Objectives: While there is good evidence from cell-culture and animal studies to indicate that dietary intake impacts breast cancer risk, results of epidemiologic studies have been inconsistent. Additionally, while the etiology of breast cancer in premenopausal versus postmenopausal women may be quite different, most studies have not chosen to focus solely on one group or the other. In this case-control study, we evaluate the associations between red meat, fish, dairy products, and fruits and vegetables, and risk of breast cancer in postmenopausal women.
Methods: A food-frequency questionnaire was completed by 441 women with in-situ or invasive breast cancer and 370 population controls. Cases were identified from the population-based Cancer Surveillance System (CSS) of western Washington and frequency age-matched controls identified by random-digit dialing (RDD). Unconditional logistic regression was used to model the association between each food grouping and breast cancer risk adjusting for age, number of pregnancies, and education.
Results: Red meat intake was significantly associated with an increased breast cancer risk (p for trend = 0.002) and fish (including fried fish) and dairy product intake was inversely associated with breast cancer risk (p for trend = 0.04 and 0.05, respectively). No significant associations were noted betwen fruit or vegetable intake and breast cancer risk.
Conclusions: The findings from this study support the results of several larger cohort studies and contribute to the evidence for the development of dietary recommendations for breast cancer risk reduction specific to postmenopausal women.