Symptoms of vibration syndrome and radiographic findings in the wrists of lumberjacks.

In a cross sectional study 279 lumberjacks exposed to chain saw vibration and a reference group of 178 peat bog workers were examined. The mean ages of the two groups were 34.6 and 33.1 years, respectively. The lumberjacks' mean duration of exposure to vibration was 10.4 years. The study consisted of a questionnaire and a clinical examination, including radiographs of the wrists. The prevalence of reported white finger symptoms was 18% for the lumberjacks and 3% for the referents, whereas that of numbness in the upper extremities was 51% and 22%, respectively. Among lumberjacks the occurrence of white finger symptoms increased significantly with the duration of exposure to vibration but was not associated with age or smoking. The prevalence of the numbing of the upper extremities increased linearly with age in both groups, but it was not associated with duration of exposure after adjustment for age. Among lumberjacks there was a significant association between the numbing symptom and the white finger symptom, but not among the referents. A high prevalence of numbing in the upper extremities among the lumberjacks could be at least partly explained by occupational factors other than vibration--work posture, for example. Radiographically, cysts were found in the wrist bones of 8-9% of both groups. The exposure to chain saw vibration no longer seems to be a determinant in the development of vacuoles in the carpal bones.