Objective: The association between body mass index (BMI) and the risk of oral cavity cancer, suggested by the few available studies, is controversial because of weight loss preceding cancer diagnosis and possible confounding by tobacco and alcohol consumption. The aim of this study was to evaluate in France, a high-incidence country, the association between the risk of oral cavity cancer and body mass index at interview, 2 years before the interview and at age 30, as well as BMI change.
Methods: We used data from a population-based case-control study, the Investigation of occupational and environmental CAuses of REspiratory cancers study, with personal interviews and standardized questionnaires including 689 cases of oral cavity squamous cell carcinoma and 3,481 controls. Odds ratios (ORs) and 95% confidence intervals (95% CI) were estimated by unconditional logistic regression and were adjusted for gender, age, area of residence, education, tobacco smoking, and alcohol drinking.
Results: ORs were increased in underweight subjects at interview (OR 6.25, 95% CI 3.74-10.45). No association with underweight 2 years before the interview and at age 30 was found. Overweight and obesity at interview, 2 years before the interview and at age 30 were associated with decreased ORs (ranging from 0.13 to 0.60). BMI gain greater than 5% between age 30 and 2 years before the interview was inversely associated with oral cavity cancer (OR 0.42, 95% CI 0.33-0.54). These associations were stronger in men, and in smokers and drinkers.
Conclusion: These results add further support to the existence of a reduced risk of oral cavity cancer among overweight and obese people or among people who increased their BMI in adulthood. The underlying mechanisms remain to be clarified.