Risk of frostbite in vibration-induced white finger cases.

The rate of frostbite was examined with questionnaires filled by 1095 reindeer herders frequently exposed to cold, in particular in driving snowmobiles in the winter. Altogether 443 frostbite injuries, most (72%) of them on the face, had occurred during the last two years, especially when driving a snowmobile. The prevalence of vibration-induced white finger (VWF) was 22%. In this VWF group (N = 243) the cumulative incidence rate in two years of frostbite injuries on the extremities was 27% and in the non-VWF group (N = 852) only 5%. There was no difference in the incidence of frostbite on the face and ear lobe. The amount of frostbitten subjects, with respect to both frostbite on the extremities and head, was significantly associated with the use of snowmobiles during the last two years. According to the results VWF cases have an increased risk of frostbite in the extremities on a cold environment.