Dietary patterns and risk of breast cancer

A factor analysis of food and nutrient intakes

Abstract

Introduction: diet is considered a determining factor in breast carcinogenesis. If compared to a traditional epidemiological analysis of isolated food and nutrient intakes, the factor analysis creates patterns of associated elements, what is also useful for international comparisons.
Objective: to explore the dietary risk factors of breast cancer by means of a simultaneous factor analysis in food and nutrient intakes.
Method: we conducted a case control study where 442 cases of breast cancer and 442 controls were matched by age, residence and urban/rural status. All patients belonged to the lower socioeconomic status (low average of education and income). Controls did not evidence conditions associated to smoking or the consumption of alcohol, and they had not modified their diets either. A factor analysis (main components) was conducted among controls for individual food and nutrients on the basis of a food questionnaire of 64 items, which had already been used in several previous control case studies.
Results: the factor analysis made with food kept the following factors: western, traditional, total fruits, cautious and processed meats. This analysis using nutrients kept the animal base, starch/dairy products, fruit base and carotenoids. While the western pattern showed an increased significant risk of breast cancer (OR= 2.15), the prudent pattern was inversely and significantly associated (OR= 0.67). In nutrient patterns the animal base factor was directly associated to breast cancer, whereas the carotenoid factor was inversely associated to it. There were association differences depending on the menopausal status.
Conclusions: factor analysis showed the potential role of dietary elements in foods and nutrients, both as risk and protective factors, in the etiology of breast cancer.