Exposure-response relationship between work-related hand-arm vibration exposure and musculoskeletal disorders of the upper extremities: the German hand-arm vibration study.

Objective. To quantify the exposure-response relationship between hand-arm vibration exposure and the risk of musculoskeletal disorders of the upper extremities (UMSDs), a case-control study was carried out among workers in the construction, mining, metal and woodworking industries. Methods. In total, 209 male cases and 614 controls were recruited. Cases were newly reported patients with UMSDs. Controls were a random sample of persons with compensable occupational injuries. Standardized personal interviews were performed among cases and controls by well-trained safety engineers. In addition to leisure activities and comorbidities, work histories of all participants were collected in detail. To quantify hand-arm vibration exposures, a database of vibration measurements of over 700 power tools was used. This database allows the detailed quantification of vibration exposures over time. A dose-response relationship between hand-arm vibration exposure and UMSDs was quantified by conditional logistic regression analyses. Results and conclusions. After adjusting for relevant confounders, statistically significant exposure-response relationships between cumulative hand-arm vibration exposure and UMSDs were established. A cumulative hand-arm vibration exposure of Dhv (vibration total value in three measuring directions) = 142,300 (95% confidence interval [CI] [90,600-333,200]) m2/s4·day or Dhw (vibration value in the direction along the forearm) = 38,700 (95% CI [25,400-80,900]) m2/s4·day is associated with a doubled risk of UMSDs.