Dietary folate and folate vitamers and the risk of prostate cancer in The Netherlands Cohort Study
ABSTRACT PURPOSE: The aim of the present study was to examine the association between intake of folate, and specific folate vitamers, and the risk of advanced and total prostate cancer. METHODS: The association between dietary folate and prostate cancer risk was evaluated in The Netherlands Cohort Study (NLCS) on diet and cancer, conducted among 58,279 men ages 55-69 years at baseline. Information on diet was collected at baseline by means of food frequency questionnaires. Incident cases were identified by record linkage with regional cancer registries and the Dutch National Database of Pathology Reports. After 17.3 years of follow-up, 3,669 incident prostate cancer cases, of which 1,290 advanced cases, and 2,336 male subcohort members were available for case-cohort analyses. RESULTS: Dietary folate was not associated with prostate cancer risk, nor with the risk of advanced prostate cancer, among men in the NLCS cohort (HR = 1.05, 95 % CI: 0.87-1.26 and HR = 1.09, 95 % CI: 0.88-1.35, respectively, for the highest quintile of folate intake vs. the lowest quintile). Specific folate vitamers were neither associated with the risk of prostate cancer or risk of advanced prostate cancer. CONCLUSIONS: Our results do not support an association of dietary folate or specific folate vitamers on the risk of prostate cancer, or advanced prostate cancer.
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ABSTRACT: While the importance of record linkage is widely recognised, few studies have attempted to quantify how linkage errors may have impacted on their own findings and outcomes. Even where authors of linkage studies have attempted to estimate sensitivity and specificity based on subjects with known status, the effects of false negatives and positives on event rates and estimates of effect are not often described.PLoS ONE 07/2014; 9(7):e103690. DOI:10.1371/journal.pone.0103690 · 3.53 Impact Factor
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ABSTRACT: Prostate cancer (PCa) remains a leading cause of mortality in US men and the prevalence continues to rise world-wide especially in countries where men consume a ‘Western-style’ diet. Epidemiologic, preclinical and clinical studies suggest a potential role for dietary intake on the incidence and progression of PCa. 'This minireview provides an overview of recent published literature with regard to nutrients, dietary factors, dietary patterns and PCa incidence and progression. Low carbohydrates intake, soy protein, omega-3 (w-3) fat, green teas, tomatoes and tomato products and zyflamend showed promise in reducing PCa risk or progression. A higher saturated fat intake and a higher β-carotene status may increase risk. A ‘U’ shape relationship may exist between folate, vitamin C, vitamin D and calcium with PCa risk. Despite the inconsistent and inconclusive findings, the potential for a role of dietary intake for the prevention and treatment of PCa is promising. The combination of all the beneficial factors for PCa risk reduction in a healthy dietary pattern may be the best dietary advice. This pattern includes rich fruits and vegetables, reduced refined carbohydrates, total and saturated fats, and reduced cooked meats. Further carefully designed prospective trials are warranted.BMC Medicine 12/2015; 13(1). DOI:10.1186/s12916-014-0234-y · 7.28 Impact Factor
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ABSTRACT: Studies have reported inconsistent results concerning the existence of associations of folate intake and serum folate levels with prostate cancer risk. This study sought to summarise the evidence regarding these relationships using a dose-response meta-analysis approach. In January 2014, we performed electronic searches of PubMed, Embase, and the Cochrane Library to identify studies examining the effect of folate on the incidence of prostate cancer. Only prospective studies that reported effect estimates with 95% confidence intervals (CIs) of the incidence of prostate cancer for more than 2 categories of folate were included. Overall, we included 10 prospective studies reporting data on 202,517 individuals. High dietary folate intake had little or no effect on prostate cancer risk (risk ratio [RR] = 1.02; 95%CI = 0.95-1.09; P = 0.598). The dose-response meta-analysis suggested that a 100 mug per day increase in dietary folate intake has no significant effect on the risk of prostate cancer (RR = 1.01; 95%CI = 0.99-1.02; P = 0.433). However, high serum folate levels were associated with an increased risk of prostate cancer (RR = 1.21; 95%CI = 1.05-1.39; P = 0.008). The dose-response meta-analysis indicated that a 5 nmol/L increment of serum folate levels was also associated with an increased risk of prostate cancer (RR = 1.04; 95%CI = 1.00-1.07; P = 0.042). Our study indicated that dietary folate intake had little or no effect on prostate cancer risk. However, increased serum folate levels have potentially harmful effects on the risk of prostate cancer.BMC Public Health 12/2014; 14(1):1326. DOI:10.1186/1471-2458-14-1326 · 2.32 Impact Factor