title: Intake of carrots, spinach, and supplements containing vitamin A in relation to risk of breast cancer.
abstract: Intake of fruits, vegetables, vitamin A, and related compounds are associated with a decreased risk of breast cancer in some studies, but additional data are needed. To estimate intake of beta-carotene and vitamin A, the authors included nine questions on food and supplement use in a population-based case-control study of breast cancer risk conducted in Maine, Massachusetts, New Hampshire, and Wisconsin in 1988-1991. Multivariate-adjusted models were fit to data for 3543 cases and 9406 controls. Eating carrots or spinach more than twice weekly, compared with no intake, was associated with an odds ratio of 0.56 (95% confidence interval 0.34-0.91). Estimated intake of preformed vitamin A from all evaluated foods and supplements showed no trend or monotonic decrease in risk across categories of intake. These data do not allow us to distinguish among several potential explanations for the protective association observed between intake of carrots and spinach and risk of breast cancer. The findings are, however, consistent with a diet rich in these foods having a modest protective effect.
authors.affiliation: Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Longnecker
authors.forename: P A
authors.initials: PA
authors.lastname: Newcomb
authors.forename: R
authors.initials: R
authors.lastname: Mittendorf
authors.forename: E R
authors.initials: ER
authors.lastname: Greenberg
authors.forename: W C
authors.initials: WC
authors.lastname: Willett
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage*; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000517:prevention & control; D016022:Case-Control Studies; D018552:Daucus carota; D004034:Diet Surveys; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D018724:Spinacia oleracea; D014801:Vitamin A / Q000008:administration & dosage*; D019207:beta Carotene / Q000008:administration & dosage*
chemical_list: D000975:Antioxidants; D019207:beta Carotene; D014801:Vitamin A