Incidence of biliary tract cancer in Los Angeles.

: Incidence data reported for biliary tract cancer in 4 ethnic groups of Los Angeles County are consistent with earlier reports of a similarity between the ethnic-gender distribution of gallbladder cancer and bile lithogenicity, and between that of other biliary cancer and free bilirubin. The female excess of biliary cancer proved to be highest in those ethnic groups with highest average parity, and risk was related to parity correlates such as marital status and religion (Catholic). A migration effect in Spanish-surnamed and other white females was present for both diseases.