A prospective analysis of the association between dietary fiber intake and prostate cancer risk in EPIC

Dietary Fiber Intake and Risk of Advanced and Aggressive Forms of Prostate Cancer: A Pooled Analysis of 15 Prospective Cohort Studies

BACKGROUND

Evidence of an association between dietary fiber intake and risk of advanced and aggressive forms of prostate cancer (PC) and PC mortality is limited.

OBJECTIVE

The aim of this study was to examine associations between intakes of dietary fiber overall and by food source and risk of advanced and aggressive forms of PC.

DESIGN

The study design was a pooled analysis of the primary data from 15 cohorts in 3 continents. Baseline dietary fiber intake was assessed using a validated food frequency questionnaire or diet history in each study.

PARTICIPANTS/SETTING

There were 842 149 men followed for up to 9 to 22 years between 1985 and 2009 across studies.

MAIN OUTCOME MEASURES

The primary outcome measures were advanced (stage T4, N1, or M1 or PC mortality), advanced restricted (excluded men with missing stage and those with localized PC who died of PC), and high-grade PC (Gleason score ≥8 or poorly differentiated/undifferentiated) and PC mortality.

STATISTICAL ANALYSIS PERFORMED

Study-specific multivariable hazard ratios (MVHR) were calculated using Cox proportional hazards regression and pooled using random effects models.

RESULTS

Intake of dietary fiber overall, from fruits, and from vegetables was not associated with risk of advanced (n = 4863), advanced restricted (n = 2978), or high-grade PC (n = 9673) or PC mortality (n = 3097). Dietary fiber intake from grains was inversely associated with advanced PC (comparing the highest vs lowest quintile, MVHR 0.84; 95% CI 0.76-0.93), advanced restricted PC (MVHR 0.85; 95% CI 0.74-0.97), and PC mortality (MVHR 0.78; 95% CI 0.68-0.89); statistically significant trends were noted for each of these associations (P ≤ .03), and a null association was observed for high-grade PC for the same comparison (MVHR 1.00; 95% CI 0.93-1.07). The comparable results were 1.06 (95% CI 1.01-1.10; P value, test for trend = .002) for localized PC (n = 35,199) and 1.05 (95% CI 0.99-1.11; P value, test for trend = .04) for low/intermediate grade PC (n = 34 366).

CONCLUSIONS

Weak nonsignificant associations were observed between total dietary fiber intake and risk of advanced forms of PC, high-grade PC, and PC mortality. High dietary fiber intake from grains was associated with a modestly lower risk of advanced forms of PC and PC mortality.

Different Sources of Fiber Intake and Risk of 17 Specific Cancers and All Cancers Combined: Prospective Study of 364,856 Participants in the UK Biobank

Inverse associations between dietary fiber (DF) and colorectal cancer risk are well-established. However, evidence is limited in relation to other cancer sites. This study, of 364,856 participants from the UK Biobank, aimed to evaluate the associations between total and source-specific partial DF and risk of 17 specific cancers and all cancers combined. Partial DF was derived from baseline touchscreen questionnaire data on cereal, bread, fruit, and vegetable intake. The outcomes were incident cancer at 17 sites and all cancers combined. Cox proportional hazards models were applied. Over a median 8.8-year follow-up period, 30,725 people were diagnosed with cancer. After adjusting for sociodemographic and lifestyle factors, those in the highest quintile of partial DF compared with the lowest quintile (<9.6 vs ≥19.1 g/day) had 10% lower risk of cancer overall, with the greatest risk reductions observed for cervical (hazard ratio (HR) = 0.33, 95% confidence interval (CI): 0.14; 0.82), esophageal (HR = 0.66, 95% CI: 0.52; 0.84), lung (HR = 0.67, 95% CI: 0.59; 0.76), bladder (HR = 0.72, 95% CI: 0.56; 0.91), and kidney (HR = 0.75, 95% CI: 0.61; 0.92) cancers. Associations between DF and lung cancer were observed only in current and former smokers. Higher DF intake, in particular cereal fiber and fruit and vegetable fiber, was associated with a lower risk of overall and multiple site-specific cancers.

Higher insoluble fiber intake is associated with a lower risk of prostate cancer: results from the PLCO cohort

Studies regarding the relationship between fiber intake and prostate cancer (PCa) have conflicting results. Therefore, this study examined the relationship between fiber intake and the risk of PCa by using data from Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. A total of 54,336 participants in the United States, consisting of 6,414 patients with PCa, were included in this study. Multivariate Cox regression models were applied to estimate adjusted hazard ratios (aHRs) and corresponding 95% confidence intervals (CIs). Compared with individuals in the lowest quartile, individuals in the highest quartile of insoluble fiber intake had a significantly lower risk of PCa (aHR, 0.87; 95% CI, 0.78-0.98). By contrast, no significant associations were detected between total fiber intake (aHR, 0.90; 95% CI, 0.80-1.01) or soluble fiber intake (aHR, 0.90; 95% CI, 0.80-1.02). Subgroup analyses showed that insoluble fiber was related to a decreased risk of PCa in subjects with the following characteristics: age > 65 years, nonsmoking or former smokers, education level ≤ high school, non-Hispanic white ethnicity, or without a family history of PCa. In addition, significant combined effects of insoluble fiber intake, age and family history of PCa on the risk of PCa were observed, but no combined effects of smoking status and insoluble fiber intake were observed. In addition, total fiber, insoluble fiber, and soluble fiber intake had no influence on the mortality of PCa patients. These results show that all 3 measures of fiber suggest a protective association, but insoluble fiber may have a stronger association with the risk of PCa. Future studies are warranted to further investigate these relationships.

Evidence Update on the Relationship between Diet and the Most Common Cancers from the European Prospective Investigation into Cancer and Nutrition (EPIC) Study: A Systematic Review

The European Prospective Investigation into Cancer and Nutrition (EPIC) is a multicentre prospective study conducted in 23 centres in 10 European countries. Here we review the findings from EPIC on the relationship between diet-related exposures and incidence or mortality from the four most frequent cancers in the European population: colorectal, breast, lung, and prostate cancer. We conducted a systematic review following PRISMA guidelines and identified 110 high-quality studies based on the EPIC cohort. Fruit and vegetable consumption had a protective effect against colorectal, breast, and lung cancer, whereas only fruit had a protective effect against prostate cancer. A higher consumption of fish and lower consumption of red and processed meat were related with a lower risk of colorectal cancer; and higher consumption of fatty fish with lower risk of breast cancer. Calcium and yogurt intake were found to protect against colorectal and prostate cancer. Alcohol consumption increased the risk for colorectal and breast cancer. Finally, adherence to the Mediterranean diet emerged as a protective factor for colorectal and breast cancer. The EPIC study results are in agreement with the latest evidence from leading authorities on cancer prevention and help to inform public prevention policies and strategies.

Pre-diagnostic carbohydrate intake and treatment failure after radical prostatectomy for early-stage prostate cancer

PURPOSE

An association between dietary carbohydrate intake and prostate cancer (PCa) prognosis is biologically plausible, but data are scarce. This prospective cohort study examined the relation between pre-diagnostic carbohydrate intake and treatment failure following radical prostatectomy for clinically early-stage PCa.

METHODS

We identified 205 men awaiting radical prostatectomy and assessed their usual dietary intake of carbohydrates using the 110-item Block food frequency questionnaire. We also evaluated carbohydrate intake quality using a score based on the consumption of sugars relative to fiber, fat, and protein. Logistic regression analyzed their associations with the odds of treatment failure, defined as a detectable and rising serum prostate-specific antigen (PSA) or receiving androgen deprivation therapy (ADT) within 2 years.

RESULTS

Sucrose consumption was associated with a higher odds and fiber consumption with a lower odds of ADT after accounting for age, race/ethnicity, body mass index, and tumor characteristics (odds ratio [OR] (95% confidence interval [CI]) 5.68 (1.71, 18.9) for 3rd vs. 1st sucrose tertile and 0.88 (0.81, 0.96) per gram of fiber/day, respectively). Increasing carbohydrate intake quality also associated with a lower odds of ADT (OR (95% CI) 0.78 (0.66, 0.92) per unit increase in score, range 0-12).

CONCLUSIONS

Pre-diagnostic dietary carbohydrate intake composition and quality influence the risk of primary treatment failure for early-stage PCa. Future studies incorporating molecular aspects of carbohydrate metabolism could clarify possible underlying mechanisms.

A Pooled Analysis of 15 Prospective Cohort Studies on the Association between Fruit, Vegetable, and Mature Bean Consumption and Risk of Prostate Cancer

Background: Relationships between fruit, vegetable, and mature bean consumption and prostate cancer risk are unclear.Methods: We examined associations between fruit and vegetable groups, specific fruits and vegetables, and mature bean consumption and prostate cancer risk overall, by stage and grade, and for prostate cancer mortality in a pooled analysis of 15 prospective cohorts, including 52,680 total cases and 3,205 prostate cancer-related deaths among 842,149 men. Diet was measured by a food frequency questionnaire or similar instrument at baseline. We calculated study-specific relative risks using Cox proportional hazards regression, and then pooled these estimates using a random effects model.Results: We did not observe any statistically significant associations for advanced prostate cancer or prostate cancer mortality with any food group (including total fruits and vegetables, total fruits, total vegetables, fruit and vegetable juice, cruciferous vegetables, and tomato products), nor specific fruit and vegetables. In addition, we observed few statistically significant results for other prostate cancer outcomes. Pooled multivariable relative risks comparing the highest versus lowest quantiles across all fruit and vegetable exposures and prostate cancer outcomes ranged from 0.89 to 1.09. There was no evidence of effect modification for any association by age or body mass index.Conclusions: Results from this large, international, pooled analysis do not support a strong role of collective groupings of fruits, vegetables, or mature beans in prostate cancer.Impact: Further investigation of other dietary exposures, especially indicators of bioavailable nutrient intake or specific phytochemicals, should be considered for prostate cancer risk. Cancer Epidemiol Biomarkers Prev; 26(8); 1276-87. ©2017 AACR.

Consumption of whole grains and cereal fiber in relation to cancer risk: a systematic review of longitudinal studies

CONTEXT

Evidence from previous reviews is supportive of the hypothesis that whole grains may protect against various cancers. However, the reviews did not report risk estimates for both whole grains and cereal fiber and only case-control studies were evaluated. It is unclear whether longitudinal studies support this conclusion.

OBJECTIVE

To evaluate associations between whole grains and cereal fiber in relation to risk of lifestyle-related cancers data from longitudinal studies was evaluated.

DATA SOURCES

The following 3 databases were systematically searched: PubMed, EMBASE, and Cochrane CENTRAL.

STUDY SELECTION

A total of 43 longitudinal studies conducted in Europe and North America that reported multivariable-adjusted risk estimates for whole grains (n = 14), cereal fiber (n = 23), or both (n = 6) in relation to lifestyle-related cancers were included.

DATA EXTRACTION

Information on study location, cohort name, follow-up duration, sample characteristics, dietary assessment method, risk estimates, and confounders was extracted.

DATA SYNTHESIS

Of 20 studies examining whole grains and cancer, 6 studies reported a statistically significant 6%-47% reduction in risk, but 14 studies showed no association. Of 29 studies examining cereal fiber intake in relation to cancer, 8 showed a statistically significant 6%-49% reduction in risk, whereas 21 studies reported no association.

CONCLUSIONS

This systematic review concludes that most studies were suggestive of a null association. Whole grains and cereal fiber may protect against gastrointestinal cancers, but these findings require confirmation in additional studies.

Dietary fiber, whole grains, carbohydrate, glycemic index, and glycemic load in relation to risk of prostate cancer

BACKGROUND

The relationships between dietary fiber, whole grains, carbohydrate, glycemic index (GI), glycemic load (GL), and prostate cancer risk are unclear. We conducted a systematic review and meta-analysis to investigate these associations.

METHODS

Relevant studies were identified by a search of PubMed database and EMBASE database up to April 2015. A random effects model was used to calculate the summary relative risks (RRs) and their corresponding 95% confidence intervals (CIs).

RESULTS

Twenty-seven epidemiological studies (18 case-control studies and nine cohort studies) were included in the final analysis. The pooled RRs of prostate cancer were 0.94 (95% CI 0.85-1.05, P=0.285), 1.13 (95% CI 0.98-1.30, P=0.095), 0.96 (95% CI 0.81-1.14, P=0.672), 1.06 (95% CI 0.96-1.18, P=0.254), and 1.04 (95% CI 0.91-1.18, P=0.590) for dietary fiber, whole grains, carbohydrate, GI, and GL, respectively. There was no evidence of significant publication bias based on the Begg's test and Egger's test.

CONCLUSION

The findings of this meta-analysis indicate that, based on available information, dietary fiber, whole grains, carbohydrate, GI, and GL are not associated with the risk of prostate cancer.

No association between fiber intake and prostate cancer risk: a meta-analysis of epidemiological studies

Background

The findings of epidemiologic studies on the association between fiber intake and prostate cancer risk remain conflicting. We aimed to examine this association by conducting a meta-analysis of epidemiological studies.

Methods

Relevant studies were identified by PubMed (1966 to March 2015) and Embase (1974 to March 2015) database search through March 2015. We included epidemiological studies that reported relative risks (RRs) or odds ratios (ORs) with 95 % confidence intervals (CIs) for the association between dietary fiber intake and prostate cancer risk. Random effects models were used to calculate the summary risk estimates.

Results

For the highest compared with the lowest dietary fiber intake, a significantly decreased risk with prostate cancer was observed in case-control studies (OR = 0.82; 95 % CI, 0.68–0.96), but not in cohort studies (RR = 0.94; 95 % CI, 0.77–1.11). The combined risk estimate of all studies was 0.89 (95 % CI, 0.77, 1.01). A significant heterogeneity was observed across studies (p = 0.005). There was no evidence of significant publication bias based on Begg’s funnel plot (p = 0.753) or Egger’s test (p = 0.946).

Conclusions

This meta-analysis suggests the absence of evidence for association between dietary fiber intake and prostate cancer risk.

Fiber intake and risk of subsequent prostate cancer in Japanese men

BACKGROUND

Dietary fiber may reduce the risk of prostate cancer, possibly by increasing circulating concentrations of sex hormone-binding globulin and improving insulin sensitivity. However, results from previous epidemiologic studies of fiber intake and prostate cancer are inconsistent, and to our knowledge, no study has comprehensively evaluated the effects of soluble and insoluble fiber on prostate cancer in Asia.

OBJECTIVE

The objective was to examine the association between fiber intake and prostate cancer in Japanese men.

DESIGN

We conducted a population-based prospective study in 43,435 Japanese men aged 45-74 y. Participants responded to a validated questionnaire, which included 138 food items. Follow-up was from 1995 through 2009. HRs and 95% CIs of incidence were calculated according to quartiles of fiber intake.

RESULTS

During the 11.6-y follow-up, of the 825 men newly diagnosed with prostate cancer, 213 had advanced-stage cancer, 582 had organ-localized disease, and 30 had an undetermined stage of disease. Among them, 217 cases were detected by subjective symptoms. Total fiber was not associated with total or advanced prostate cancer, with respective multivariable HRs for the highest and lowest quartiles of 1.00 (95% CI: 0.77, 1.29; P-trend = 0.97) and 0.67 (95% CI: 0.42, 1.07; P-trend = 0.30). Total fiber and insoluble fiber intake were associated with a decreased risk of advanced cancers detected by subjective symptoms, with multivariate HRs (95% CIs) across increasing quartiles of 1.00, 0.58, 0.62, and 0.44 (0.21, 0.92; P-trend = 0.05) for total fiber and 1.00, 0.60, 0.52, and 0.46 (0.22, 0.93; P-trend = 0.04) for insoluble fiber. Soluble fiber intake showed no association with prostate cancer.

CONCLUSIONS

Dietary fiber is inversely associated with advanced prostate cancer detected by subjective symptoms even among populations with relatively low intake, such as Japanese. These results suggest that a very low intake of dietary fiber is associated with an increased risk of prostate cancer.

The health benefits of whole grains and fibre

Purpose

– The purpose of this paper is to evaluate the latest mounting evidence reporting associations between the important role of whole grains and fibre in lowering the risk of chronic diseases and health.

Design/methodology/approach

– A general systematic review was conducted to locate and summarise up-to-date published studies within the field. A Medline search identified human-controlled trials and observational studies published in the past five years.

Findings

– A total of 49 studies were identified. In observational studies, higher intakes of whole grain and dietary fibre were associated with a significantly lower risk of cardiovascular disease, diabetes, abdominal adiposity and certain cancers. This was further supported by human intervention trials, which reported benefits for appetite control, blood lipid levels, glycaemic control, digestive health and secondary cancer prevention. Mechanisms may relate to the micronutrients and phytonutrients present in high fibre foods.

Practical implications

– Practical advice is needed to help people identify foods rich in whole grains, e.g. breakfast cereals. UK fibre recommendations should be aligned with European guidelines and food labelling regulations, and a whole grain dietary recommendation, e.g. similar to the US guideline of three portions a day, could be introduced. Government and industry should play a role in communicating dietary fibre guidelines and the health benefits associated with whole grain and fibre, particularly insoluble fibre.

Originality/value

– This paper develops knowledge about whole grains, health and the importance of establishing whole-grain dietary recommendations.

Fruit, vegetable, and fiber intake in relation to cancer risk: findings from the European Prospective Investigation into Cancer and Nutrition (EPIC)

Fruit, vegetables, and certain components of plant foods, such as fiber, have long been thought to protect against cancer. The European Prospective Investigation into Cancer and Nutrition (EPIC) is a prospective cohort that includes >500,000 participants from 10 European countries and has made a substantial contribution to knowledge in this research area. The purpose of this article is to summarize the findings published thus far from the EPIC study on the associations between fruit, vegetable, or fiber consumption and the risk of cancer at 14 different sites. The risk of cancers of the upper gastrointestinal tract was inversely associated with fruit intake but was not associated with vegetable intake. The risk of colorectal cancer was inversely associated with intakes of total fruit and vegetables and total fiber, and the risk of liver cancer was also inversely associated with the intake of total fiber. The risk of cancer of the lung was inversely associated with fruit intake but was not associated with vegetable intake; this association with fruit intake was restricted to smokers and might be influenced by residual confounding due to smoking. There was a borderline inverse association of fiber intake with breast cancer risk. For the other 9 cancer sites studied (stomach, biliary tract, pancreas, cervix, endometrium, prostate, kidney, bladder, and lymphoma) there were no reported significant associations of risk with intakes of total fruit, vegetables, or fiber.

Dietary total and insoluble fiber intakes are inversely associated with prostate cancer risk

Although experimental data suggest a potentially protective involvement of dietary fiber in prostate carcinogenesis, very few prospective studies have investigated the relation between dietary fiber intake and prostate cancer risk, and those have had inconsistent results. Our objective was to study the association between dietary fiber intake (overall, insoluble, soluble, and from different sources, such as cereals, vegetables, fruits, and legumes) and prostate cancer risk. Stratifications by excess weight status, insulin-like growth factors, and amount of alcohol intake were also considered. This prospective analysis included 3313 men from the Supplémentation en Vitamines et Minéraux Antioxydants (SU.VI.MAX) cohort who completed at least 3 24-h dietary records. One hundred thirty-nine incident prostate cancers were diagnosed between 1994 and 2007 (median follow-up of 12.6 y). Associations between quartiles of energy-adjusted dietary fiber intake and prostate cancer risk were characterized by multivariate Cox proportional hazards models. Prostate cancer risk was inversely associated with total dietary fiber intake (HR of quartile 4 vs. quartile 1 = 0.47; 95% CI: 0.27, 0.81; P = 0.001), insoluble (HR = 0.46; 95% CI: 0.27, 0.78; P = 0.001), and legume (HR = 0.55; 95% CI: 0.32, 0.95; P = 0.04) fiber intakes. In contrast, we found no association between prostate cancer risk and soluble (P = 0.1), cereal (P = 0.7), vegetable (P = 0.9), and fruit (P = 0.4) fiber intakes. In conclusion, dietary fiber intake (total, insoluble, and from legumes but not soluble or from cereals, vegetables, and fruits) was inversely associated with prostate cancer risk, consistent with mechanistic data.

Nutrition, hormones and prostate cancer risk: results from the European prospective investigation into cancer and nutrition

Nutritional factors may influence the risk of developing prostate cancer, but understanding of this topic is poor. This chapter discusses research on this subject, mostly from the European Prospective Investigation into Cancer and Nutrition (EPIC), a cohort which includes 150,000 men recruited in the 1990s in eight European countries. So far the EPIC collaborators have published analyses of the relationship of prostate cancer risk with the intake of a range of foods and nutrients, and with blood-based markers of nutritional factors, on up to nearly 3,000 incident cases of prostate cancer. Most of the results of these analyses have been null, with no clear indication that the risk for prostate cancer is related to intakes of meat, fish, fruit, vegetables, fibre, fat or alcohol or with blood levels of fatty acids, carotenoids, tocopherols, B vitamins, vitamin D, or selenium. There is some evidence from EPIC that risk may be increased in men with a high intake of protein from dairy products, and analyses of hormone levels have shown that risk is higher in men with relatively high blood levels of insulin-like growth factor-I (IGF-I). More research is needed to better describe the relationships of prostate cancer risk with IGF-I and related hormones, and to better understand whether nutritional factors may influence risk through hormones or perhaps by other mechanisms.

Plasma alkylresorcinol metabolites as biomarkers for whole-grain intake and their association with prostate cancer: a Swedish nested case-control study

BACKGROUND

Observational studies have mostly found no association between self-reported whole-grain intake and prostate cancer. Plasma alkylresorcinol metabolites have been suggested as biomarkers for whole-grain intake in free-living populations.

METHODS

We investigated the major dietary and lifestyle determinants of plasma alkylresorcinol metabolites in a nested case-control study (1,016 cases and 1,817 controls) in the Malmö Diet and Cancer Study. Multivariate adjusted ORs and 95% confidence intervals (95% CI) were estimated to assess the association between plasma alkylresorcinol metabolites and prostate cancer using logistic regression.

RESULTS

Whole-grain intake, waist circumference, educational level, and smoking status were the main determinants of alkylresorcinol metabolites. We observed significant correlations between alkylresorcinol metabolites and whole-grain (r = 0.31) and fiber (r = 0.27) intake. Metabolite concentration was positively associated with prostate cancer risk (Poverall effect = 0.0004) but the association was not linear (P = 0.04). The lowest risk was seen among men with moderate plasma concentrations. The OR for high compared with moderate plasma alkylresorcinol metabolites was 1.41 (95% CI, 1.10-1.80) for prostate cancer.

CONCLUSIONS

Results suggest that plasma alkylresorcinol metabolites are mainly determined by whole-grain intake in this nested case-control study of Swedish men. The increased risk of prostate cancer seen among men with high plasma alkylresorcinol metabolites requires further study, but residual confounding, detection bias, or competing risks of nonprostate cancer-related deaths are plausible explanations that could not be ruled out.

IMPACT

We found no evidence of a protective effect of whole grains on incident prostate cancer. Further validation of alkylresorcinol metabolites as a biomarker for whole-grain intake is needed.

Dietary intakes of carbohydrates in relation to prostate cancer risk: a prospective study in the Malmö Diet and Cancer cohort

BACKGROUND

Dietary carbohydrates have been implicated in relation to prostate cancer.

OBJECTIVE

Our objective was to examine the associations between dietary intakes of carbohydrates, fiber, and their food sources and risk of prostate cancer, overall and by case severity, in the Malmö Diet and Cancer cohort.

DESIGN

The analysis included 8128 men aged 45-73 y without a history of cancer, cardiovascular disease, or diabetes and who were classified as adequate energy reporters. After a median follow-up time of 15 y, prostate cancer was diagnosed in 817 men. We used Cox proportional hazards regression to model associations between energy-adjusted nutrient and food intakes with risk of incident prostate cancer, with competing risk of death from non-prostate cancer causes taken into account.

RESULTS

After adjustment for age and other known or potential risk factors, we observed no associations between total carbohydrates or dietary fiber and prostate cancer. We observed positive associations between the intake of low-fiber cereals with overall and low-risk prostate cancer and between intakes of cake and biscuits and rice and pasta with low-risk prostate cancer (all P-trend < 0.05). A high intake compared with zero consumption of sugar-sweetened beverages was associated with increased risk of symptomatic prostate cancer (HR: 1.38; 95% CI: 1.04, 1.84).

CONCLUSIONS

Results from this large study with high-validity dietary data suggest that a high intake of refined carbohydrates may be associated with increased risk of prostate cancer. However we observed no significant associations with high-risk prostate cancer, and not all foods that are typically high in refined carbohydrates were associated with prostate cancer.

Intake of grains and dietary fiber and prostate cancer aggressiveness by race

Purpose. To examine the associations among intake of refined grains, whole grains and dietary fiber and aggressiveness of prostate cancer in African Americans (AA, n = 930) and European Americans (EA, n = 993) in a population-based, case-only study (The North Carolina-Louisiana Prostate Cancer Project, PCaP). Methods. Prostate cancer aggressiveness was categorized as high, intermediate or low based on Gleason grade, PSA level and clinical stage. Dietary intake was assessed utilizing the NCI Diet History Questionnaire. Logistic regression (comparing high to intermediate/low aggressive cancers) and polytomous regression with adjustment for potential confounders were used to determine odds of high prostate cancer aggressiveness with intake of refined grains, whole grains and dietary fiber from all sources. Results. An inverse association with aggressive prostate cancer was observed in the 2nd and 3rd tertiles of total fiber intake (OR = 0.70; 95% CI, 0.50–0.97 and OR = 0.61; 95% CI, 0.40–0.93, resp.) as compared to the lowest tertile of intake. In the race-stratified analyses, inverse associations were observed in the 3rd tertile of total fiber intake for EA (OR = 0.44; 95% CI, 0.23–0.87) and the 2nd tertile of intake for AA (OR = 0.57; 95% CI, 0.35–0.95). Conclusions. Dietary fiber intake was inversely associated with aggressive prostate cancer among both AA and EA men.

Fiber intake and total and cause-specific mortality in the European Prospective Investigation into Cancer and Nutrition cohort

BACKGROUND

Previous studies have shown that high fiber intake is associated with lower mortality. However, little is known about the association of dietary fiber with specific causes of death other than cardiovascular disease (CVD).

OBJECTIVE

The aim of this study was to assess the relation between fiber intake, mortality, and cause-specific mortality in a large European prospective study of 452,717 men and women.

DESIGN

HRs and 95% CIs were estimated by using Cox proportional hazards models, stratified by age, sex, and center and adjusted for education, smoking, alcohol consumption, BMI, physical activity, total energy intake, and, in women, ever use of menopausal hormone therapy.

RESULTS

During a mean follow-up of 12.7 y, a total of 23,582 deaths were recorded. Fiber intake was inversely associated with total mortality (HR(per 10-g/d increase): 0.90; 95% CI: 0.88, 0.92); with mortality from circulatory (HR(per 10-g/d increase): 0.90 and 0.88 for men and women, respectively), digestive (HR: 0.61 and 0.64), respiratory (HR: 0.77 and 0.62), and non-CVD noncancer inflammatory (HR: 0.85 and 0.80) diseases; and with smoking-related cancers (HR: 0.86 and 0.89) but not with non-smoking-related cancers (HR: 1.05 and 0.97). The associations were more evident for fiber from cereals and vegetables than from fruit. The associations were similar across BMI and physical activity categories but were stronger in smokers and participants who consumed >18 g alcohol/d.

CONCLUSIONS

Higher fiber intake is associated with lower mortality, particularly from circulatory, digestive, and non-CVD noncancer inflammatory diseases. Our results support current recommendations of high dietary fiber intake for health maintenance.

Is concordance with World Cancer Research Fund/American Institute for Cancer Research guidelines for cancer prevention related to subsequent risk of cancer? Results from the EPIC study

BACKGROUND

In 2007 the World Cancer Research Fund (WCRF) and the American Institute of Cancer Research (AICR) issued 8 recommendations (plus 2 special recommendations) on diet, physical activity, and weight management for cancer prevention on the basis of the most comprehensive collection of available evidence.

OBJECTIVE

We aimed to investigate whether concordance with the WCRF/AICR recommendations was related to cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) study.

DESIGN

The present study included 386,355 EPIC participants from 9 European countries. At recruitment, dietary, anthropometric, and lifestyle information was collected. A score was constructed based on the WCRF/AICR recommendations on weight management, physical activity, foods and drinks that promote weight gain, plant foods, animal foods, alcoholic drinks, and breastfeeding for women; the score range was 0-6 for men and 0-7 for women. Higher scores indicated greater concordance with WCRF/AICR recommendations. The association between the score and cancer risk was estimated by using multivariable Cox regression models.

RESULTS

Concordance with the score was significantly associated with decreased risk of cancer. A 1-point increment in the score was associated with a risk reduction of 5% (95% CI: 3%, 7%) for total cancer, 12% (95% CI: 9%, 16%) for colorectal cancer, and 16% (95% CI: 9%, 22%) for stomach cancer. Significant associations were also observed for cancers of the breast, endometrium, lung, kidney, upper aerodigestive tract, liver, and esophagus but not for prostate, ovarian, pancreatic, and bladder cancers.

CONCLUSION

Adherence to the WCRF/AICR recommendations for cancer prevention may lower the risk of developing most types of cancer.

[Epidemiology of prostate cancer]

Since a number of years, prostate cancer has been the most frequent cancer site among men in Germany and has replaced lung cancer as the leading position. Among the most frequent cancer sites, it is the one with the lowest available knowledge about etiology. Smoking and alcohol apparently do not play a role. Regarding food intake, indications exist for a protective association to tomatoes or lycopene consumption and a protective association was also seen with high physical activity, while risk seems to be elevated in obese men. Associations to hormonal factors have been observed and are under consideration. Trials with potential chemopreventive agents have been unsuccessful so far. For early detection, digital rectal examination has been part of the German statutory early detection program" from the very beginning in 1971 and the test for prostate specific antigen (PSA) is being used in the framework of the so-called individual health services, both without scientific evidence of effectiveness. The available data show that the progression of prostate cancer to the leading male cancer site was chiefly driven by the unstructured introduction of the PSA test as a screening tool. Cynically addressed, the figures indicate that the most efficient known preventive intervention was not to attend screening. This delicate situation should, however, not discourage from further examinations of prostate cancer screening. Recent results including the European randomized prostate cancer screening study (ERSPC) indicated that intelligently structured screening, possibly even using the PSA test, might be effective. Before routine application the novel approaches also have to be scrutinized in a research setting.

Cancer Risk and Behavioral Factors, Comorbidities, and Functional Status in the US Elderly Population

About 80% of all cancers are diagnosed in the elderly and up to 75% of cancers are associated with behavioral factors. An approach to estimate the contribution of various measurable factors, including behavior/lifestyle, to cancer risk in the US elderly population is presented. The nationally representative National Long-Term Care Survey (NLTCS) data were used for measuring functional status and behavioral factors in the US elderly population (65+), and Medicare Claims files linked to each person from the NLTCS were used for estimating cancer incidence. The associations (i.e., relative risks) of selected factors with risks of breast, prostate, lung and colon cancers were evaluated and discussed. Behavioral risk factors significantly affected cancer risks in the US elderly. The most influential of potentially preventable risk factors can be detected with this approach using NLTCS-Medicare linked dataset and for further deeper analyses employing other datasets with detailed risk factors description.

Dietary glycemic index, glycemic load, insulin index, fiber and whole-grain intake in relation to risk of prostate cancer

OBJECTIVE

Insulin may play a role in prostate cancer tumorigenesis. Postprandial blood glucose and insulin responses of foods depend importantly on the carbohydrate quality and quantity, represented by glycemic index (GI), glycemic load (GL), fiber and whole-grain content, but are also influenced by intake of protein and other characteristics. The recently developed insulin index (II) quantifies the postprandial insulin secretion, also taking into account these additional characteristics.

METHODS

We investigated the association between dietary GI, GL, II, fiber, and whole grains and risk of total prostate cancer (n = 5,112) and subgroups of prostate cancer as defined by stage or grade in 49,934 male participants of the Health Professionals Follow-up Study. Multivariate adjusted hazard ratios (HR) and 95% confidence intervals (95% CI) were estimated using Cox proportional hazards regression.

RESULTS

Dietary GI, GL, II, or fiber was not associated with risk of total or subgroups of prostate cancer. We observed a positive association between dietary intake of whole grains and total prostate cancer (HR highest versus lowest quintile 1.13, 95% CI 1.03-1.24), which was attenuated after restriction to PSA-screened participants (HR 1.03, 95% CI 0.91-1.17).

CONCLUSIONS

These results suggest that long-term exposure to a diet with a high insulin response does not affect prostate cancer incidence.

Rye whole grain and bran intake compared with refined wheat decreases urinary C-peptide, plasma insulin, and prostate specific antigen in men with prostate cancer

Rye whole grain and bran intake has shown beneficial effects on prostate cancer progression in animal models, including lower tumor take rates, smaller tumor volumes, and reduced prostate specific antigen (PSA) concentrations. A human pilot study showed increased apoptosis after consumption of rye bran bread. In this study, we investigated the effect of high intake of rye whole grain and bran on prostate cancer progression as assessed by PSA concentration in men diagnosed with prostate cancer. Seventeen participants were provided with 485 g rye whole grain and bran products (RP) or refined wheat products with added cellulose (WP), corresponding to ~50% of daily energy intake, in a randomized controlled, crossover design. Blood samples were taken from fasting men before and after 2, 4, and 6 wk of treatment and 24-h urine samples were collected before the first intervention period and after treatment. Plasma total PSA concentrations were lower after treatment with RP compared with WP, with a mean treatment effect of -14% (P = 0.04). Additionally, fasting plasma insulin and 24-h urinary C-peptide excretion were lower after treatment with RP compared with WP (P < 0.01 and P = 0.01, respectively). Daily excretion of 5 lignans was higher after the RP treatment than after the WP treatment (P < 0.001). We conclude that whole grain and bran from rye resulted in significantly lower plasma PSA compared with a cellulose-supplemented refined wheat diet in patients with prostate cancer. The effect may be related to inhibition of prostate cancer progression caused by decreased exposure to insulin, as indicated by plasma insulin and urinary C-peptide excretion.