Pooled analyses of 13 prospective cohort studies on folate intake and colon cancer.
OBJECTIVE
Studies of folate intake and colorectal cancer risk have been inconsistent. We examined the relation with colon cancer risk in a series of 13 prospective studies.


METHODS
Study- and sex-specific relative risks (RRs) were estimated from the primary data using Cox proportional hazards models and then pooled using a random-effects model.


RESULTS
Among 725,134 participants, 5,720 incident colon cancers were diagnosed during follow-up. The pooled multivariate RRs (95% confidence interval [CI]) comparing the highest vs. lowest quintile of intake were 0.92 (95% CI 0.84-1.00, p-value, test for between-studies heterogeneity = 0.85) for dietary folate and 0.85 (95% CI 0.77-0.95, p-value, test for between-studies heterogeneity = 0.42) for total folate. Results for total folate intake were similar in analyses using absolute intake cutpoints (pooled multivariate RR = 0.87, 95% CI 0.78-0.98, comparing ≥ 560 mcg/days vs. <240 mcg/days, p-value, test for trend = 0.009). When analyzed as a continuous variable, a 2% risk reduction (95% CI 0-3%) was estimated for every 100 μg/day increase in total folate intake.


CONCLUSIONS
These data support the hypothesis that higher folate intake is modestly associated with reduced risk of colon cancer.
Kim
Dong-Hyun
DH
Department of Social and Preventive Medicine, College of Medicine, Hallym University, Chunchon, Korea.
Smith-Warner
Stephanie A
SA
Spiegelman
Donna
D
Yaun
Shiaw-Shyuan
SS
Colditz
Graham A
GA
Freudenheim
Jo L
JL
Giovannucci
Edward
E
Goldbohm
R Alexandra
RA
Graham
Saxon
S
Harnack
Lisa
L
Jacobs
Eric J
EJ
Leitzmann
Michael
M
Mannisto
Satu
S
Miller
Anthony B
AB
Potter
John D
JD
Rohan
Thomas E
TE
Schatzkin
Arthur
A
Speizer
Frank E
FE
Stevens
Victoria L
VL
Stolzenberg-Solomon
Rachael
R
Terry
Paul
P
Toniolo
Paolo
P
Weijenberg
Matty P
MP
Willett
Walter C
WC
Wolk
Alicja
A
Zeleniuch-Jacquotte
Anne
A
Hunter
David J
DJ
D015331:Cohort Studies; D003110:Colonic Neoplasms / Q000517:prevention & control*; D015179:Colorectal Neoplasms / Q000517:prevention & control*; D016001:Confidence Intervals; D004032:Diet; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage*; D006801:Humans; D015994:Incidence; D008297:Male; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012306:Risk
D005492:Folic Acid
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