INTAKE OF SELECTED MICRONUTRIENTS AND THE RISK OF BREAST-CANCER

To investigate the relation between selected micronutrients and breast cancer risk, we conducted a case control study of breast cancer betwe en June 1991 and April 1994 in 6 Italian areas. The study included 256 9 women admitted to the major teaching and general hospitals of the st udy areas with histologically confirmed incident breast cancer and 258 8 control women with no history of cancer, who were admitted to hospit als in the same catchment areas for acute, non-neoplastic, nongynecolo gical conditions unrelated to hormonal or digestive tract diseases or to long-term modifications of the diet. Dietary habits, including alco holic beverage consumption, were investigated using a validated food f requency questionnaire, including 78 foods or food groups, several typ es of alcoholic beverages, some ''fat intake pattern'' questions and s ome open sections for foods consumed frequently by the subject and not reported in the questionnaire. To control for potential confounding f actors, several multiple logistic regression models were used. When ma jor correlates, energy intake and the mutual confounding effect of the various micronutrients were taken into account, beta-carotene, vitami n E and calcium showed a significant inverse association with breast c ancer risk. The estimated odds ratios of the 5th quintile compared to the lowest one were 0.84 for beta-carotene, 0.75 for vitamin E and 0.8 1 for calcium. No significant association emerged for retinol, vitamin C, thiamin, riboflavin, iron and potassium. Our results suggest that a diet rich in several micronutrients, particularly beta-carotene, vit amin E and calcium, may be protective against breast cancer. (C) 1996 Wiley-Liss, Inc.