Background: Many studies of fruit and vegetable consumption showed inverse associations with breast cancer risk, suggesting the potential importance of carotenoids (and other phytochemicals) contained in these foods. To date, however, only one prospective cohort study has examined dietary carotenoids other than beta-carotene in relation to breast cancer risk.
Objective: Our aim was to examine the relations between dietary intakes of beta-carotene, alpha-carotene, beta-cryptoxanthin, lycopene, and lutein + zeaxanthin and breast cancer risk in a large cohort study of Canadian women.
Design: A case-cohort analysis was undertaken in a cohort of 56 837 women who were enrolled in the Canadian National Breast Screening Study and who completed a self-administered dietary questionnaire. During follow-up to the end of 1993 a total of 1589 women were diagnosed with biopsy-confirmed incident breast cancer. For comparison, a subcohort of 5681 women was randomly selected. After exclusions for various reasons, the analyses were based on 1452 cases and 5239 noncases.
Results: We found no clear association between intakes of any of the studied carotenoids and breast cancer risk in the study population as a whole or in subgroups defined by smoking status; relative body weight (assessed by body mass index); intakes of total fat, energy, alcohol, or folic acid; family history of breast cancer; or menopausal status.
Conclusions: Our data do not support any association between dietary intakes of the studied carotenoids and breast cancer risk. However, prospective cohort studies of carotenoids in relation to breast cancer are scarce and further studies are warranted.