A vegetable-fruit-soy dietary pattern protects against breast cancer among postmenopausal Singapore Chinese women.
BACKGROUND
Prospective epidemiologic studies in Asian populations consistently show that soy is protective against breast cancer.


OBJECTIVE
The objective was to prospectively evaluate whether the protective effect of soy is due to soy isoflavones alone or to their combination with other beneficial dietary factors in an Asian population.


METHODS
Using principal components analysis, we previously identified a "meat-dim sum" pattern characterized by meat, starch, and dim sum items and a "vegetable-fruit-soy" pattern characterized by cruciferous vegetables, fruit, and tofu items in a population-based cohort of Singapore Chinese initiated between 1993 and 1998. Component scores representing intakes of each pattern were used in multivariable Cox regression models to analyze the relation between diet at baseline and breast cancer incidence.


RESULTS
As of 31 December 2005, 629 incident breast cancer cases had been diagnosed among the 34,028 women. With greater intake of the vegetable-fruit-soy dietary pattern, we observed a dose-dependent trend (P < 0.01) for decreasing breast cancer risk among postmenopausal women [hazard ratio (HR): 0.70; 95% CI: 0.51, 0.95 for the fourth compared with first quartile]. A stronger association for the vegetable-fruit-soy pattern was observed among postmenopausal women with > or =5 y of follow-up (HR: 0.57; 95% CI: 0.36, 0.88; P for trend <0.01). No trend was observed for a greater intake of the meat-dim sum dietary pattern and increased breast cancer risk.


CONCLUSIONS
Our findings support the hypothesis that a diet characterized by vegetables, fruit, and soy has an early-acting protective effect on breast carcinogenesis.
Butler
Lesley M
LM
Department of Environmental, Colorado State University, Fort Collins, CO 80523-1681, USA. lesley.butler@colostate.edu
Wu
Anna H
AH
Wang
Renwei
R
Koh
Woon-Puay
WP
Yuan
Jian-Min
JM
Yu
Mimi C
MC
D000368:Aged; D000972:Antineoplastic Agents, Phytogenic / Q000627:therapeutic use*; D044466:Asian People; D001943:Breast Neoplasms / Q000453:epidemiology / Q000517:prevention & control*; D004032:Diet; D004305:Dose-Response Relationship, Drug; D005260:Female; D005638:Fruit; D006801:Humans; D015994:Incidence; D007529:Isoflavones / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010936:Plant Extracts; D017698:Postmenopause; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012846:Singapore / Q000453:epidemiology; D045730:Soy Foods; D013025:Glycine max / Q000737:chemistry; D016896:Treatment Outcome; D014675:Vegetables
D000972:Antineoplastic Agents, Phytogenic; D007529:Isoflavones; D010936:Plant Extracts