Isoflavones from phytoestrogens and gastric cancer risk: a nested case-control study within the Korean Multicenter Cancer Cohort.
BACKGROUND
The role of soybean products in gastric cancer risk is not clear in epidemiologic studies due to measurement error from dietary intake questionnaires and due to different degrees of bias according to study design. To examine the association between soybean products and gastric cancer risk, we measured phytoestrogen biological markers in a nested case-control study.


METHODS
The study population was composed of 131 cases and 393 matched controls within the Korean Multicenter Cancer Cohort. The concentrations of the four biomarkers in the plasma samples were measured using time-resolved fluoroimmunoassay. Conditional and unconditional logistic regression models were used to compute the odds ratio (OR) and 95% confidence intervals (CI).


RESULTS
Median plasma concentrations of genistein (229 nmol/L for controls, 181.8 nmol/L for cases; P=0.07) and daidzein (131.2 nmol/L for controls, 80.5 nmol/L for cases; P=0.04) in cases were lower than in controls, whereas equol concentrations were similar. Compared with the reference group, gastric cancer risk decreased in the highest groups for genistein (OR, 0.54; 95% CI, 0.31-0.93) and daidzein (OR, 0.21; 95% CI, 0.08-0.58). Higher equol concentrations were associated with a decreased risk for gastric cancer (OR, 0.50; 95% CI, 0.27-0.90). The combination of the highest concentrations for each isoflavone category was associated with a 0.09-fold decreased risk for gastric cancer compared with the combination of the lowest concentrations for each category. There was no association between plasma lignan concentrations and gastric cancer.


CONCLUSIONS
High serum concentrations of isoflavones were associated with a decreased risk for gastric cancer.


CONCLUSIONS
These results suggest a beneficial effect of high soybean product intake for gastric cancer risk.
Ko
Kwang-Pil
KP
Department of Preventive Medicine, Seoul National University College of Medicine, 103 Daehangno, Chongno-gu, Seoul 110-799, Korea.
Park
Sue K
SK
Park
Boyoung
B
Yang
Jae Jeong
JJ
Cho
Lisa Y
LY
Kang
Chungwon
C
Kim
Cheong Sik
CS
Gwack
Jin
J
Shin
Aesun
A
Kim
Yeonju
Y
Kim
Jeongseon
J
Yang
Han-Kwang
HK
Kang
Daehee
D
Chang
Soung-Hoon
SH
Shin
Hai-Rim
HR
Yoo
Keun-Young
KY
D000368:Aged; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007529:Isoflavones / Q000097:blood / Q000627:therapeutic use*; D007723:Korea; D008297:Male; D008875:Middle Aged; D048789:Phytoestrogens / Q000097:blood / Q000627:therapeutic use*; D012307:Risk Factors; D045730:Soy Foods; D013274:Stomach Neoplasms / Q000097:blood / Q000517:prevention & control*
D007529:Isoflavones; D048789:Phytoestrogens