Dietary patterns related to glycemic index and load and risk of premenopausal and postmenopausal breast cancer in the Western New York Exposure and Breast Cancer Study.
BACKGROUND
Reduced rank regression (RRR) has been used to identify dietary patterns that predict variation in a selected risk factor and may be useful in describing dietary exposures associated with glycemic index (GI) and glycemic load (GL).


OBJECTIVE
To estimate breast cancer risk, we compared the relative utility of RRR-derived dietary patterns predictive of GI and GL with those of simple GI and GL.


METHODS
RRR was used to identify dietary patterns predicting GI and GL from food-frequency data obtained in the Western New York Exposure and Breast Cancer Study (1166 cases, 2105 controls). Odds ratios (ORs) and 95% CIs were estimated with unconditional logistic regression, adjusted for energy and nondietary breast cancer risk factors.


RESULTS
Sweets, refined grains, and salty snacks explained 34% of the variance in GI and 68% of the variance in GL. In general, breast cancer risks were not associated with GI, GL, or dietary pattern score. However, we observed a significant reduction in postmenopausal breast cancer risk with GI and GL pattern scores combined (OR: 0.68; 95% CI: 0.50, 0.93), especially in women with a body mass index (in kg/m(2)) >or=25 (OR: 0.64; 95% CI: 0.44, 0.93). Conversely, in premenopausal women, increased risks were associated with high GL pattern scores only for women with a body mass index >or=25 (OR: 2.21; 95% CI: 1.04, 4.69).


CONCLUSIONS
Although RRR may be useful in studies of diet and disease, our results suggest that RRR dietary patterns based on GI and GL provide similar information regarding the association between breast cancer, GI, and GL.
McCann
Susan E
SE
Department of Cancer Prevention and Control, Roswell Park Cancer Institute, Buffalo, NY 14263, USA. susan.mccann@roswellpark.org
McCann
William E
WE
Hong
Chi-Chen
CC
Marshall
James R
JR
Edge
Stephen B
SB
Trevisan
Maurizio
M
Muti
Paola
P
Freudenheim
Jo L
JL
D015992:Body Mass Index; D001943:Breast Neoplasms / Q000453:epidemiology*; D004032:Diet; D005247:Feeding Behavior; D005260:Female; D038321:Glycemic Index; D006304:Health Status; D006801:Humans; D008019:Life Style; D008875:Middle Aged; D009518:New York / Q000453:epidemiology; D016017:Odds Ratio; D017698:Postmenopause; D017697:Premenopause; D012044:Regression Analysis; D018570:Risk Assessment