Dietary folate intake and the risk of 11 types of cancer: a case-control study in Uruguay.
BACKGROUND
There is limited, but inconclusive, epidemiological evidence that high folate intake decreases the risk of colorectal and esophageal cancers. For other cancer sites, the evidence is even less consistent or extensive.


METHODS
We conducted a case-control study of dietary folate intake and risk of 11 cancer sites in Uruguay between 1996 and 2004, including 3539 cancer cases and 2032 hospital controls. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of cancer associated with folate intake.


RESULTS
In the multivariable model, there was a significant decrease in the risk of cancers of the oral cavity and pharynx (OR = 0.49, 95% CI 0.24-0.98), esophagus (OR = 0.29, 95% CI 0.14-0.60), upper aerodigestive tract (OR = 0.41, 95% CI 0.26-0.65), colorectum (OR = 0.42, 95% CI 0.23-0.76) and kidney (OR = 0.35, 95% CI 0.13-0.93) for the highest versus the lowest quartile of dietary folate intake.


CONCLUSIONS
Our results not only confirm earlier findings of decreased risk of colorectal and esophageal cancers with a high dietary folate intake but also suggest decreased risk of several other cancers. However, we cannot exclude the possibility that residual confounding, multiple comparisons or other forms of bias could explain these results.
Aune
D
D
Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK. d.aune@imperial.ac.uk
Deneo-Pellegrini
H
H
Ronco
A L
AL
Boffetta
P
P
Acosta
G
G
Mendilaharsu
M
M
De Stefani
E
E
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009369:Neoplasms / Q000145:classification / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D014583:Uruguay / Q000453:epidemiology
D005492:Folic Acid