Nutritional factors in the etiology of brain tumors: potential role of nitrosamines, fat, and cholesterol.

Several possible risk factors for brain tumors have been suggested in the past, including N-nitroso compounds, but with the exception of ionizing radiation, none has been consistently confirmed. The present study was aimed at assessing the influence of nutritional factors, including N-nitroso compounds, in the etiology of brain tumors, specifically gliomas and meningiomas. One hundred and thirty-nine cases with confirmed brain tumors diagnosed between 1987 and 1991 in central Israel and 278 controls matched according to age, sex, and ethnic origin were interviewed. Nutritional data were obtained using a semiquantitative food frequency approach. A significant positive association for both types of brain tumors was found with high protein intake (odds ratio (OR) = 1.94, 95% confidence interval (CI) 1.03-3.63), while intake of sodium was inversely related to both types of brain tumors (OR = 0.52, 95% CI 0.31-0.87). Increased consumption of total fat and cholesterol was inversely related to gliomas (high intake of fat: OR = 0.45, 95% CI 0.20-1.07; high intake of cholesterol: OR = 0.38, 95% CI 0.14-1.01). However, neither fat intake nor cholesterol intake was significantly related to the risk of meningiomas. Although N-nitroso compounds were not found to be directly associated with brain tumors, the data suggested the presence of an interaction between the effects of N-nitroso compounds and protein intake and between N-nitroso compounds and cholesterol intake. The data suggest that dietary factors may play an important, though yet undefined, role in the development of brain tumors.