Folate Intake and Prostate Cancer Risk: A Case-Control Study

Abstract

Folate deficiency has been implicated in the carcinogenesis of several tumor types. The role of folate in prostate cancer remains indeterminate. We investigated folate as a risk factor for prostate cancer among 140 biopsy-confirmed prostate cancer patients, 230 age-matched clinic controls, and 250 negative prostate biopsy controls. Dietary folate intake was inversely associated with overall risk of prostate cancer as compared to clinic controls (P for a linear trend = 0.003). When stratified by disease severity, dietary folate and folate from natural sources were associated with reduced risk of high-grade cancer as compared to both clinic controls (P for a linear trend = 0.0009 and 0.02, respectively) and biopsy negative controls (P for a linear trend = 0.03 and 0.05, respectively). There was no interaction between alcohol consumption and folate intake. These analyses support an inverse association between dietary folate intake and prostate cancer risk and primarily risk of high-grade prostate cancer.

ACKNOWLEDGMENTS

This study was supported by United States Public Health Service grants 5 M01 RR000334, 1 UL1 RR024120–01, and K22CA94973 and the resources and facilities of the Portland Veterans Affairs Medical Center. VA Advanced Career Development Award (M. Garzotto) Biostatistics support was provided through the OHSU Cancer Institute Biostatistics Shared Resource (P30 CA069533-09) and the Oregon Clinical and Translational Research Institute (UL1 RR024140).

Notes

^a Abbreviations are as follows: PSA, prostate-specific antigen; BMI, body mass index; NSAID, nonsteroidal anti-inflammatory drug. P value for chi-square difference between cases and respective control groups,

∗P < 0.05,

∗∗∗P < 0.001, and between control groups,

^† P < 0.05.

^a Abbreviation is as follows: PSA, prostate-specific antigen. Wilcoxon 2-sample test for difference between means of cases and respective control groups,

∗P < 0.05,

∗∗P < 0.01, and between control groups

^† P < 0.05.

^a Abbbreviation is as follows: PSA, prostate-specific antigen. Unconditional logistic regression models adjusted for age, total caloric intake, race, body mass index (BMI), and family history of prostate cancer.

^b Unconditional logistic regression models adjusted for age, total caloric intake, race, BMI, family history of prostate cancer, and vitamin B6 intake.

^a Abbreviations are as follows: PSA, prostate-specific antigen; BMI, body mass index. Unconditional logistic regression models adjusted for age, total caloric intake, race, BMI, PSA, and family history of prostate cancer.

^b Unconditional logistic regression models adjusted for age–total caloric intake–race–BMI–PSA–family history of prostate cancer and vitamin B6 intake.