A longitudinal study of neck and upper limb musculoskeletal disorders and alternative measures of vibration exposure.
OBJECTIVE
To investigate the exposure-response relationships between alternative frequency weightings of hand-transmitted vibration (HTV) and neck and upper limb musculoskeletal disorders (MSDs) in a cohort of HTV workers.


METHODS
In a three-year longitudinal study, the occurrence of neck and upper limb MSDs was investigated in 249 HTV workers and 138 control men. In the HTV workers, MSDs were related to measures of daily vibration exposure expressed in terms of 8-h energy-equivalent frequency-weighted acceleration magnitude [A(8)]. To calculate A(8), the acceleration magnitudes of vibration were weighted by means of four alternative frequency weightings of HTV. The associations between MSDs, individual characteristics, physical work load other than vibration, and psychological strain were also investigated.


RESULTS
The occurrence of upper limb MSDs was greater in the HTV workers than in the controls. After adjustment for potential confounders, the occurrence of elbow/forearm and wrist/hand MSDs increased with the increase in vibration exposure. A measure of model selection did not reveal any substantial difference in the performance of the alternative frequency weightings of HTV for the prediction of neck and upper limb MSDs. In the study population, age, hard physical work load, and poor psychological well-being were associated with both neck and upper limb MSDs.


CONCLUSIONS
In this study, there was evidence for significant exposure-response relationships between HTV exposure and MSDs in the distal sites of the upper limbs. There were no differences in the prediction of neck and upper limb MSDs between measures of daily vibration exposure calculated with alternative frequency weightings of acceleration magnitude.
Clinical Unit of Occupational Medicine, Department of Medical Sciences, University of Trieste, Centro Tumori, Via della Pietà 19, 34129, Trieste, Italy. bovenzi@units.it.
Massimo
M
Bovenzi
Clinical Unit of Occupational Medicine, Department of Medical Sciences, University of Trieste, Centro Tumori, Via della Pietà 19, 34129, Trieste, Italy.
Andrea
A
Prodi
Clinical Unit of Occupational Medicine, Department of Medical Sciences, University of Trieste, Centro Tumori, Via della Pietà 19, 34129, Trieste, Italy.
Marcella
M
Mauro
D000328:Adult; D016022:Case-Control Studies; D019652:Extraction and Processing Industry; D016468:Forestry; D053421:Hand-Arm Vibration Syndrome / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009140:Musculoskeletal Diseases / Q000453:epidemiology* / Q000209:etiology; D009333:Neck; D009784:Occupational Diseases / Q000453:epidemiology* / Q000209:etiology; D016273:Occupational Exposure / Q000009:adverse effects / Q000032:analysis*; D011237:Predictive Value of Tests; D015995:Prevalence; D034941:Upper Extremity; D014732:Vibration / Q000009:adverse effects
Frequency weightings; Hand-transmitted vibration; Neck and upper limb musculoskeletal disorders; Physical work load; Prospective cohort study; Psychological strain