Vibration of hand-held tools is considered to induce disorders in the peripheral circulation, peripheral nerve and organs, muscles, bones and joints (vibration syndrome). Above all, Raynaud's phenomenon is known as a prominent sign of vibration syndrome.
This paper describes the findings obtained from the observation of the skin of the hands exposed to vibration and evaluates the relation between Raynaud's phenomenon and cutaneous changes. A total of 124 chain-saw workers in a forestry company in Gifu Prefecture were investigated in connection with compulsory health examination. In medical occupational interview, every worker was asked whether he had any experience of Raynaud's phenomenon or not. Moreover, the following symptoms of the skin and nails of the hand (s) were examined: 1. sclerodactylia, 2. pitting scar, 3. edema, 4. erythema around the nail, and 5. elongation and bleeding of proximal nailfolds and cuticles. To determine whether vibration induces the above mentioned cutaneous changes, the relation between the prevalence of the changes and the duration of exposure to vibration was assessed. The workers were classified into four groups by duration of exposure to vibration (in intervals of 10 years). The evaluation was made by comparing the prevalence of cutaneous changes between the workers with Raynaud's phenomenon and those without it. Subjects were restricted in age from 40 to 59 years.
There was a significant relationship between age and duration of exposure (p<0.001). The prevalence of Raynaud's phenomenon was significantly high among the workers in the fifties (15.8%). The prevalence of Raynaud's phenomenon was significantly increased in workers with longer exposure. The prevalence of Raynaud's phenomenon was 6.9% in workers in the forties. Though the prevalence of sclerodactylia and elongation and bleeding of proximal nailfolds and cuticles was higher in workers in the fifties than those in the forties, (1. 34.7% in the 50 s, 24.1% in the 40 s 5. 27.4% in the 50 s, 17.2% in the 40 s), no relation could be demonstrated between the duration of exposure and the prevalence of cutaneous changes. There were no significant differences in the prevalence of cutaneous changes between the workers with Raynaud's phenomenon and those without Raynaud's phenomenon.