A study of the hand-arm vibration syndrome in Okinawa, a subtropical area of Japan.

The purpose of this study was to understand the peculiarity of the development of Hand-Arm Vibration Syndrome (HAVS) in a subtropical area of Japan. We analyzed the medical records of 21 subjects reported by the Okinawa Labor Bureau, and tried to determine whether the warm environment has any effect on the severity of HAVS. The mean operating time of vibration tools for all the subjects was over 10,000 hrs. Almost all the subjects from Okinawa had been working only in Okinawa. The presence of Vibration Induced White Fingers (VWF) was markedly smaller in the subjects from Okinawa as compared to those from other prefectures. The results of Cold Water Immersion Tests were similar for all subjects. Ten minutes after the Cold Water Immersion Test, the mean finger skin temperature was about 19 degrees C in all subjects. These findings suggest that not only the operating time of vibration tools but also the warm environment might have an effect on the severity of HAVS. However, the number of subjects in our study was very small. There is the need therefore for further investigations with a larger number of subjects.