DIET AND THE RISK OF SALIVARY-GLAND CANCER

Cancer of the major salivary glands is relatively rare, and little is known about its etiology, The only established risk factors are radiat ion exposure and a prior cancer. The role of diet in the development o f salivary gland tumors has not been addressed previously. The results from a population-based case-control study conducted in the greater S an Francisco-Monterey Bay area examining the association between dieta ry intake and salivary gland cancer risk are presented. Of 199 cases d iagnosed with salivary gland tumors between 1989 and 1993, 150 (75%) w ere interviewed. Nine cases were subsequently excluded based on review of pathology specimens. Of 271 controls identified through random-dig it dialing and the Hearth Care Finance Administration files, 191 (70%) were interviewed. Eight cases and seven controls who over- or underre ported dietary intake were excluded from analysis. Vitamin C intake of >200 mg/day compared with less than or equal to 100 mg/day was associ ated with a 60% decrease in salivary gland cancer risk (odds ratio (OR ) = 0.40, 95% confidence interval (CI) 0.22-0.70), Inverse association s observed for carotene, vitamin E, and fiber from fruits and vegetabl es were diminished when adjusted for vitamin C intake. Fiber from bean sources was associated with a 51% decrease in risk after adjusting fo r vitamin C intake (OR = 0.49, 95% CI 0.26-0.92 for >1.4 g/day compare d with less than or equal to 0.4 g/day), Cholesterol intake was associ ated with elevated risk (OR = 1.67, 95% CI 1.2-2.4 for a 10% increase in calories from cholesterol). These findings suggest that preventive strategies developed for common chronic diseases, such as increased co nsumption of fruits and vegetables and limiting foods high in choleste rol, also may be effective in preventing these rare tumors.