Dietary intake of folate and alcohol, MTHFR C677T polymorphism, and colorectal cancer risk in Korea.
BACKGROUND
The incidence of colorectal cancer (CRC) is increasing sharply in Korea, and evidence has suggested the role of dietary methyl supply and related polymorphisms on colorectal carcinogenesis.


OBJECTIVE
We investigated the association between folate and alcohol intake, methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism, and CRC risk in Koreans.


METHODS
A total of 787 cases and 656 controls were recruited from 2 university hospitals. Multiple logistic regression models were used to estimate ORs and corresponding 95% CIs.


RESULTS
MTHFR 677T homozygotes were at a lower risk of CRC (OR: 0.60; 95% CI: 0.46, 0.78 for TT compared with CC/CT). High folate intake was associated with reduced CRC risk (OR: 0.64; 95% CI: 0.49, 0.84 for high compared with low intake), and high alcohol consumption was associated with increased risk of CRC (OR: 1.76; 95% CI: 1.26, 2.46 for high compared with low intake). When data were stratified by the amount of dietary methyl (combined intake of folate and alcohol), those with low-methyl diets had higher risk of CRC (OR: 2.32; 95% CI: 1.18, 4.56) than did those with high-methyl diets among CC/CT carriers, whereas the amount of dietary methyl did not affect the CRC risk among carriers with the TT homozygous variant. This association was stronger in patients with colon cancer than in patients with rectal cancer.


CONCLUSIONS
We found that the effect of dietary methyl supply on colorectal carcinogenesis may differ according to MTHFR C677T genotype and the subsite of origin in a Korean population.
Cancer Epidemiology Branch, National Cancer Center, Goyang, South Korea.
Jeongseon
J
Kim
Young Ae
YA
Cho
Dong-Hyun
DH
Kim
Bong-Hwa
BH
Lee
Dae-Yong
DY
Hwang
Jinyoung
J
Jeong
Hun-Jae
HJ
Lee
Keitaro
K
Matsuo
Kazuo
K
Tajima
Yoon-Ok
YO
Ahn
D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects*; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000209:etiology / Q000235:genetics* / Q000517:prevention & control; D004032:Diet; D000431:Ethanol / Q000009:adverse effects*; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage / Q000627:therapeutic use*; D006720:Homozygote; D006801:Humans; D007723:Korea; D016015:Logistic Models; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D008875:Middle Aged; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D012307:Risk Factors; D014803:Vitamin B Complex / Q000008:administration & dosage / Q000627:therapeutic use
D014803:Vitamin B Complex; D000431:Ethanol; D005492:Folic Acid; D042965:Methylenetetrahydrofolate Reductase (NADPH2)