Intake of Fruits, Vegetables, and Soy Foods in Relation to Breast Cancer Risk in Korean Women: A Case-Control Study

Abstract

We conducted a case-control study to examine the relationship between fruit, vegetable, and soy food intake and breast cancer risk in Korean women. Incident cases (n = 359) were identified through cancer biopsies between March 1999 and August 2003 at two university hospitals in Seoul, Korea. Hospital-based controls (n = 708) were selected from patients in the same hospitals during the same period. Subjects were asked by personal interview to indicate their average fruit, vegetable, and soy food intake for a 12-mo period 3 yr prior to the baseline phase. A food intake–frequency questionnaire (98 items) was given by a trained dietitian. Odds ratio (OR) and 95% confidence intervals (CIs) were calculated by unconditional logistic regression after adjustment for confounding factors and total energy intake. There was no association between the intake of total fruits, vegetables, or soy food and breast cancer risk. Increasing consumption of grapes was linked to a significant protective effect against risk of breast cancer (OR = 0.66; 95% CI = 0.41–0.86; P < 0.01). Among the vegetables, reduced risk was observed with high tomato intake (OR = 0.62; 95% CI = 0.38–0.81; P < 0.01). Among soy foods, high consumption of cooked soybeans, including yellow and black soybeans, had an association with reduced breast cancer (OR = 0.67; 95% CI = 0.45–0.91; P < 0.02). Our data suggest that increased intake of some fruits, vegetables, and soy foods may be associated with breast cancer risk reduction in Korean women.

Acknowledgments and Notes

This study was supported by a grant from Hanyang University (November, 2002), Seoul, Korea. We thank nurse Young Hi Ahn (Soonchunhyang University Hospital) for help with field work and Ju Hee Lee for help with statistical computations. Address correspondence to S. S. Lee, Department of Food and Nutrition, College of Human Ecology, Hanyang University, 17 Haengdang-dong, Sungdong-ku, Seoul, 133-791, Korea. Phone: [phone]. FAX: [phone]. E-mail: [email protected]

Notes

^a Values are mean ± SD.

^b First-degree family history of breast cancer.

^c Among women ever pregnant.

^d Among postmenopausal women.

^a ORs, odds ratios; CIs, confidence intervals. Cases = 359; controls = 708.

^b OR was adjusted for age, education, income, age at menarche, parity, age at first live birth, history of breastfeeding, use of hormones (oral contraceptives and hormone replacement), family history of breast cancer in a first-degree relative, frequency of exercise, physical activity, cigarette smoking, and alcohol consumption.

^c Fruits and fruit juices.

^d Citrus fruits generally consumed in Korea (orange, mandarin orange, and grapefruit).

^e Total energy-adjusted intake using residual methods described by Willett and Stampfer (29).

^f Citrus fruit juices generally consumed in Korea (orange, mandarin orange, and grapefruit).

^a ORs, odds ratios; CIs, confidence intervals. Cases = 359; controls = 708.

^b OR was adjusted for age, education, income, age at menarche, parity, age at first live birth, history of breastfeeding, use of hormones (oral contraceptives and hormone replacement), family history of breast cancer in a first-degree relative, frequency of exercise, physical activity, cigarette smoking, and alcohol consumption.

^c Vegetables and vegetable juice.

^d Total energy-adjusted intake using residual methods described by Willett and Stampfer (29).

^e Raw green pepper and sweet green pepper.

^f A type of popular kimchi in Korea made with salted Korean cabbage and sub-ingredients such as garlic, red pepper powder, ginger, leek, and salt-fermented anchovy or salt-fermented shrimp.

^g A kind of kimchi made with salted radish (seasoned cubed radish roots) and sub-ingredients such as baechu kimchi.

^a ORs, odds ratios; CIs, confidence intervals. Cases = 359; controls = 708.

^b OR was adjusted for age, education, income, age at menarche, parity, age at first live birth, history of breastfeeding, use of hormones (oral contraceptives and hormone replacement), family history of breast cancer in a first-degree relative, frequency of exercise, physical activity, cigarette smoking, and alcohol consumption.

^c Soybeans included yellow soybeans and black soybeans.

^d Total energy-adjusted intake using residual methods described by Willett and Stampfer (29).

a:Mean ± SD.