Objective: To determine if gallstone disease is associated with an increased risk for malignancy and higher total mortality in Pima Indians.
Design: Inception cohort.
Setting: American Indian community.
Participants: Age- and sex-stratified random population-based sample.
Measurements: Between 1966 and 1969, an age- and sex-stratified random sample of Pima Indians from the Gila River Indian Community in Arizona was examined to identify evidence of gallstone disease defined as either gallstones (oral cholecystography) or previous cholecystectomy. During 20 years of follow-up, deaths were recorded and underlying causes of death, according to death certificates, were determined.
Results: Among 383 persons with known gallbladder status, 186 (49%) died: 133 among the 222 persons with gallstone disease and 53 among the 161 without. The overall death rate was higher in persons with gallstone disease than in those with normal gallbladders. The age-and sex-adjusted death rate ratio was 1.9 (95% CI, 1.3 to 2.7). Furthermore, the death rate attributed to malignancies was 6.6 times (CI, 1.3 to 33.1) as high in persons with gallstone disease as in those with normal gallbladders. Of the 20 fatal malignancies in persons with gallstone disease, 11 occurred in the digestive tract, of which six involved the gallbladder or bile ducts.
Conclusions: Increased cancer mortality and total mortality were found in Pima Indians with gallstone disease. Although plausible explanations exist for the increased cancer mortality, the increased death rates due to other causes are unexplained. Whether cholecystectomy would change this risk is unknown.