry and foundry workers

Purpose

The development of vascular and neurosensory findings were studied in two groups of long-term exposed quarry and foundry workers with different vibration exposures, working conditions and work tasks.

Methods

The study included 10 quarry workers (mean age 43 yrs., mean exposure time 16 yrs.) and 15 foundry workers (35 yrs.; 11 yrs.) at two plants in Sweden. All participants completed a basic questionnaire and passed a medical examination including a number of neurosensory tests, e.g. the determination of vibration (VPT) and temperature (TPT) perception thresholds as well as a musculoskeletal examination of the neck, shoulders, arms and hands.

Results

A high prevalence of neurosensory findings (40%) was found among the quarry workers. Both groups, however, showed a low prevalence of vibration white fingers (VWF). Foundry workers showed significantly better sensitivity than quarry workers for all monofilament tests (p ≤ 0.016), TPT warmth in dig 2 (p = 0.048) and 5 dexter (p = 0.008), and in dig 5 sinister (p = 0.005). They also showed a better VPT performance in dig 5 dexter (p = 0.031).

Conclusions

Despite high vibration exposure, the prevalence of VWF was low. The high prevalence of neurosensory findings among the quarry workers may depend on higher A(8) vibration exposure and higher exposure to high-frequency vibrations. An age-effect and exposure to cold could also be contributing factors. The nervous system seems to be more susceptible to high-frequency vibrations than the vascular system. For neurosensory injuries, the current ISO 5349-1 standard is not applicable.

Is Dupuytren's disease an occupational illness?

BACKGROUND

There is growing evidence for the risk of Dupuytren's disease (DD) from occupational exposure. For workers exposed to hand-transmitted vibrations (HTVs) and heavy manual work (HMW) who develop the disease, the inclusion of DD in hand-arm vibration syndrome and diseases of skeletal muscle overload could be beneficial for compensation purposes.

AIMS

To assess the risk of DD in workers exposed to HTVs and HMW, and to evaluate the length of exposure times that may significantly affect the development of DD.

METHODS

This study included male workers in Košice, Slovak Republic. Participants were divided into three groups: those exposed to HTVs, those exposed to HMW and controls. We evaluated the association between DD and HTVs, HMW, cardiovascular diseases, metabolic diseases, epilepsy, smoking and alcohol consumption for all groups. We also compared the length of exposure time to HTV and HMW between workers with and without DD.

RESULTS

The sample was comprised of 515 men, with 13% suffering from DD. Significant associations were found between DD and HTVs (OR 4.59 [95% CI 2.05-10.32]) and HMV (OR 3.10 [95% CI 1.21-7.91]). Highly significant associations were found between DD and older ages and alcohol consumption as well. No associations were found for the other variables. Exposure times greater than 15 years significantly increased the risk for DD (P < 0.01).

CONCLUSIONS

This study confirms a significant association between DD and both HTVs and HMW after long exposures. We suggest that DD should be considered as an occupational disease.

Musculoskeletal complications of hand-arm vibration syndrome among tyre shop workers in Kelantan, Malaysia

Objectives. Exposure to hand-arm vibration (HAV) is associated with hand-arm vascular syndrome (HAVS), which is characterized by musculoskeletal complications. However, evidence on this matter has been inconclusive. Therefore, this study aimed to determine and compare the prevalence of musculoskeletal complications of HAVS between a high-exposure (≥5 m·s^-2) group and a low-moderate-exposure (<5 m·s^-2) group and to explore the factors associated with the musculoskeletal complications of HAVS among tyre shop workers in Kelantan, Malaysia. Methods. A cross-sectional study involving 200 tyre shop workers was carried out. HAV was measured by a vibration meter. The workers were divided into two exposure groups - according to their 8-h time-weighted average, A(8), of vibration exposure - and compared. Results. Almost half of the workers reported musculoskeletal complications of the upper limbs and neck. Only the lifetime vibration dose (LVD) was significantly associated with the development of musculoskeletal complications. Conclusion. The high-exposure group had a higher prevalence of musculoskeletal complications. Only the LVD was significantly associated with complications. However, all factors of the work system, such as ergonomics, handgrip force and posture, might contribute to the development of musculoskeletal complications of HAVS and should be included in assessments.

Riveting hammer vibration damages mechanosensory nerve endings

Hand-arm vibration syndrome (HAVS) is an irreversible neurodegenerative, vasospastic, and musculoskeletal occupational disease of workers who use powered hand tools. The etiology is poorly understood. Neurological symptoms include numbness, tingling, and pain. This study examines impact hammer vibration-induced injury and recoverability of hair mechanosensory innervation. Rat tails were vibrated 12 min/d for 5 weeks followed by 5 week recovery with synchronous non-vibrated controls. Nerve fibers were PGP9.5 immunostained. Lanceolate complex innervation was compared quantitatively in vibrated vs sham. Vibration peak acceleration magnitudes were characterized by frequency power spectral analysis. Average magnitude (2515 m/s² , root mean squared) in kHz frequencies was 109 times that (23 m/s² ) in low Hz. Percentage of hairs innervated by lanceolate complexes was 69.1% in 5-week sham and 53.4% in 5-week vibration generating a denervation difference of 15.7% higher in vibration. Hair innervation was 76.9% in 5-weeks recovery sham and 62.0% in 5-week recovery vibration producing a denervation difference 14.9% higher in recovery vibration. Lanceolate number per complex (18.4 ± 0.2) after vibration remained near sham (19.3 ± 0.3), but 44.9% of lanceolate complexes were abnormal in 5 weeks vibrated compared to 18.8% in sham. The largest vibration energies are peak kHz accelerations (approximately 100 000 m/s² ) from shock waves. The existing ISO 5349-1 standard excludes kHz vibrations, seriously underestimating vibration injury risk. The present study validates the rat tail, impact hammer vibration as a model for investigating irreversible nerve damage. Persistence of higher denervation difference after 5-week recovery suggests repeated vibration injury destroys the capability of lanceolate nerve endings to regenerate.

Dupuytren's Disease and exposure to vibration: Systematic review and Meta-analysis

INTRODUCTION

Dupuytren's Disease (DD) occurs frequently in the entire population. Several risk factors are well known, including diabetes, alcohol, and age. In this meta-analysis, we assessed the role of occupational vibration exposure in the risk of DD, an issue currently under debate.

METHODS

We searched PubMed, Google Scholar, and the Cochrane Library to find references up to June 2019. DD prevalence was calculated using meta-proportion analysis. Differences in characteristics between DD patients and controls were expressed as standardized mean differences using the inverse of variance method or percentages using also meta-proportion analysis. We performed meta-regression analyses to assess the effects of alcohol, smoking, age, and sex on the DD incidence for the patients with DD that were exposed to vibrations.

RESULTS

We included 9 studies, comprising a total of 60,570 patients, including 1,804 DD patients. Prevalence of DD was 9.8% (95%CI: 5.9-14.4%). Compared with controls, patients with DD were older, more diabetic, more smokers and with a higher consumption of alcohol. Meta-analysis of the nine longitudinal studies comparing DD occurrence between patients exposed to vibration (626 of 6825) or not (1220 of 52,502) revealed a significantly increased DD incidence among patients with vibration exposure compared with controls (OR=2.87; 95%CI: 1.41-5.84). In metaregression we found no significant influence of all parameters on DD.

CONCLUSION

Age and environmental factors had no effect on DD prevalence among patients exposed to vibrations, despite a 10% prevalence in this group. Using vibration tools at work should be recognized as an important risk factor of developing DD.

Frequency-dependent changes in mitochondrial number and generation of reactive oxygen species in a rat model of vibration-induced injury

Regular use of vibrating hand tools results in cold-induced vasoconstriction, finger blanching, and a reduction in tactile sensitivity and manual dexterity. Depending upon the length and frequency, vibration induces regeneration, or dysfunction and apoptosis, inflammation and an increase in reactive oxygen species (ROS) levels. These changes may be associated with mitochondria, this study examined the effects of vibration on total and functional mitochondria number. Male rats were exposed to restraint or tail vibration at 62.5, 125, or 250 Hz. The frequency-dependent effects of vibration on mitochondrial number and generation of oxidative stress were examined. After 10 days of exposure at 125 Hz, ventral tail arteries (VTA) were constricted and there was an increase in mitochondrial number and intensity of ROS staining. In the skin, the influence of vibration on arterioles displayed a similar but insignificant response in VTA. There was also a reduction in the number of small nerves with exposure to vibration at 250 Hz, and a reduction in mitochondrial number in nerves in restrained and all vibrated conditions. There was a significant rise in the size of the sensory receptors with vibration at 125 Hz, and an elevation in ROS levels. Based upon these results, mitochondria number and activity are affected by vibration, especially at frequencies at or near resonance. The influence of vibration on the vascular system may either be adaptive or maladaptive. However, the effects on cutaneous nerves might be a precursor to loss of innervation and sensory function noted in workers exposed to vibration.

Dose-response relationship between hand-arm vibration exposure and vibrotactile thresholds among roadworkers

BACKGROUND

Testing of vibration perception threshold (VPT) at the fingertips as a quantitative measure of tactile sensitivity is a commonly used tool in diagnosing hand-arm vibration syndrome. There is limited research on dose-response relationships between hand-arm vibration (HAV) exposure and VPT on an individual level.

AIMS

Assess possible dose-response relationships on an individual level between HAV exposure and VPT at the fingertips.

METHODS

We assessed average daily vibration exposure (m/s²A8) and cumulative lifetime HAV exposure for 104 participants from different departments in a road maintenance company based on vibration measurements and questionnaires. VPT was measured based on the technical method described in ISO 13091-1:2005 using octave frequencies 8-500 Hz. We investigated associations using linear regression models with significance level p≤0.05.

RESULTS

The participants were either exposed to rock drills (n=33), impact wrenches (n=52) or none of these tools (n=19). Exposure to rock drills and impact wrenches was associated with elevated VPT for all seven test frequencies in the second and fifth fingers of both hands. A dose-response with the daily exposure measure m/s²(A8) was found based on 1.2 m/s²(A8) for impact wrenches, and 5.4 m/s²(A8) for rock drills. A stronger association was found with the cumulative exposure for rock drills compared with impact wrenches, and for the second finger compared with the fifth finger.

CONCLUSIONS

HAV exposure was associated with elevated VPT, also at exposure levels below the common exposure action value of 2.5 m/s²(A8). Lowering the HAV exposure can contribute to prevent increasing VPTs in these workers.

Ethnic differences in prevalence of Dupuytren disease can partly be explained by known genetic risk variants

Dupuytren disease (DD), a fibroproliferative disorder of the palmar fascia that causes flexion contractures in the fingers, is prevalent in people of North-Western European descent and less so in other ethnicities. DD is a complex disorder, influenced by genetic risk variants. We aimed to study if the marked differences in prevalences in DD between ethnic (sub)groups could be explained by differences in allele frequencies of the 26 known genetic risk variants of DD. Therefore, genetic risk scores (GRS) composed of the 26 DD risk variants were calculated for the 26 populations from the 1000 Genomes database and correlated to observed DD prevalences from literature. For comparison, GRSs were generated for 10,000 sets of 26 random SNPs and also correlated to the observed DD prevalences to determine the significance of the observed correlation. To determine whether differences in allele frequencies between ethnicities were caused by natural selection, fixation indices (Fst) were calculated from the 26 SNPs and from the sets of 26 random SNPs for comparison. Observed prevalences could be determined from literature for 10 populations. Their correlation with the GRS composed of DD SNPs proved to be 0.60 (p = 0.0003). The Fsts between British and other populations were low for European, ad mixed American, and South-Asian populations, and moderate for East-Asians. African populations were significantly different from expected values determined from the random sets. In conclusion, the 26 known genetic risk variants associated with DD explain for a substantial part (R2 = 0.36) the differing DD prevalences observed between ethnicities.

Interleukin 6 decreases nociceptor expression of the potassium channel KV1.4 in a rat model of hand-arm vibration syndrome

Chronic muscle pain is a prominent symptom of the hand-arm vibration syndrome (HAVS), an occupational disease induced by exposure to vibrating power tools, but the underlying mechanism remains unknown. We evaluated the hypothesis that vibration induces an interleukin 6 (IL-6)-mediated downregulation of the potassium voltage-gated channel subfamily A member 4 (KV1.4) in nociceptors leading to muscle pain. Adult male rats were submitted to a protocol of mechanical vibration of the right hind limb. Twenty-four hours after vibration, muscle hyperalgesia was observed, concomitant to increased levels of IL-6 in the gastrocnemius muscle and decreased expression of KV1.4 in the dorsal root ganglia. Local injection of neutralizing antibodies against IL-6 attenuated the muscle hyperalgesia induced by vibration, whereas antisense knockdown of this channel in the dorsal root ganglia mimicked the muscle hyperalgesia observed in the model of HAVS. Finally, knockdown of the IL-6 receptor signaling subunit glycoprotein 130 (gp130) attenuated both vibration-induced muscle hyperalgesia and downregulation of KV1.4. These results support the hypothesis that IL-6 plays a central role in the induction of muscle pain in HAVS. This likely occurs through intracellular signaling downstream to the IL-6 receptor subunit gp130, which decreases the expression of KV1.4 in nociceptors.

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.

Risk assessment of vascular disorders by a supplementary hand-arm vascular weighting of hand-transmitted vibration

PURPOSE

To provide an updated epidemiological validation for a supplementary method for assessing the risk of vascular disorders from hand-transmitted vibration.

METHODS

The occurrence of vibration-induced white finger (VWF) in the vibration-exposed workers of the Italian cohort of the EU VIBRISKS study was related to measures of daily vibration exposure expressed in terms of r.m.s. acceleration magnitude normalised to an 8-h day, frequency weighted according to either the frequency weighting W_h defined in international standard ISO 5349-1:2001 [A_h(8) in ms^- 2] or the hand-arm vascular frequency weighting W_p proposed in the ISO technical report (TR) 18570:2017 [A_p(8) in ms^- 2]. To estimate a threshold value for vascular hand-arm vibration risk, the W_p-weighted vibration exposure value E_p,d (in ms^- 1.5) was calculated according to the ISO/TR document. The difference in the predictions of VWF between the exposure measures calculated with the frequency weightings W_h or W_p was investigated by means of logistic modelling.

RESULTS

Measures of daily vibration exposure constructed with the frequency weighting W_p [A_p(8) and E_p,d], which gives more importance to intermediate- and high-frequency vibration, were better predictors of the occurrence of VWF in the vibration-exposed workers than the metric derived from the conventional ISO frequency weighting W_h [A_h(8)]. There was some epidemiological evidence for a threshold value of E_p,d for the onset of VWF in the vibration-exposed workers.

CONCLUSIONS

Measures of daily vibration exposure evaluated with the vascular weighting W_p performed better for the predictions of VWF than those obtained with the frequency weighting W_h recommended in ISO 5349-1.

Raynaud's phenomenon: Current concepts

Raynaud's phenomenon (RP) is a transient, acral, vasospastic phenomenon that manifests with characteristic color changes. This vasospasm, classically triggered by cold temperatures, may also be driven by shifts in temperature, climate, or emotional state. Primary RP (PRP) is a common condition without severe sequelae. Secondary RP (SRP), which may be driven by vascular, autoimmune, hematologic, or endocrine etiologies, can result in digital ulceration, irreversible ischemia and necrosis, and secondary infection. This review delineates the clinical manifestations of both primary and secondary RP, as well as the current understanding of RP epidemiology and pathogenesis. Proper examination, including nailfold capillary microscopy, and laboratory workup for secondary causes of RP are also discussed. The traditional armamentarium of therapies used for RP, as well as newer medical and surgical options, is also summarized with particular regard to the clinical evidence for their efficacy.

Dupuytren's contracture and handwork: A case-control study

OBJECTIVE

The objective of this study was to examine the association between Dupuytren's contracture (DC), repetitive handwork (RHW), heavy handwork (HHW), and/or vibration exposure.

METHODS

Frequency and intensity of the three types of handwork were collected and compared between DC patients and controls. Hours of work were weighted by average "frequency," for RHW, and average "intensity," for HHW and use of vibrating tool. Logistic regression was used to evaluate risk of developing DC associated with the above-mentioned factors.

RESULTS

Data from 129 cases (74 clinical, 106 controls) was analyzed. Family history, male gender and age (decades) were associated with increased risk of DC. Results indicate that the risk becomes substantial after about 30 years of steady RHW. Independent effects of intensity-weighted HHW and vibrating exposure were not established.

CONCLUSIONS

Frequency-weighted RHW increases DC risk. Additionally, a strong association between DC, male gender and heredity was found.

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.

Dupuytren disease is highly prevalent in male field hockey players aged over 60 years

BACKGROUND/AIM

Dupuytren disease is a fibroproliferative hand condition. The role of exposure to vibration as a risk factor has been studied with contradictory results. Since field hockey is expected to be a strong source of hand-arm vibration, we hypothesised that long-term exposure to field hockey is associated with Dupuytren disease.

METHODS

In this cross-sectional cohort study, the hands of 169 male field hockey players (IQR: 65-71 years) and 156 male controls (IQR: 59-71 years) were examined for signs of Dupuytren disease. Details about their age, lifestyle factors, medical history, employment history and leisure activities were gathered. Prior to the analyses, the groups were balanced in risk factors using propensity score matching. The association between field hockey and Dupuytren disease was determined using a subject-specific generalised linear mixed model with a binomial distribution and logit link function (matched pairs analysis).

RESULTS

Dupuytren disease was observed in 51.7% of the field hockey players, and in 13.8% of the controls. After propensity score matching, field hockey playing as dichotomous variable, was associated with Dupuytren disease (OR=9.42, 95% CI 3.01 to 29.53). A linear dose-response effect of field hockey (hours/week x years) within the field hockey players could not be demonstrated (OR=1.03, 95% CI 0.68 to 1.56).

DISCUSSION

We found that field hockey playing has a strong association with the presence of Dupuytren disease. Clinicians in sports medicine should be alert to this less common diagnosis in this sport.

Rheumatic effects of vibration at work

Occupational exposures to vibration come in many guises, and they are very common at a population level. It follows that an important minority of working-aged patients seen by medical services will have been exposed to this hazard of employment. Vibration can cause human health effects, which may manifest in the patients that rheumatologists see. In this chapter, we identify the health effects of relevance to them, and review their epidemiology, pathophysiology, clinical presentation, differential diagnosis and vocational and clinical management. On either side of this, we describe the nature and assessment of the hazard, the scale and common patterns of exposure to vibration in the community and the legal basis for controlling health risks, and we comment on the role of health surveillance in detecting early adverse effects and what can be done to prevent the rheumatic effects of vibration at work.

Associations between workplace factors and carpal tunnel syndrome: A multi-site cross sectional study

BACKGROUND

Few large epidemiologic studies have used rigorous case criteria, individual-level exposure measurements, and appropriate control for confounders to examine associations between workplace psychosocial and biomechanical factors and carpal tunnel syndrome (CTS).

METHODS

Pooling data from five independent research studies, we assessed associations between prevalent CTS and personal, work psychosocial, and biomechanical factors while adjusting for confounders using multivariable logistic regression.

RESULTS

Prevalent CTS was associated with personal factors of older age, obesity, female sex, medical conditions, previous distal upper extremity disorders, workplace measures of peak forceful hand activity, a composite measure of force and repetition (ACGIH Threshold Limit Value for Hand Activity Level), and hand vibration.

CONCLUSIONS

In this cross-sectional analysis of production and service workers, CTS prevalence was associated with workplace and biomechanical factors. The findings were similar to those from a prospective analysis of the same cohort with differences that may be due to recall bias and other factors.

A systematic review and meta-analysis on the prevalence of Dupuytren disease in the general population of Western countries

BACKGROUND

Dupuytren disease is a fibroproliferative disease of palmar fascia of the hand. Its prevalence has been the subject of several reviews; however, an accurate description of the prevalence range in the general population--and of the relation between age and disease--is lacking.

METHODS

Embase and PubMed were searched using database-specific Medical Subject Headings; titles and abstracts were searched for the words "Dupuytren," "incidence," and "prevalence." Two reviewers independently assessed the articles using inclusion and exclusion criteria, and rated the included studies with a quality assessment instrument. In a meta-analysis, the median prevalence, as a function of age by sex, was estimated, accompanied by 95 percent prediction intervals. The observed heterogeneity in prevalence was investigated with respect to study quality and geographic location.

RESULTS

Twenty-three of 199 unique identified articles were included. The number of participants ranged from 37 to 97,537, and age ranged from 18 to 100 years. Prevalence varied from 0.6 to 31.6 percent. The quality of studies differed but could not explain the heterogeneity among studies. Mean prevalence was estimated as 12, 21, and 29 percent at ages 55, 65, and 75 years, respectively, based on the relation between age and prevalence determined from 10 studies.

CONCLUSIONS

The authors describe a prevalence range of Dupuytren disease in the general population of Western countries. The relation between age and prevalence of Dupuytren disease is given according to sex, including 95 percent prediction intervals. It is possible to determine disease prevalence at a certain age for the total population, and for men and women separately.

Association among work exposure, alcohol intake, smoking and Dupuytren's disease in a large cohort study (GAZEL)

OBJECTIVES

In view of the debate of factors in Dupuytren's disease, we aimed to describe its relationship with certain occupational factors, alcohol intake and smoking.

SETTING

The French GAZEL cohort (employees of Electricité de France and Gaz de France).

PARTICIPANTS

Participants of the cohort who answered a questionnaire in 2012, that is, 13 587 participants (73.7% of the questionnaire sent). In 2007, self-assessed lifetime occupational biomechanical exposure was recorded (carrying loads, manipulating a vibrating tool and climbing stairs), as well as alcohol intake, smoking and diabetes mellitus. Analyses were performed on high alcohol intake, smoking and duration of relevant work exposure, stratified by gender.

PRIMARY AND SECONDARY OUTCOME MEASURES

From a specific question on Dupuytren's disease assessed in 2012, the outcome measures were self-reported Dupuytren's disease (yes/no) and disabling Dupuytren's disease (including surgery).

RESULTS

A total of 10 017 men and 3570 women, aged 64-73 years, were included; the mean age for men was 68 years and for women was 65 years. Among men, the following were significantly associated with Dupuytren's disease: age (OR 1.03 (1.00; 1.06)), diabetes (OR 1.31 (1.07; 1.60)), heavy drinking (OR 1.36 (1.10; 1.69)) and over 15 years of manipulating a vibrating tool at work (OR 1.52 (1.15; 2.02)); except for diabetes, the association with these factors was stronger for disabling Dupuytren's disease (or surgery), with OR 1.07 (1.03; 1.11), 1.71 (1.25; 2.33) and 1.98(1.34; 2.91), respectively, for age, heavy drinking and over 15 years of manipulating a vibrating tool at work. Among the 3570 women included, 160 reported Dupuytren's disease (4.5%). The number of cases in the group of women was too low to reach conclusions, although the findings seemed similar for age, diabetes and vibration exposure.

CONCLUSIONS

In this large French cohort study, Dupuytren's disease in men was associated with high levels of alcohol consumption and exposure to hand-transmitted vibration. It is likely that the same applied to women.

Dupuytren's contracture and occupational exposure to hand-transmitted vibration

AIMS

The relation between Dupuytren's contracture and occupational exposure to hand-transmitted vibration (HTV) has frequently been debated. We explored associations in a representative national sample of workers with well-characterised exposure to HTV.

METHODS

We mailed a questionnaire to 21 201 subjects aged 16-64 years, selected at random from the age-sex registers of 34 general practices in Great Britain and to 993 subjects chosen randomly from military pay records, asking about occupational exposure to 39 sources of HTV and about fixed flexion contracture of the little or ring finger. Analysis was restricted to men at work in the previous week. Estimates were made of average daily vibration dose (A(8) root mean squared velocity (rms)) over that week. Associations with Dupuytren's contracture were estimated by Poisson regression, for lifetime exposure to HTV and for exposures in the past week >A(8) of 2.8 ms(-2) rms. Estimates of relative risk (prevalence ratio (PR)) were adjusted for age, smoking status, social class and certain manual activities at work.

RESULTS

In all 4969 eligible male respondents supplied full information on the study variables. These included 72 men with Dupuytren's contracture, 2287 with occupational exposure to HTV and 409 with A(8)>2.8 ms(-2) in the past week. PRs for occupational exposure to HTV were elevated 1.5-fold. For men with an A(8)>2.8 ms(-2) in the past week, the adjusted PR was 2.85 (95% CI 1.37 to 5.97).

CONCLUSIONS

Our findings suggest that risk of Dupuytren's contracture is more than doubled in men with high levels of weekly exposure to HTV.

Heavy manual work, exposure to vibration and Dupuytren's disease? Results of a surveillance program for musculoskeletal disorders

INTRODUCTION

This study aimed to determine the prevalence of Dupuytren's disease in men and its relationship with work exposure, particularly heavy manual work with and without significant use of vibrating tools, using data from a surveillance program for musculoskeletal disorders.

METHOD

This cross-sectional study was conducted in France between 2002 and 2005. Dupuytren's disease was diagnosed clinically by one of 83 occupational physicians. Exposure in relation to work status and occupational risk factors was assessed with a self-administered questionnaire, and categorised according to vibration exposure (defined as use of vibrating tools for ≥2 h/day), heavy manual work without vibration exposure (defined as use of hand tools for ≥2 h/day (use of vibrating tools for ≥2 h/day excluded) and Borg scale ≥15/20) and no such exposure. Bivariate and multivariate associations using logistic models were recorded in men and in those with >10 years in the same job.

RESULTS

Of 2161 men, 1.3% (n=27) had Dupuytren's disease (mean age 47.1±6.7 years). Heavy manual work without vibration exposure was significantly associated with the condition (adjusted OR (aOR) 3.9; 95% CI 1.3 to 11.5) adjusted on age and diabetes), as was use of vibrating tools (aOR 5.1; 2.1 to 12.2). These associations remained significant among subjects with >10 years in the same job, with increases in aOR of 6.1 (1.5 to 25.0) and 10.7 (3.4 to 34.6), respectively.

CONCLUSION

Despite the limited number of cases, occupational exposure, including both vibration exposure and heavy manual work without significant vibration exposure, was associated with Dupuytren's disease.

Carpal tunnel syndrome and its relationship to occupation: a meta-analysis

OBJECTIVE

To examine the association between work place exposure and CTS by meta-analysis, including analyses with respect to exposure to hand force, repetition, vibration and wrist posture.

METHODS

All relevant peer-reviewed articles published between January 1980 and December 2009 were identified by a systematic search using the MEDLINE, CINAHL and PubMed databases. Papers were critiqued independently by two researchers and the relevant exposure information was extracted. Using the raw data of exposed and unexposed cases, a cumulative effect of specific exposure risks were calculated for hand force, repetition, a combination of force and repetition, vibration and wrist posture using the statistical program, Stata version 11 (StataCorp, College Station, TX, USA). Heterogeneity, meta-regression, publication bias and subgroup sensitivity analyses were performed.

RESULTS

Thirty-seven studies from English-language literature met the inclusion criteria. Using National Institute for Occupational Health and Safety criteria for case definition, a significant positive association between CTS and hand force, repetition, use of vibratory tools and wrist posture was observed with approximate doubling of risk for all exposures. Significant heterogeneity among studies was observed for most exposures and metaregression analyses identified CTS case definition, study design, country and risk of bias score to be the significant determinants. When a more conservative definition of CTS was employed to include nerve conduction abnormality with symptoms and/or signs, risk factors significantly associated with an increased risk of CTS among exposed workers were: vibration [odds ratio (OR) 5.40; 95% CI 3.14, 9.31], hand force (OR 4.23; 95% CI 1.53, 11.68) and repetition (OR 2.26; 95% CI 1.73, 2.94). There was a non-significant trend for the association between CTS and combined exposure to both force and repetition (OR 1.85; 95% CI 0.99, 3.45) and wrist posture (OR 4.73; 95% CI 0.42, 53.32).

CONCLUSION

Occupational exposure to excess vibration, increased hand force and repetition increase the risk of developing CTS. Workplace strategies to avoid overexposure to these risk factors should be implemented.

Should we consider Dupuytren's contracture as work-related? A review and meta-analysis of an old debate

BACKGROUND

In view of the conflicting opinions published, a meta-analysis was undertaken on epidemiological studies in order to assess any association between Dupuytren's contracture and work exposure.

METHODS

Using the key words: "occupational disease", "work" and "Dupuytren contracture" without limitation on language or year of publication, epidemiological studies were selected from four databases (Pub-Med, Embase, Web of science, BDSP) after two rounds (valid control group, valid work exposure). A quality assessment list was constructed and used to isolate papers with high quality methodological criteria (scores of 13 or above, HQMC). Relevant associations between manual work, vibration exposure (at work) and Dupuytren's contracture were extracted from the articles and a metarisk calculated using the generic variance approach (meta-odds ratios, meta-OR).

RESULTS

From 1951 to 2007, 14 epidemiological studies (including 2 cohort studies, 3 case-control studies, and 9 cross-sectional studies/population surveys) were included. Two different results could be extracted from five studies (based on different types of exposure), leading to 19 results, 12 for manual work (9 studies), and 7 for vibration exposure (5 studies). Six studies met the HQMC, yielding 9 results, 5 for manual work and 4 for vibration exposure. Five studies found a dose-response relationship. The meta-OR for manual work was 2.02[1.57;2.60] (HQMC studies only: 2.01[1.51;2.66]), and the meta-OR for vibration exposure was 2.88 [1.36;6.07] (HQMC studies only: 2.14[1.59;2.88]).

CONCLUSION

These results support the hypothesis of an association between high levels of work exposure (manual work and vibration exposure) and Dupuytren's contracture in certain cases.

A case report of vibration-induced hand comorbidities in a postwoman

Background

Prolonged exposure to hand-transmitted vibration is associated with an increased occurrence of symptoms and signs of disorders in the vascular, neurological and osteoarticular systems of the upper limbs. However, the available epidemiological evidence is derived from studies on high vibration levels caused by vibratory tools, whereas little is known about possible upper limb disorders caused by chronic exposure to low vibration levels emitted by fixed sources.

Case presentation

We present the case of a postwoman who delivered mail for 15 years using a low-powered motorcycle. The woman was in good health until 2002, when she was diagnosed with bilateral Raynaud's phenomenon. In March 2003 a bilateral carpal tunnel syndrome was electromyographically diagnosed; surgical treatment was ineffective. Further examinations in 2005 highlighted the presence of chronic tendonitis (right middle finger flexor).

Risk assessment

From 1987, for 15 years, our patient rode her motorcycle for 4 h/day, carrying a load of 20-30 kg. For about a quarter of the time she drove over country roads. Using the information collected about the tasks carried out every day by the postwoman and some measurements performed on both handles of the motorcycle, as well as on both iron parts of the handlebars, we reconstructed the woman's previous exposure to hand-arm vibration. 8-hour energy-equivalent frequency weighted acceleration was about 2.4 m/s². The lifetime dose was 1.5 × 10⁹(m²/s⁴)hd.

Conclusions

The particular set of comorbidities presented by our patient suggests a common pathophysiological basis for all the diseases. Considering the level of exposure to vibrations and the lack of specific knowledge on the effects of vibration in women, we hypothesize an association between the work exposure and the onset of the diseases.

Carpal tunnel syndrome: the role of occupational factors

Carpal tunnel syndrome (CTS) is a fairly common condition in working-aged people, sometimes caused by physical occupational activities, such as repeated and forceful movements of the hand and wrist or use of hand-held, powered, vibratory tools. Symptoms may be prevented or alleviated by primary control measures at work, and some cases of disease are compensable. Following a general description of the disorder, its epidemiology and some of the difficulties surrounding diagnosis, this review focusses on the role of occupational factors in causation of CTS and factors that can mitigate risk. Areas of uncertainty, debate and research interest are emphasised where relevant.

The emerging role of Clostridium histolyticum collagenase in the treatment of Dupuytren disease

Dupuytren disease (DD) is a common fibroproliferative disease of unknown etiopathogenesis affecting the palmar aponeurosis, causing reduced hand function and resulting in fixed flexion contractures of the digits. Current gold standard treatment for the management of DD is surgical excision involving removal of the affected palmar fascial tissue. However, there are potential complications associated with surgery as it is costly and a positive surgical outcome is often short-lived because the disease tends to recur. Therefore, there is growing interest in nonsurgical, outpatient-based treatments that could be quicker, cheaper, reduce morbidity, show a decreased rate of recurrence, and give DD patients an improved quality of life when compared with traditional surgical management. Of the available nonsurgical options, injectable Clostridium histolyticum collagenase (CHC) has received recent clinical interest. In this article, a brief overview of DD surgical and nonsurgical treatments utilized is given, followed by a detailed examination of the nine papers published to date on the use of CHC in DD (and similar fibrotic disorders). These papers have investigated safe and efficacious doses for the injection of CHC to treat palpable DD cords in adult patients and have shown significant short- to mid-term results for correction to near-full digital extension (≤5° extension) following CHC injection of DD cords. CHC has been shown to target the collagen-based DD cords while sparing surrounding neurovasculature, with a complication profile that appears comparable to that of the surgical methods currently utilized. In conclusion, clostridial collagenase is a novel nonsurgical treatment option of considerable potential in the management of DD when administered by specialist hand surgeons with detailed knowledge of the disease and the relevant anatomy. Nonetheless, there is a need for further data on long-term results, complications, and rate of recurrence with the use of this emerging treatment option.

A longitudinal study of vibration white finger, cold response of digital arteries, and measures of daily vibration exposure

PURPOSE

To investigate prospectively the relation between vibration-induced vascular disorders and measures of daily exposure to hand-transmitted vibration (HTV).

METHODS

Two hundred and forty-nine HTV workers and 138 control men of the same companies participated in a 3-year follow-up study. The diagnosis of vibration induced white finger (VWF) in the HTV workers and that of Raynaud's phenomenon in the controls was based on the medical history, the administration of color charts and the results of a cold test with measurement of finger systolic blood pressures. Vibration magnitudes from the tools were measured as r.m.s acceleration, frequency weighted according to international standard ISO 5349-1, and also unweighted over the frequency range 6.3-1,250 Hz. Daily vibration exposure was expressed in terms of daily exposure duration and frequency-weighted or unweighted r.m.s. acceleration normalized to a reference period of 8 h (Aw(8) or Auw(8), respectively).

RESULTS

The incidence of VWF varied from 5 to 6% in the HTV workers versus 0-1.5% for Raynaud's phenomenon in the controls. After adjusting for potential confounders, Auw(8) gave better predictions of the incidence of VWF and the cold response of the digital arteries over time than Aw(8) or daily exposure duration. These findings were observed in the entire sample of HTV workers, in those with no VWF at the initial investigation, and in those with normal cold test results at baseline.

CONCLUSIONS

The findings of this longitudinal study suggest that a measure of daily vibration exposure calculated from unweighted r.m.s. acceleration over the frequency range 6.3-1,250 Hz performs better for the prediction of vascular disorders in users of vibratory tools than a measure derived from r.m.s. acceleration frequency weighted according to ISO 5349-1. This study provides epidemiological evidence that more weight should be given to intermediate and high-frequency vibration for evaluating the severity of hand-transmitted vibration.

Epidemiological evaluation of Dupuytren's disease incidence and prevalence rates in relation to etiology

Dupuytren's Disease (DD) is a common, fibroproliferative disorder affecting the palmar surface of the hands which is often irreversible and progressive. Understanding the epidemiology of DD is important in order to provide clues to its etiopathogenesis. This review aims to evaluate the epidemiological studies carried out in DD since 1951. Studies evaluating the epidemiology of DD were searched using Medline, Pubmed, and Scopus which dated back from 1951 to current date. Inclusion criteria were any studies investigating the prevalence or incidence of DD in any population group. A total of 620 articles were cited. Forty-nine studies were subsequently identified as relevant to evaluating the epidemiology of DD. The prevalence of DD in all studies increased with age with a male to female ratio of approximately 5.9:1. Prevalence rates ranged from 0.2% to 56% in varying age, population groups, and methods of data collection. The highest prevalence rate was reported in a study group of epileptic patients. Although, only one study calculated the incidence (as opposed to prevalence) of DD to be equal to 34.3 per 100,000 men (0.03%). In conclusion, the prevalence of DD in different geographical locations is extremely variable, and it is not clear whether this is genetic, environmental, or a combination of both. The majority of the prevalence studies have been conducted in Scandinavia or the UK, and the vast changes in population structure, the changes in prevalence of associated diseases, and the change in diagnostic criteria of DD makes understanding the epidemiology of this condition difficult.

Effect of the magnitude and frequency of hand-transmitted vibration on finger blood flow during and after exposure to vibration

BACKGROUND

Acute exposures of the hand to vibration result in changes in finger blood flow, but it is not clear how the changes depend on the characteristics of the vibration.

OBJECTIVES

To determine the effects of the magnitude and frequency of hand-transmitted vibration on finger blood flow in an exposed and a non-exposed hand during and after exposure to vibration.

METHODS

Twelve persons attended seven sessions consisting of five successive periods: (1) no force and no vibration, (2) force and no vibration, (3) force and vibration, (4) force and no vibration, and (5) no force and no vibration. During the second, third and fourth periods, the palm of the right hand applied a 2-N downward force on a 25-mm diameter convex platform. During the third period, the platform was vibrated at either 16, 31.5, 63, 125, 250, or 315 Hz with the vibration magnitude increasing linearly from 0 to 15 ms(-2) rms (frequency-weighted) over 30 min (0-11 ms(-2) rms at 315 Hz). Finger blood flow was measured in the middle and little fingers of the right (exposed) hand and the middle finger of the left (unexposed) hand.

RESULTS

The application of 2-N force by the palm did not affect finger blood flow on either the exposed hand or the unexposed hand. Blood flow in all three fingers (both exposed and not exposed to vibration) reduced similarly with increasing vibration magnitude, with the greatest reduction to about 40% of finger blood flow before vibration exposure. During vibration at the same frequency-weighted acceleration according to current standards, finger blood flow was dependent on the vibration frequency, with vibration at 125, 250 and 315 Hz causing the greatest reductions in finger blood flow. With vibration at 250 Hz and 315 Hz, frequency-weighted accelerations less than 1.0 ms(-2) rms reduced finger blood flow, whereas greater magnitudes were required at the lower frequencies. After the cessation of vibration, finger blood flow in exposed and unexposed fingers also depended on the vibration frequency, with greater vasoconstriction after exposure to the higher frequencies.

CONCLUSIONS

During exposure to vibration, vasoconstriction in the fingers depends on both the frequency and the magnitude of the vibration. Finger blood flow was reduced by vibration magnitudes much lower than those on many powered hand tools. Vibration of one hand produced a similar vasoconstriction in fingers on the exposed and unexposed hand, suggesting a centrally mediated response. After cessation of vibration, there is continued vasoconstriction that depends on the frequency and magnitude of the prior vibration, with a similar effect in exposed and non-exposed hands.

Upper extremity disability in workers with hand-arm vibration syndrome

BACKGROUND

Hand-arm vibration syndrome (HAVS) is a common occupational problem and it is important to understand the disability associated with this condition.

AIMS

To measure upper extremity disability using the disabilities of the arm, shoulder and hand (DASH) questionnaire in workers with HAVS and to determine how this disability is affected by the vascular and neurological components of HAVS and other factors, in particular musculoskeletal variables.

METHODS

Subjects were recruited from HAVS patients assessed at St Michael's Hospital, Toronto, Canada, over a 2-year period. All participants were assessed by an occupational medicine specialist to determine the specific components of HAVS and musculoskeletal variables including upper extremity pain score measured by the Borg scale. The DASH questionnaire was completed on the same day as the clinical assessment and before any feedback had been given about the clinical findings.

RESULTS

A total of 141 workers with HAVS were recruited and 139 agreed to participate in the study. This study group had a statistically significantly higher mean DASH score than the US population (P < 0.001). The multiple linear regression analysis indicated that upper extremity pain score (P < 0.001), the Stockholm sensorineural scale (P < 0.01) and the number of fingers blanching (P < 0.05) had a statistically significant association with an increase in the DASH score. The highest partial R(2) value was for the upper extremity pain score.

CONCLUSIONS

Workers with HAVS have significant upper extremity disability and musculoskeletal factors appear to make an important contribution to this disability.

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.

Diagnosing soft tissue rheumatic disorders of the upper limb in epidemiological studies of vibration-exposed populations

OBJECTIVES

To investigate approaches adopted to diagnose soft tissue rheumatic disorders of the upper limb (ULDs) in vibration-exposed populations and in other settings, and to compare their methodological qualities.

METHODS

Systematic searches were made of the Medline, Embase, and CINAHL electronic bibliographic databases, and of various supplementary sources (textbooks, reviews, conference and workshop proceedings, personal files). For vibration-exposed populations, qualifying papers were scored in terms of the provenance of their measuring instruments (adequacy of documentation, standardisation, reliability, criterion-related and content validity). Similar criteria were applied to general proposals for whole diagnostic schemes, and evidence was collated on the test-retest reliability of symptom histories and clinical signs.

RESULTS

In total, 23 relevant reports were identified concerning vibration-exposed populations--21 involving symptoms and 9 involving examination/diagnosis. Most of the instruments employed scored poorly in terms of methodological quality. The search also identified, from the wider literature, more than a dozen schemes directed at classifying ULDs, and 18 studies of test-retest reliability of symptoms and physical signs in the upper limb. Findings support the use of the standardised Nordic questionnaire for symptom inquiry and suggest that a range of physical signs can be elicited with reasonable between-observer agreement. Four classification schemes rated well in terms of content validity. One of these had excellent documentation, and one had been tested for repeatability, agreement with an external reference standard, and utility in distinguishing groups that differed in disability, prognosis and associated risk factors.

CONCLUSIONS

Hitherto, most studies of ULDs in vibration-exposed populations have used custom-specified diagnostic methods, poorly documented, and non-stringent in terms of standardisation and supporting evidence of reliability and/or validity. The broader literature contains several question sets and procedures that improve upon this, and offer scope in vibration-exposed populations to diagnose ULDs more systematically.

Dupuytren's disease: personal factors and occupational exposure

BACKGROUND

The etiology of Dupuytren's disease is unknown, and the role of occupational exposure is still debated. Our objective was to study the association between occupational exposures, personal risk factors and Dupuytren's disease.

METHODS

In this cross-sectional survey, nine occupational physicians performed clinical examinations, focused on Dupuytren's disease, of 2,406 French male civil servants employed at the Equipment Ministry in 1998 and interviewed them about medical history, leisure manual exposure and occupational biomechanical exposure to vibrations and manual work. A cumulative occupational exposure score was defined, with three levels of exposure.

RESULTS

Dupuytren's disease was diagnosed in 212 men (8.8%). The occupational exposure score was significantly higher in this group of cases than in the rest of the sample (377 (SD280) vs. 223 (SD250), respectively; P < 0.0001). Occupational exposure was associated with Dupuytren's disease (adjusted Odds Ratio = 2.20 [1.39-3.45] for the intermediate and 3.10 [1.99-4.84] for the high exposure groups), with adjustment for age, leisure physical activities, alcohol consumption (> or =5 servings per day), history of diabetes, epilepsy, hand trauma, and familial history of Dupuytren's disease.

CONCLUSION

Manual work exposure was associated with Dupuytren's disease after adjustment for personal risk factors. Longitudinal studies are needed to confirm these results.

An assessment of the effects of exposure to vibration, smoking, alcohol and diabetes on the prevalence of Dupuytren's disease in 97,537 miners

A consecutive sample of 97,537 miners seeking compensation for Hand-Arm Vibration Syndrome were examined in a medical assessment process which included documentation of age, hand dominance, Dupuytren's disease, years of vibration exposure, history of diabetes, smoking habits and units of alcohol consumption per week. The prime determinant of prevalence of Dupuytren's disease was age, and all other factors investigated were corrected for age. There was no statistically significant correlation between years of exposure to vibration and the prevalence of Dupuytren's disease. There was a statistically significant association with smoking, alcohol consumption and diabetes mellitus, with the heaviest smokers having an odds ratio (OR) of 1.31 (95% CI, 1.17, 1.47), the heaviest drinkers (in excess of 22 units a week) having an OR of 1.59 (95% CI, 1.47, 1.72) and diabetes mellitus patients having an increase in the odds of having Dupuytren's disease of 1.52 (95% CI 1.30, 1.77).

The Hand-Arm Vibration International Consortium (HAVIC): Prospective Studies on the Relationship Between Power Tool Exposure and Health Effects

OBJECTIVES

The Hand-Arm Vibration International Consortium (HAVIC) is a collaboration of investigators from Europe and North America studying health effects from hand-arm vibration (HAV). Features include prospective design, cross-cohort exposure, and health assessment methods.

METHODS

Two new cohorts (dental hygienists and dental hygiene students), two existing cohorts (Finnish forest workers, and Swedish truck cab assemblers), and a previous population (US shipyard workers) are included. Instruments include surveys, quantitative medical tests, physical examination, and work simulation and data logging to assess exposure. New methods were developed for nerve conduction and data logging.

RESULTS

Findings on the relationship between nerve conduction and skin temperature in HAV-exposed subjects resulted in a new approach to subject warming.

CONCLUSIONS

Integrating established cohorts has advantages over de novo cohort construction. Complex laboratory tests can be successfully adapted for field use.

[Raynaud's phenomenon]

Raynaud's phenomenon is characterized by repeated daily attacks of ischemia followed by reperfusion at the acrallevel. It is a frequent syndrome found in medical practice; and it can be considered as primary or secondary to other conditions, including rheumatic autoimmune diseases. Current classification had clinical and therapeutic implications. Careful clinical evaluation is the most reliable and reproducible method in the diagnosis of Raynaud's phenomenon. Several risk factors had been associated in the genesis of Raynaud's phenomenon; however, its pathogenesis remains elusive although recently, considerable progress in disease mechanism had been described. Such advances are directing new lines of therapy.