Intake of dietary fat and vitamin in relation to breast cancer risk in Korean women: a case-control study.

To investigate association between breast cancer risk and nutrients intake in Korean women, a case-control study was carried out, at Seoul, Korea. Incident cases (n=224) were identified through the cancer biopsy between February 1999 and December 2000 at two University hospitals in Seoul. Hospital-based controls (n=250) were selected from patients in the same hospitals, during the same periods. Food intake was investigated semiquantitative frequency questionnaire (98 items) by trained dietitian. Subjects were asked to indicate the average food intake and vitamin supplement for a 12 months period of 3-yr prior to the baseline phase. In investigation of vitamin supplement use, subjects were asked the average frequency of use, duration, dose and the brand name of vitamin supplement (multivitamins, vitamin A, vitamin C and vitamin E). And nutrients were calorie adjusted by the residuals method. In this study, higher breast cancer risk incidence was not observed with higher intake of total fat and saturated fatty acids, however statistically significant trends with breast cancer incidence for total saturated fatty acids were found (ptrend=0.0458). In analyses of vitamins, beta-carotene and vitamin C were significantly associated with decreasing risk of breast cancer. In analyses, results from dietary plus supplement of vitamin was not associated with breast cancer risk in this study. In conclusion, our findings suggest that antioxidant vitamins such as beta-carotene and vitamin C intake could lower the breast cancer risk in Korean women.