Dietary Folate and Risk of Prostate Cancer in Italy

Abstract

Folate status may affect cancer risk through its role in both methylation and nucleotide synthesis of DNA. A low dietary intake of folate has been linked to risk of several cancers, but epidemiologic studies with reference to prostate cancer are scanty. We therefore analyzed data from a case-control study of prostate cancer conducted between 1991 and 2002 in various areas of Italy. Cases were 1,294 patients with incident, histologically confirmed prostate cancer and controls were 1,451 patients admitted to the same network of hospitals of cases for acute, nonneoplastic conditions. All subjects were <75 years old. Intake of folate and other nutrients was computed from a validated food frequency questionnaire. We adjusted for energy intake using the residual method, and calculated multivariate odds ratios (OR) and 95% confidence intervals (CI) using unconditional logistic regression. The OR of prostate cancer was 0.66 (95% CI, 0.51-0.85) for the highest versus the lowest quintile of folate intake. The relation between dietary folate and prostate cancer was consistent across strata of age, methionine, vitamin B6, and alcohol intake, and did not vary substantially according to Gleason score of prostate cancer. The combined OR for high-folate and low-alcohol intake versus low-folate and high-alcohol intake was 0.46 (95% CI, 0.29-0.75). Therefore, this study supports a favorable role of dietary folate on prostate cancer risk. (Cancer Epidemiol Biomarkers Prev 2005;14(4):944 -8)

One-Carbon Metabolism and Prostate Cancer Risk: Prospective Investigation of Seven Circulating B Vitamins and Metabolites

“…Previous studies of vitamin B6 and prostate cancer risk have yielded null or inverse associations (9,10,31,32). To our knowledge, the role of cysteine in prostate cancer has not previously been studied in an epidemiologic study.…”

“…As noted above, however, the lack of association between methionine and risk seems to contradict the methylation hypothesis in prostate cancer etiology. Null or weakly positive associations with prostate cancer risk have previously been reported for methionine (10,31).…”

Dietary factors of one-carbon metabolism and prostate cancer risk

“…Most other studies examining folate intake or status in relation to prostate cancer have been null (24,26,28,29), although one suggested that folate intake may be inversely associated with the risk of advanced prostate cancer (26). One case-control study reported a significant inverse association with folate intake (27), and a recent prospective study reported significant inverse associations with serum folate and prostate cancer incidence and mortality, and the patterns for red blood cell folate were similarly but nonsignificantly inverse (25). The associations between folate intake and prostate or other cancers (14,16,17,27) have been shown to be modified by alcohol intake.…”

“…These dietary factors related to one-carbon metabolism have been implicated in the development of several malignancies, including colon (14 -16), breast (17), pancreatic (18), lung (19), and cervical (20) cancers, and they may also affect the development of prostate cancer (21,22). In addition to one study of serum one-carbon factors in the ␣-Tocopherol, ␤-Carotene Cancer Prevention (ATBC) Study cohort (23), 3 prospective studies (24 -26) and one case-control study (27) reported on one-carbon nutrients and prostate cancer, and 2 other case-control studies included some one-carbon nutrients in a broad examination of dietary factors (28,29). The results of these studies have been mixed.…”

High serum folate is associated with reduced biochemical recurrence after radical prostatectomy: Results from the SEARCH Database

“…Results from a large randomized trial comparing folic acid supplementation versus placebo for reduction of colon adenoma development showed a secondary outcome of higher risk of prostate cancer in men receiving folic acid (4). Conversely, an Italian case-control study found lower folate intake (measure by questionnaire) was associated with higher risk of prostate cancer (9). Findings from the American Cancer Society Cancer Prevention Study II Nutrition Cohort demonstrated that neither dietary nor total folate intake were associated with incidence of prostate cancer (10).…”