Prevalence and mortality of ulcerative colitis and Crohn's disease in Japan.

A descriptive epidemiological study of ulcerative colitis and regional enteritis or Crohn's disease in the general population in Japan was conducted. Mortality rates were based on death certificate records and prevalence rates on the statistics of public aid patients with intractable diseases. Between 1969 and 1985, age-adjusted mortality rates from ulcerative colitis gradually decreased. For regional enteritis, these rates did not change. The prevalence of ulcerative colitis in Japan from April 1, 1984 to March 31, 1985 was 7.85 per 100,000 (6.44 for males, 9.22 for females). The prevalence of Crohn's disease was 1.86 (2.25 for males, 1.48 for females). These figures are one fourth to one fortieth of the rates in Western countries.