Incidence rate of Creutzfeldt-Jakob disease in Japan

Background The objective of this study is to clarify the incidence rate of Creutzieldt-Jakob disease (CJD) during the last decade in Japan. Methods A nationwide mail survey was conducted in all hospitals with a minimum bed capacity of 100 and having at least one of three departments: neurology, psychiatry, and neuropathology. The survey required the patient's sex, date of birth, date of diagnosis, diagnostic criteria, medical history and CJD incidence in the family. Results From 493 hospitals throughout the country, 821 patients with CJD were reported from January 1985 through March 1996. The annual incidence rate was 0.49 per million population for males and 0.68 for females. The age-specific incidence rate was highest among those 70-79 years of age, followed by the 60-69, and 50-59 age groups. The incidence and mortality increased during the observed period; however, the incidence rate among younger generations did not rise. Conclusions A nationwide incidence survey of CJD in Japan revealed the incidence and distribution of the disease over the recent decade. It was found that the incidence and mortality rates had increased during the observed period.