Epidemiological Case-Controlstudy to assess the risks of frequency-dependent occupational hand-arm-vibrations

Status:

completed 12/2021

Aims:

Objectives: Hand-arm vibrations are mechanical vibrations caused by hand-guided technical tools, devices or machines. Long-term exposure to hand-arm vibrations can cause pathological changes in the hand-arm-shoulder system. In a multicenter (BG BAU, BGRCI, BGHM and IFA) epidemiological case-control study the possible influence of hand-arm vibration exposure on the risks of musculoskeletal diseases of the hand-arm-shoulder system was investigated.

The following questions should be answered:

1. Is there an association or dose-response relationship between work-related hand-arm vibration and the incidence of musculoskeletal disorders of the hand-arm-shoulder system?
2. Do the different disease patterns differ with regard to the determined dose-effect relationships?
3. What is the significance of the frequency composition of the exposure for the dose-response relationship?

Activities/Methods:

Male cases and controls (1:3, matched by birth years) were recruited for the studies. Cases refer to physician-reported new suspected cases of BK 2103 (with 6 disease pattern: Hand Osteoarthritis (OA), Elbow OA, Shoulder OA, Lunate Osteoarthritis, Scaphoid Peudoarthritis, and Elbow Osteochrondrosis). Controls refer to a random sample of new reportable occupational injuries. A validation study (with radiographic examinations) was performed on approximately 50% of the cases to test the diagnostic accuracy of the SAR. Standardized questionnaires were administered to cases and controls by the supervisors of the respective statutory accident insurance institutions for trade and industry (BG). In addition to leisure activities and comorbidities, the work histories (regarding the use of hand-held technical tools, which can cause hand-arm vibrations) of each study participant were collected in detail. To quantify vibration exposures for each study participant, a database (vibration cadastre) of vibration measurements from over 700 devices was established. This database was used to calculate daily dose (Ahv(8)-typical, Ahw(8)-typical) and long-term dose (Dhv and Dhw) of vibration exposures. Dose-response relationships or frequency-dependent dose-response relationships between vibration exposures and musculoskeletal diseases equivalent to BK 2103 were determined using conditional logistic regressions.

Results:

A total of 209 cases and 614 controls were recruited for the study. The validation study indicates approximately 7.5% misdiagnosis in suspected cases. The average age of the study population is approximately 52 years (22 - 84 yrs). Compared to controls, cases suffer more frequently from gout, arm fracture, hip OA, knee OA, spine OA, and trauma and inflammatory conditions of the finger, elbow, and shoulder joints. The duration of exposure for cases averages approximately 26 (1 - 44) years with a daily dose of Ahv(8)_typical=5.76 m/s² and Ahw(8)_typical=3.36 m/s². For controls, the duration of exposure averaged approximately 25 (0.5 - 49) years with a daily dose of Ahv(8)_typic=4.47 m/s², Ahw(8)_typic=2.46 m/s². After adjusting for relevant confounders (research centers, generalized osteoarthritis, trauma, and inflammatory diseases of the finger, elbow, and shoulder joints), the study analysis shows a statistically significant dose-response relationship between cumulative vibration dose and musculoskeletal diseases equivalent to BK 2103. The dose-response relationships are constant among the different disease patterns and independent of the calculation method of cumulative vibration dose. The frequency-dependent dose-response analyses confirm the assumption that the exposure of hand-arm vibration to the musculoskeletal system occurs predominantly in the frequency range of < 50 Hz.

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