Relationship between hand-arm vibration exposure and onset time for symptoms in a heavy engineering production workshop

Hand-arm vibration syndrome among harvesting farmers: A cross-sectional study from Pakistan

BACKGROUND

Constant use of hand-held vibratory tools may cause health issues, including hand dysfunction, among farmers. Thus, exposure to these vibratory instruments may cause hand-arm vibration syndrome (HAVS).

OBJECTIVE

The study aimed to measure the prevalence of HAVS and evaluate neurological and vascular symptoms among farmers.

METHODS

This cross-sectional study included 20 villages in Pakistan and used a three-part questionnaire to collect data from farmers exposed to vibration while farming. The study included demographics, the Health Surveillance Questionnaire, and the Stockholm Workshop Classification Scale. SPSS version 22 was used for the data entry and statistical analysis.

RESULTS

433 (43%) participants had musculoskeletal discomfort and 568 (57%) had hand vibration. Raynaud phenomenon was evident in 430 (43%) participants, whereas carpal tunnel syndrome was found in 218 (22%). Tingling was reported by 255 participants (26%), and numbness was reported by 543 (54%). According to the grading of neurological symptoms, 461 (46%) participants were exposed to vibration but did not experience any symptoms, placing them in stage 0. 185 (18.5%) participants with HAVS with infrequent episodes affecting just the tips of one or more fingers were categorized in stage 01 based on grading of vascular symptoms.

CONCLUSION

HAVS are common among harvesting farmers, with the most noticeable vibrations occurring in the shoulder region. Similarly, most farmers had no vascular symptoms, and most were exposed to vibration but had no neurological symptoms.

Tremor measurements in a 22-year cohort study of workers exposed to hand-held vibrating tools

OBJECTIVES

The objectives of this cohort study were to evaluate possible long-term effects of occupational exposure to hand-arm vibration (HAV) in terms of increased tremor. The aims were to evaluate whether exposure during follow-up, baseline hand-arm vibration syndrome (HAVS), baseline manual dexterity or current medical conditions or life-style habits might be associated with increased tremor. A further aim was to compare two different activation conditions: postural vs rest tremor.

METHODS

Forty men (current age: 60.4 years) who had previously worked as manual workers in a specialized engineering and construction company enrolled in the study. Their hand functions had been examined in 1994. At the baseline examination, 27 had been diagnosed with HAVS, while 13 were not exposed. The follow-up examination in 2016-2017 comprised the CATSYS Tremor Pen^® for measuring postural and rest tremor and the Grooved Pegboard Test for assessing manual dexterity. Blood samples were taken for assessing biomarkers that might have impact on tremor.

RESULTS

Neither cumulative exposure to HAV during follow-up nor HAVS at baseline were associated with increased tremor. A test for manual dexterity at baseline was significantly associated with increased tremor (Tremor Intensity) at follow-up. Blood markers of current medical conditions and tobacco consumption were associated with increased tremor. Rest tremor frequency was higher than postural tremor frequency (p < 0.001).

CONCLUSIONS

The main findings of this 22-year cohort study were no indications of long-term effects on tremor related to HAV exposure and previous HAVS status. However, baseline manual dexterity was significantly associated with increased tremor at follow-up. Activation conditions (e.g., hand position) are important when testing tremor.

Tremor and hand-arm vibration syndrome (HAVS) in road maintenance workers

Objectives

The aim of this study was to evaluate postural and rest tremor among workers using vibrating hand tools, taking into account the possible effects of toxicants such as alcohol and tobacco. A further aim was to study workers diagnosed with hand-arm vibration syndrome (HAVS) at the time of examination.

Methods

This study comprises 103 road maintenance workers, 55 exposed to vibrating hand tools (age 41.0 years; range 21–62) and 48 referents (age 38.5 years; range 19–64). They were examined with the CATSYS Tremor Pen^®. Exposure to vibrating tools and serum biomarkers of alcohol and tobacco consumption were measured.

Results

Cumulative exposure to vibrating tools was associated with increased postural (p < 0.01) and rest tremor (p < 0.05) and with a higher Center Frequency of postural tremor (p < 0.01) among smokers and users of smokeless tobacco. Rest tremor Center Frequency was higher than postural tremor frequency (p < 0.001).

Conclusions

The main findings indicate an association between cumulative exposure to hand-held vibrating tools, tremor parameters and consumption of tobacco products. The hand position is important when testing for tremor. Rest tremor had a higher Center Frequency. Postural tremor was more strongly associated with exposure than rest tremor. The finding of increased tremor among the HAVS subjects indicated that tremor might be a part of the clinical picture of a HAVS diagnosis. As with all cross-sectional studies, inferences should be made with caution when drawing conclusions about associations between exposure and possible effects. Future research using longitudinal design is required to validate the findings of the present study.

Can we explain the exposure variability found in hand-arm vibrations when using angle grinders? A round robin laboratory study

OBJECTIVES

To quantify variance components of hand-arm vibration exposure from data collected in a laboratory study of four different angle grinders.

METHODS

Four different angle grinders were sent to seven laboratories for grinding tests by three operators at each laboratory. Vibration in both the throttle and support handles was measured. For one grinder, the experimental set-up was repeated and two measurements were collected for that specific grinder.

RESULTS

At least one-third of the estimated variability is attributable to the wheel and less than one-third to the operator. In repeated experiments, between-occasion, operator and wheel factors explained 4, 29 and 17% of the total variability, respectively.

CONCLUSIONS

Since measured vibrations in the support and throttle handles are significantly differed, measurements should be taken at both locations. Factors influencing vibration variability include the presence/absence of an auto balance unit, wheel and operator, but other factors remain to be elucidated.