Influence of food groups and food diversity on breast cancer risk in Italy.

Although debate on breast cancer and diet has been concentrated on nutrients, assessment of the role of specific foods and food groups and variety of food intake retains a considerable importance. To further elucidate the role of dietary habits, 2,569 women with incident breast cancer (median age 55 years) and 2,588 control women (median age 56 years), hospitalised with acute non-neoplastic diseases, were interviewed between 1991 and 1994 in 6 different Italian areas. The validated food frequency questionnaire included 79 food items and recipes, which were grouped into 18 food groups (5 for "diversity" analyses purpose). After allowance for non-dietary confounding factors and total energy intake, significant trends of increasing breast cancer risk with increasing intake emerged for the following food groups: bread and cereal dishes, pork and processed meats, and sugar and candies. Conversely, high intake of milk, poultry, fish, raw vegetables, potatoes and coffee and tea seemed to exert a protection against the development of breast cancer. Intake of soups, eggs, other meats, cheese, cooked vegetables, citrus fruits, other fruits and cake and desserts were not significantly related to breast cancer risk. The variety of vegetable types consumed weekly seemed to have a beneficial effect beyond the advantage of high vegetable intake per se.