Diet and squamous-cell cancer of the oesophagus: a French multicentre case-control study

An increasing number of reports suggest that diet has an impact on oesophageal cancer risk in Western countries, where alcohol and tobacco are held to be the major determinants of the risk. The aim of our study was to identify dietary factors influencing the risk of oesophageal cancer in France and to determine whether certain of these could explain some of the geographical variations. We conducted a multicentre case-control study in 3 regions expected to have different diet and drinking habits (Normandy, Burgundy and Midi Pyrénées). Two hundred eight cases and 399 controls, all males, were interviewed about their eating, drinking and smoking habits. After proper adjustment for drinking and smoking, high consumption of butter and low consumption of fresh fish, vegetables and fruits were associated strongly and independently with an increase in oesophageal-cancer risk. Consistently, cholesterol appeared as a risk factor and vitamin E, vitamin D and phosphorus as independent protective factors. The protective effect of citrus and other fresh fruits (vitamin C) was confined strictly to heavy drinkers. Our findings suggest that more than one-third of the high incidence of oesophageal cancer in northwest France could be explained by the local excess in butter consumption, whereas geographical variations in consumption of dietary protective factors could explain no more than 10% of it. Overall, a large proportion (57%) of the excess incidence of oesophageal cancer in northwest France could be explained by local dietary habits, e.g., drinking hot Calvados liquor and excessive consumption of butter.