Relation of plasma folate and methylenetetrahydrofolate reductase C677T polymorphism to colorectal adenomas.
BACKGROUND
Folate intake may be related to decreased risk of colorectal cancer and adenomas. Methylenetetrahydrofolate reductase (MTHFR) is a key regulatory enzyme in folate metabolism. We examined the relation between plasma folate status and colorectal adenomas with reference to effect modification by the genetic polymorphism (C677T) of MTHFR.


METHODS
Study subjects were middle-aged Japanese men: 177 cases of colorectal adenomas and 192 controls with normal total colonoscopy. Statistical adjustment was made for hospital, rank in the Self Defense Forces, alcohol use, smoking, and body mass index.


RESULTS
Plasma folate levels were slightly lower in adenoma cases than in controls. Adjusted odds ratio (OR) for high (>5.50 ng/ml) versus low plasma folate levels was 0.72 (95% CI: 0.46-1.14). As compared with subjects with the CC or CT genotype having low plasma folate levels, those with the TT genotype showed a decreased risk of colorectal adenomas when they had high levels of plasma folate (adjusted OR = 0.58, 95% CI: 0.21-1.61), and an increased risk when they had low folate levels (adjusted OR = 2.13, 95% CI: 0.82-5.54). There was no clear relation between plasma folate and colorectal adenomas among those with the CC or CT genotype.


CONCLUSIONS
The findings suggest an interaction between folate and the MTHFR genotype on colorectal adenomas.
Marugame
Tomomi
T
Department of Preventive Medicine, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan. marugame@phealth.med.kyushu-u.ac.jp
Tsuji
Emiko
E
Kiyohara
Chikako
C
Eguchi
Hiroyuki
H
Oda
Takashi
T
Shinchi
Koichi
K
Kono
Suminori
S
D000236:Adenoma / Q000097:blood / Q000235:genetics*; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000097:blood / Q000235:genetics*; D005492:Folic Acid / Q000097:blood* / Q000378:metabolism; D005838:Genotype; D006801:Humans; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D008875:Middle Aged; D016017:Odds Ratio; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics* / Q000378:metabolism; D011110:Polymorphism, Genetic; D012306:Risk
D005492:Folic Acid; D000587:Oxidoreductases Acting on CH-NH Group Donors; D042965:Methylenetetrahydrofolate Reductase (NADPH2)