Reduced Epidermal Nerve Density Among Hand-Transmitted Vibration-Exposed Workers

Objective: The objective of this study was to evaluate ultrastructural changes of epidermal nerve density (END) in workers exposed to hand-transmitted vibration. Methods: Ten male subjects with occupational exposure to hand-transmitted tools for 46.9 hours weekly for an average of 6.5 years were included in this study. We performed a skin biopsy from the forearms and compared the END with 10 age- and gender- matched healthy control subjects. Results: Nine of the 10 subjects had abnormally low END. The END of the exposed workers was significantly lower than the control group (4.1+ /- 2.8 vs 9.0 +/- 4.3 fibers/mm, P = 0. 005). The difference remained even after one subject with possible undiagnosed diabetes was not included (4.3 +/- 2.9 vs 9.6 +/ - 4.2 fibers /mm, P = 0.005). The reduction of END did not correlate with the abnormality of nerve conduction studies or quantitative sensory testing. Conclusions: The reduction of END suggested the involvement of small-diameter nerve fibers among this population, and such a histologic change might either be independent or precede changes of large myelinated nerve fibers