Folate intake and risk of pancreatic cancer: pooled analysis of prospective cohort studies.
BACKGROUND
Epidemiological studies evaluating the association between folate intake and risk of pancreatic cancer have produced inconsistent results. The statistical power to examine this association has been limited in previous studies partly because of small sample size and limited range of folate intake in some studies.


METHODS
We analyzed primary data from 14 prospective cohort studies that included 319,716 men and 542,948 women to assess the association between folate intake and risk of pancreatic cancer. Folate intake was assessed through a validated food-frequency questionnaire at baseline in each study. Study-specific relative risks (RRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models and then pooled using a random effects model. All statistical tests were two-sided.


RESULTS
During 7-20 years of follow-up across studies, 2195 pancreatic cancers were identified. No association was observed between folate intake and risk of pancreatic cancer in men and women (highest vs lowest quintile: dietary folate intake, pooled multivariable RR = 1.06, 95% CI = 0.90 to 1.25, P(trend) = .47; total folate intake [dietary folate and supplemental folic acid], pooled multivariable RR = 0.96, 95% CI = 0.80 to 1.16, P(trend) = .90). No between-study heterogeneity was observed (for dietary folate, P(heterogeneity) = .15; for total folate, P(heterogeneity) = .22).


CONCLUSIONS
Folate intake was not associated with overall risk of pancreatic cancer in this large pooled analysis.
Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA.
Ying
Y
Bao
Dominique S
DS
Michaud
Donna
D
Spiegelman
Demetrius
D
Albanes
Kristin E
KE
Anderson
Leslie
L
Bernstein
Piet A
PA
van den Brandt
Dallas R
DR
English
Jo L
JL
Freudenheim
Charles S
CS
Fuchs
Graham G
GG
Giles
Edward
E
Giovannucci
R Alexandra
RA
Goldbohm
Niclas
N
Håkansson
Pamela L
PL
Horn-Ross
Eric J
EJ
Jacobs
Cari M
CM
Kitahara
James R
JR
Marshall
Anthony B
AB
Miller
Kim
K
Robien
Thomas E
TE
Rohan
Arthur
A
Schatzkin
Victoria L
VL
Stevens
Rachael Z
RZ
Stolzenberg-Solomon
Jarmo
J
Virtamo
Alicja
A
Wolk
Regina G
RG
Ziegler
Stephanie A
SA
Smith-Warner
D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D005247:Feeding Behavior; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000494:pharmacology*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D010190:Pancreatic Neoplasms / Q000517:prevention & control*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D011795:Surveys and Questionnaires
D005492:Folic Acid