Beta-carotene intake and risk of postmenopausal breast cancer

We assessed the relation between beta-carotene consumption at various times in life and breast cancer risk by conducting a case-control study nested w ithin a population-based cohort of women screened for breast cancer in Swed en. We conducted a telephone interview with 273 incident breast cancer case s and 371 controls about their diet at various ages throughout their Lifeti me. Controls were frequency matched to cases on age, month and year of mamm ography, and county of residence. We used unconditional logistic regression to measure the association between beta carotene intake and breast cancer risk while adjusting for total energy intake, recency of intake, and the ma tching variables. Women were at lower risk with increasing levers of report ed intake of beta-carotene. This pattern of association between breast canc er and beta-carotene intake was similar at various times before screening. These findings indicate that although diets high in beta-carotene may be as sociated with lower breast cancer risk, there does not seem to be evidence of a critical time period during which such diets are more relevant.