Summary

Background: Squamous cell oesophageal cancer is one of the few neoplasms inversely related to body mass index (BMI). However, it is not clear whether this is due to cancer-related weight loss or to other correlates of leanness. Patients and methods: 395 incident, histologically confirmed cases of squamous cell oesophageal cancer and 1,066 controls, admitted for acute, non-neoplastic diseases, in Italy and Swit-zerland. Odds ratios (ORs) were derived from multiple logistic regression, including terms for education, tobacco, alcohol, non-alcohol energy, fruit and vegetable intake. Results: The ORs for the lowest vs. the highest quartile of BMI in the year before diagnosis were 2.0 in men, 1.6 in women, and 1.9 (95 % confidence interval: 1.3-2.9) in both sexes combined. The association with leanness was stronger in heavy smokers, but was not accounted for by smoking and drinking, nor by differences in diet. Weight change in the decade prior to diagnosis showed no linear association with risk. However, cases were not leaner than controls at age 30 (OR = 0.6 for the lowest BMI quartile) and 50 (OR = 1.1). Conclusions: Leanness appears to be an indicator of squa-mous cell oesophageal carcinogenesis. However, low BMI in the distant past was unrelated to oesophageal cancer risk. Key words: body mass index, drinking, oral cancer, oesopha-geal cancer, smokin