Dietary sugar intake in the aetiology of biliary tract cancer.

Although gallstones and obesity are important risk factors for biliary tract cancer, the relation between diet and this type of cancer has not been studied in detail. Between 1984 and 1988 we conducted a case-control study of 111 cases of biliary tract cancer and 480 controls from the general population. Food intake was assessed by means of a semiquantitative food frequency questionnaire. Estimates of the total energy intake and the intake of macronutrients were obtained from the patients and controls themselves (direct respondents) or from relatives (indirect respondents). The major finding is that the risk associated with the intake of sugars (i.e. the combined intake of monosaccharides and disaccharides), independent of other sources of energy, is more than doubled for indirect respondents and for both respondent groups combined. A biological explanation for the fact that the intake of sugars may be a risk factor for biliary tract cancer might be based on the relationships between sugar, blood lipids and gallstone formation.