Epidemiologic aspects of biliary tract cancer in Japan

According to the vital statistics accumulated in Japan from 1958 to 1975, the mortality of biliary tract cancer 1) is low under age 50 and thereafter increases in parallel with age and reaches its peak in the eighth decade; 2) is higher among females than males (especially gallbladder cancer), but cancer of the bile ducts predominates in males; 3) has shown an increasing trend in recent years (1958-75), especially among older persons; and 4) varies geographically. Mortality from this disease is particularly high in the northern parts of Honshu (the main island). Correlation analyses and a factor analysis between food consumption (1964) and the mortality from biliary tract cancer (1972-74) for 46 prefectures in Japan revealed that although expenditures for some foods (dried noodles and pork) are possibly related to the mortality rate of biliary tract cancer, expenditures for others (fat and protein-rich western-type foods) are negatively associated with this cancer. These possible associations need further clarification by more refined epidemiologic and laboratory studies. Possible effects of diagnostic procedures or techniques on secular trends and geographical distribution are also discussed.