Incidence of Bell's palsy

The annual incidence of Bell's palsy in three consecutive years--1984, 1985, and 1986--was investigated in Ehime Prefecture in Japan, which has a population of 1,530,000. The number of new patients with Bell's palsy was solicited from 1,377 medical institutions and their referral hospitals. The clinical records of the 15 main hospitals were examined personally by the author to confirm the exact numbers. Special care was taken to ensure minimal error in the present epidemiologic investigation. The annual incidence of Bell's palsy per 100,000 population was found to be 30, and no annual variation was noted. The ratio of male to female patients was 48:52 in all cases. There was no geographic difference in incidence.