Epidemiological case-control study for the risk assessment of frequency-dependent work-related hand-arm vibrations

Status:

completed 12/2021

Aims:

The aim of the project is to improve the state of knowledge regarding the correlation between vibration effects on the hand-arm system and musculoskeletal diseases as described in the Occupational Diseases Ordinance (BKV) for occupational disease (BK) No. 2103. In particular, this is intended to close the gap that still exists in the medical bulletin on BK 2103 on the issue of long-term dose and the significance of frequency composition, even after the 2005 revision.

The project, which started in mid-2009, is based on a feasibility study conducted in 2007. For various reasons, such as restructuring of the accident insurance institutions involved and increased sensitivity of the parties concerned to the issue of data protection, the period of case recording had to be extended from the original 2013 to 2020.

During this long period, there were various changes, for example, the "Technical Rule on Noise and Vibration Occupational Health and Safety Ordinance (TRLV)" was issued in 2015, and many new sets of rules were published at the European and international level. The VDI 2057, Sheet 2, which is authoritative in Germany, was also reissued in 2016. The basic concept of the study was retained, but the terms were adapted to those of the new regulations.

The state of knowledge of frequency composition as a cause of different diseases has expanded during the study period (Brammer/Pitts 2012). Exposure data are determined as part of the establishment of an exposure register (see IFA project 4160 "Characteristic values of hand-arm vibration exposure for epidemiological case-control study"). The results are contained in ISO/TR 18570 (2017). However, the additional frequency assessment mentioned there is proposed only with regard to the development of nerve and circulatory disorders. For the clinical pictures investigated in the project, this currently resulted in no changes relevant to the project.

Activities/Methods:

In a multicentre (cooperation of BG BAU, BG RCI, BGHM and IFA) epidemiological case-control study, the possible influence of hand-arm vibration (HAV) exposure on the risks for the development of musculoskeletal diseases of the hand-arm-shoulder system was investigated. The purpose was to clarify the following questions:

1. Is there a 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–response relationships?
3. What is the significance of the frequency composition of the exposure for the dose–response relationship?

Methods: Male cases and controls were recruited for the studies during the period 01/01/2010– 11/30/2020. Cases refer to new suspected cases reported by physicians for BK 2103 (corresponding to six disease patterns: hand osteoarthritis (OA), elbow OA, shoulder OA, lunate necrosis, scaphoid pseudoarthrosis, and elbow osteochondrosis). Controls are drawn from a random sample of new reportable occupational injuries. To test the diagnostic accuracy of a suspected occupational disease, validation (study with radiographic examinations) was performed in approximately 50% of cases. In cases and controls, standardised questionnaire surveys were conducted by the supervisors and occupational disease investigators of the respective institutions for statutory accident insurance and prevention (BGs). In addition to leisure time activities and comorbidities, the work histories regarding the use of hand-held and hand-operated technical tools that can cause hand-arm vibrations of all study participants were collected in detail. In order to quantify vibration exposures for all study participants, a database (vibration register) was established to record vibration measurements from over 700 pieces of equipment. This database was used to calculate the daily dose or lifetime dose of vibration exposures. The dose–response relationships or frequency-dependent dose–response relationships between vibration exposures and musculoskeletal diseases as defined by BK 2103 were determined using conditional logistic regression analysis.

Results:

A total of 209 cases and 614 controls were recruited for the study. The validation study indicates a misdiagnosis rate of approximately 7.7% among cases. Compared to controls, cases are more likely to suffer 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 averages approximately 26 (1–44) years for the cases studied, with a daily dose of a_hv typical(8) (total vibration value) =5.61 m/s² and a_hw typical(8) (frequency-weighted acceleration) =3.34 m/s². For controls, the duration of exposure averaged approximately 25 (0.5 - 49) years with a daily dose of a_hv typical(8) =4.49 m/s² and a_hw typical(8) =2.46 m/s². After adjusting for relevant confounders (study sites, generalised OA, trauma, and inflammatory diseases of the finger, elbow, and shoulder joints), the study analysis showed a statistically significant dose–response relationship between cumulative lifetime HAV dose and musculoskeletal diseases as defined by BK 2103.

According to the estimated dose–response relationships, hand-arm vibration lifetime dose exposures of 142331 m²/s⁴-days for D_hv and 38724 m²/s⁴-days for D_hw lead to a doubling of the risk of musculoskeletal diseases as defined by BK 2103. Similarly, intense hand-arm vibration exposure (a_hw(8) > 2.5 m/s²) of 1596 days (approx. 7.3 years) leads to a doubling of the risk (this is an average value and does not distinguish between individual diseases). According to the courses of the dose–response curves, the 10% and 30% increases of the risk could be determined for the D_hv values of 19571 (95% CI: 12459–45823) m²/s⁴ -days and 53874 (95% CI: 34296–126137) m²/s⁴ -days, respectively, and for the D_hw values of 5325 (95% CI: 3492–11122) m²/s⁴ -days and 14658 (95% CI: 9611–30615) m²/s⁴ -days, respectively. The 10% and 30% increases in the risk in the case of intensive hand-arm vibration exposure (a_hw(8) > 2.5 m/s²) as the trigger value for hand-arm vibration relevant for prevention in accordance with the LärmVibrationsArbSchV (Noise Vibration Ordinance) and the TRLV Vibrations (risk assessment with binding protective measures) are 220 (95% CI: 134–619) days and 604 (95% CI: 368–1702) days, respectively.

The frequency-dependent dose–response analysis confirms the assumption that the impact of hand-arm vibration on the musculoskeletal system occurs predominantly in the frequency range of < 50 Hz. The frequency composition is adequately addressed by the existing frequency assessment. Further information: https://www.dguv.de/ifa/forschung/projektverzeichnis/ff-fp_0297.jsp

Last Update:

12 Sept 2022