OBJECTIVES: To identify risk factors of carcinoma of the extrahepatic biliary tract in men. METHODS: Newly diagnosed and histologically confirmed patients, 35-70 years old, were interviewed between 1995 and 1997 in Denmark, Sweden, France, Germany and Italy. Population controls were frequency-matched by age and region. Adjusted odds ratios and 95%-confidence intervals were estimated by logistic regression. RESULTS: The analysis included 153 patients and 1421 controls. The participation proportion was 71% for patients and 61% for controls. Gallstone disease was corroborated as a risk factor for extrahepatic biliary tract carcinoma in men (odds ratio 2.49; 95% confidence interval 1.32-4.70), particularly for gall bladder tumors (odds ratio 4.68; 95% confidence interval 1.85-11.84). For a body mass index [height (m) divided by squared weight (kg2)] >30 at age 35 years, an excess risk was observed (odds ratio 2.58; 95% confidence interval 1.07-6.23, reference: body mass index 18.5-25) that was even stronger if the body mass index was >30 for the lowest weight in adulthood (odds ratio 4.68; 95% confidence interval 1.13-19.40). Infection of the gall bladder, chronic inflammatory bowel disease, hepatitis or smoking showed no clear association, whereas some increase in risk was suggested for consumption of 40-80 g alcohol per day and more. CONCLUSIONS: Our study corroborates gallstones as a risk indicator in extrahepatic biliary tract carcinoma. Permanent overweight and obesity in adult life was identified as a strong risk factor for extrahepatic biliary tract carcinoma, whereas we did not find any strong lifestyle-associated risk factors. Inconsistent results across studies concerning the association of extrahepatic biliary tract carcinoma with overweight and obesity may be explained by the different approaches to assess this variable.
Keywords: Adult; Aged; Ampulla of Vater; Bile Ducts, Extrahepatic; Biliary Tract Neoplasms; Body Mass Index; Case-Control Studies; Cholelithiasis; Common Bile Duct Neoplasms; Gallbladder Neoplasms; Humans; Life Style; Male; Middle Aged; Obesity; Risk Factors