Diet and biliary tract cancer risk in Shanghai, China

Trends in biliary tract cancer incidence rates have increased in Shanghai, China. These trends have coincided with economic and developmental growth, as well as a shift in dietary patterns to a more Westernized diet. To examine the effect of dietary changes on incident disease, we evaluated associations between diet and biliary tract cancers amongst men and women from a population-based case-control study in Shanghai, China. Biliary tract cancer cases were recruited from 42 collaborating hospitals in urban Shanghai, and population-based controls were randomly selected from the Shanghai Household Registry. Food frequency questionnaire data were available for 225 gallbladder, 190 extrahepatic bile duct, and 68 ampulla of Vater cancer cases. A total of 39 food groups were created and examined for associations with biliary tract cancer. Interestingly, only four food groups demonstrated a suggested association with gallbladder, extrahepatic bile duct, or ampulla of Vater cancers. The allium food group, consisting of onions, garlic, and shallots showed an inverse association with gallbladder cancer (OR: 0.81, 95% CI: 0.68-0.97). Similar trends were seen in the food group containing seaweed and kelp (OR: 0.79, 95% CI: 0.67-0.96). In contrast, both preserved vegetables and salted meats food groups showed positive associations with gallbladder cancer (OR:1.27, 95% CI: 1.06-1.52; OR: 1.18, 95% CI: 1.02-1.37, respectively). Each of these four food groups showed similar trends for extrahepatic bile duct and ampulla of Vater cancers. The results of our analysis suggest intake of foods with greater anti-inflammatory properties may play a role in decreasing the risk of biliary tract cancers. Future studies should be done to better understand effects of cultural changes on diet, and to further examine the impact diet and inflammation have on biliary tract cancer incidence.