A case-control study of gallstones: a major risk factor for biliary tract cancer.

Because of the strong association between gallstones and biliary tract cancer, we conducted a case-control study of gallstones at Niigata Cancer Center Hospital. Eighty-six cases with gallstones (33 males and 53 females) and 116 hospital controls (56 males and 60 females) were surveyed by means of a self-administered questionnaire. Gallstones were categorized into cholesterol stones (25 cases) and pigment stones (30 cases) based on the appearance of the stones. In multivariate analyses based on an unconditional logistic regression model, the risk of total gallstones was positively associated with a taste for salty food (relative risk (RR) = 2.31, 95% confidence interval (CI): 1.10-4.84), an intake of lettuce and cabbage (RR = 2.98, 95% CI: 1.47-6.06) and a family history of biliary diseases (RR = 5.63, 95% CI: 1.76-17.95), and inversely associated with an intake of salted and dried fish (RR = 0.16, 95% CI: 0.04-0.64). When analyzed by type of stones, cholesterol stones were associated with a taste for oily food (RR = 3.87, 95% CI: 1.36-11.03) and pigment stones were positively associated with professional or administrative occupation (RR = 4.74, 95% CI: 1.35-16.68) and inversely associated with a taste for less greasy food (RR = 0.28, 95% CI: 0.10-0.83). Some of these results are consistent with the results of our previous study on biliary tract cancer.