Dietary factors and breast cancer risk in Vaud, Switzerland

Abstract

The relationship between dietary factors and the risk of breast cancer was investigated in a case‐control study conducted in the Canton of Vaud, Switzerland as a pilot phase for a larger cooperative study within the SEARCH Programme of the International Agency for Research on Cancer (Lyon, France). A total of 107 incident, histologically confirmed cases of breast cancer and 318 controls admitted to hospital for acute, nonhormone‐related, gynecological, metabolic, or neoplastic disorders were interviewed. Significant direct trends in risk were observed with total energy intake [relative risk (RR) for highest vs. lowest intake tertile = 1.9] and, after allowance for energy intake, with frequency of consumption of various types of meat (RR = 2.1 for the highest tertile), cheese (RR = 2.7), and alcohol (RR = 2.1). Significant protections, on the order of 40–60% reductions for the highest vs. lowest consumption tertile, were conferred by total green vegetable consumption, selected types of vegetables and fruits (cucumbers, onions, pears), and a summary index of β‐carotene intake (RR = 0.4 for highest consumption tertile). Thus the present study confirmed the existence of an unfavorable dietary pattern for breast cancer risk (characterizedby high‐calorie, selected sources of animal fat and alcohol intake). Moreover, a significant protection could be gained by consuming a diet rich in vegetables and perhaps fruits.