The sixth nationwide epidemiological survey of chronic pancreatitis in Japan

Objectives: A nationwide survey was conducted to clarify the epidemiological features of patients with chronic pancreatitis (CP) in Japan. Methods: Two sequential surveys were conducted. In the first survey, both the prevalence and incidence of CP in Japan in 2007 were estimated by a questionnaire, which was mailed to 3027 randomly chosen Japanese facilities. In the second survey, the second questionnaire was then mailed to 1110 facilities selected by the first survey to clarify the clinicoepidemiological features of the patients. Results: The estimated annual prevalence of CP was 36.9 per 100,000; 53.2 in males and 21.2 in females. The estimated annual incidence was 11.9 per 100,000. The prevalence and the incidence of CP gradually increased in Japan as compared to former surveys. The sex ratio (male/female) of definitive and probable CP patientswas 4.5, with a mean age of 59.4 years; 59.2 years in males and 60.2 years in females. Alcoholic (69.7%) was most the common and idiopathic (21.0%) was the second most common cause of CP. The proportion of alcoholic CP increased as compared to the 55.5% found in 1994. The clinical features of overall Japanese patients with CP were: abdominal pain (60.6%), malabsorbtion (12.2%), diabetes mellitus (39.7%) and pancreatolithiasis (75.7%). Alcoholic patients were characterized by high morbidity as compared to nonalcoholic patients: abdominal pain (alcoholic 65.0% vs nonalcoholic 53.0%, p < 0.0001), diabetes mellitus (44.8% vs 31.4%, p < 0.0001) and pancreatolithiasis (84.0% vs 60.8%, p < 0.0001). Conclusion: The prevalence and the incidence of CP, especially alcoholic CP, have been increasing in Japan.