No effect of high eating frequency compared to low eating frequency on appetite and inflammation biomarkers: results from a randomized cross-over clinical trial

BACKGROUND

Eating frequency (EF) focuses on the total number of eating occasions per day and may influence metabolic health.

OBJECTIVE

We sought to examine the effect of high vs. low EF on appetite regulation and inflammatory biomarkers among healthy adults.

METHODS

Data are from a randomized, cross-over trial (the Frequency of Eating and Satiety Hormones (FRESH) Study). Participants (n=50) completed two isocaloric 21-day study periods of low EF (three eating occasions/day) and high EF (six eating occasions/day) in random order with a 14-day wash-out period in-between. Participants were free-living and consumed their own food, using study-directed, structured meal plans with identical foods and total energy in both study periods. On days 1 and 21 of each EF period, fasting blood was collected during in-person clinic visits to assess plasma concentrations of ghrelin, leptin, adiponectin, and high-sensitive C-reactive protein (hs-CRP). Linear mixed models with EF, diet order, and period as fixed effects; and participant as random effect estimated the intervention effect. Interaction effects between EF and % body fat were examined.

RESULTS

Among the 50 participants who completed the trial, 39 (78%) were women, 30 (60%) were Non-Hispanic White, 40 (80%) had a BMI<25 kg/m2, and the mean age was 32.1years. The differences between high vs. low EF in fasting ghrelin (geometric mean difference: 17.76 ng/ml, p=0.60), leptin (geometric mean difference: 2.09 ng/ml, p=0.14), adiponectin (geometric mean difference: 381.7 ng/ml, p=0.32), and hs-CRP (geometric mean difference: -0.018 mg/dl, p=0.08) were not statistically significant. No EF x % body fat interaction was observed on appetite regulation and inflammatory biomarkers.

CONCLUSIONS

No differences was observed in fasting ghrelin, leptin, adiponectin, and hs-CRP, comparing high vs. low EF. Future studies are needed to understand the physiology of eating frequency and appetite as they relate to metabolic health.

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

To examine associations between intakes of dietary fiber overall and by food source and risk of advanced and aggressive forms of PC.

DESIGN

Pooled analysis of the primary data in 15 cohorts in three continents. Baseline dietary fiber intake was assessed using a validated food frequency questionnaire or diet history in each study.

PARTICIPANTS/SETTING

842,149 men were followed for up to 9-22 years between 1985-2009 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), high grade (Gleason score ≥8 or poorly differentiated/undifferentiated) PC, and PC mortality.

STATISTICAL ANALYSIS

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=4,863), advanced restricted (n=2,978), or high-grade PC (n=9,673) or PC mortality (n=3,097). Dietary fiber intake from grains was inversely associated with advanced PC (MVHR comparing the highest vs. lowest quintile=0.84, 95% confidence interval [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≤0.03), while 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=0.002) for localized (n=35,199) and 1.05 (95%CI 0.99-1.11, , p-value, test for trend=0.04) for low/intermediate grade (n=34,366) PC.

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.

The Use of Three-Dimensional Images and Food Descriptions from a Smartphone Device Is Feasible and Accurate for Dietary Assessment

Technology-assisted dietary assessment has the potential to improve the accuracy of self-reported dietary intake. This study evaluates MealScan3D (MS3D), a mobile device-based food recording system, which uses three-dimensional images to obtain food volumes and an application to capture algorithm-driven food intake data. Participants (n = 179) were randomly assigned and trained to record three meals using either MS3D or a written food record (WFR). Generous amounts of standardized meals were provided, and participants self-selected portions for each food. The weights of provided and uneaten/leftover foods were used to determine true intake. For total energy intake (three meals combined), validity (Pearson correlation) was significantly higher for MS3D vs. the WFR (p < 0.001); when interpreted as the percentage of variance in energy intake explained, MS3D explained 84.6% of true variance, a 25.3% absolute and 42.6% relative increase over the 59.3% explained by the WFR. For 9 of 15 individual foods, the Pearson correlations between true and reported portion size estimates were significantly larger for MS3D than the WFR. Bias was smaller (intercepts were closer to the means) for 9 of 15 foods and the regression coefficients for 10 of 15 foods were significantly closer to 1.0 in the MS3D arm. MS3D is feasible for dietary assessment and may provide improvements in accuracy compared to WFRs.

Supplemental B-Vitamins and Risk of Upper Gastrointestinal Cancers in the Women's Health Initiative

B-vitamins contribute to DNA synthesis, maintenance, and regulation. Few studies have examined associations of supplemental sources of B-vitamins with the incidence of upper gastrointestinal (GI) cancers [including gastric (GCA) and esophageal (ECA) cancers]; the only prior study to comprehensively examine such intakes reported potential elevated risks of ECA. We examined 159,401 postmenopausal women, ages 50-79 years at baseline, including 302 incident GCA and 183 incident ECA cases, over 19 years of follow-up within the Women's Health Initiative observational study and clinic trials. Adjusted Cox regression models estimated hazard ratios (HR) and 95% confidence intervals (CI) for associations of supplemental B-vitamins [riboflavin (B2), pyridoxine (B6), folic acid (B9), or cobalamin (B12)] with GCA and ECA risk, respectively. Although HRs were generally below 1.0, we observed no statistically significant associations between supplemental intakes of any of the evaluated B-vitamins with the risk of GCA or ECA. As the first prospective study to comprehensively assess these associations, our findings do not corroborate prior research indicating potential harm from supplemental B-vitamin intake for upper GI cancer risk. This study adds evidence that supplemental intakes of B-vitamins may be used by postmenopausal women without regard to their relationship with upper GI cancer risk.

Circulating insulin-like growth factors and risks of overall, aggressive and early-onset prostate cancer: a collaborative analysis of 20 prospective studies and Mendelian randomization analysis

BACKGROUND

Previous studies had limited power to assess the associations of circulating insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) with clinically relevant prostate cancer as a primary endpoint, and the association of genetically predicted IGF-I with aggressive prostate cancer is not known. We aimed to investigate the associations of IGF-I, IGF-II, IGFBP-1, IGFBP-2 and IGFBP-3 concentrations with overall, aggressive and early-onset prostate cancer.

METHODS

Prospective analysis of biomarkers using the Endogenous Hormones, Nutritional Biomarkers and Prostate Cancer Collaborative Group dataset (up to 20 studies, 17 009 prostate cancer cases, including 2332 aggressive cases). Odds ratios (OR) and 95% confidence intervals (CI) for prostate cancer were estimated using conditional logistic regression. For IGF-I, two-sample Mendelian randomization (MR) analysis was undertaken using instruments identified using UK Biobank (158 444 men) and outcome data from PRACTICAL (up to 85 554 cases, including 15 167 aggressive cases). Additionally, we used colocalization to rule out confounding by linkage disequilibrium.

RESULTS

In observational analyses, IGF-I was positively associated with risks of overall (OR per 1 SD = 1.09: 95% CI 1.07, 1.11), aggressive (1.09: 1.03, 1.16) and possibly early-onset disease (1.11: 1.00, 1.24); associations were similar in MR analyses (OR per 1 SD = 1.07: 1.00, 1.15; 1.10: 1.01, 1.20; and 1.13; 0.98, 1.30, respectively). Colocalization also indicated a shared signal for IGF-I and prostate cancer (PP4: 99%). Men with higher IGF-II (1.06: 1.02, 1.11) and IGFBP-3 (1.08: 1.04, 1.11) had higher risks of overall prostate cancer, whereas higher IGFBP-1 was associated with a lower risk (0.95: 0.91, 0.99); these associations were attenuated following adjustment for IGF-I.

CONCLUSIONS

These findings support the role of IGF-I in the development of prostate cancer, including for aggressive disease.

Dietary Patterns and Risk of Gleason Grade Progression among Men on Active Surveillance for Prostate Cancer: Results from the Canary Prostate Active Surveillance Study

Modifiable lifestyle factors, such as following a healthy dietary pattern may delay or prevent prostate cancer (PCa) progression. However, few studies have evaluated whether following specific dietary patterns after PCa diagnosis impacts risk of disease progression among men with localized PCa managed by active surveillance (AS). 564 men enrolled in the Canary Prostate Active Surveillance Study, a protocol-driven AS study utilizing a pre-specified prostate-specific antigen monitoring and surveillance biopsy regimen, completed a food frequency questionnaire (FFQ) at enrollment and had ≥ 1 surveillance biopsy during follow-up. FFQs were used to evaluate adherence to the Dietary Guidelines for Americans (Healthy Eating index (HEI))-2015, alternative Mediterranean Diet (aMED), and Dietary Approaches to Stop Hypertension (DASH) dietary patterns. Multivariable-adjusted hazards ratios (HRs) and 95% confidence intervals were estimated using Cox proportional hazards models. During a median follow-up of 7.8 years, 237 men experienced an increase in Gleason score on subsequent biopsy (grade reclassification). Higher HEI-2015, aMED or DASH diet scores after diagnosis were not associated with significant reductions in the risk of grade reclassification during AS. However, these dietary patterns have well-established protective effects on chronic diseases and mortality and remain a prudent choice for men with prostate cancer managed by AS.

Circulating free testosterone and risk of aggressive prostate cancer: Prospective and Mendelian randomisation analyses in international consortia

Previous studies had limited power to assess the associations of testosterone with aggressive disease as a primary endpoint. Further, the association of genetically predicted testosterone with aggressive disease is not known. We investigated the associations of calculated free and measured total testosterone and sex hormone-binding globulin (SHBG) with aggressive, overall and early-onset prostate cancer. In blood-based analyses, odds ratios (OR) and 95% confidence intervals (CI) for prostate cancer were estimated using conditional logistic regression from prospective analysis of biomarker concentrations in the Endogenous Hormones, Nutritional Biomarkers and Prostate Cancer Collaborative Group (up to 25 studies, 14 944 cases and 36 752 controls, including 1870 aggressive prostate cancers). In Mendelian randomisation (MR) analyses, using instruments identified using UK Biobank (up to 194 453 men) and outcome data from PRACTICAL (up to 79 148 cases and 61 106 controls, including 15 167 aggressive cancers), ORs were estimated using the inverse-variance weighted method. Free testosterone was associated with aggressive disease in MR analyses (OR per 1 SD = 1.23, 95% CI = 1.08-1.40). In blood-based analyses there was no association with aggressive disease overall, but there was heterogeneity by age at blood collection (OR for men aged <60 years 1.14, CI = 1.02-1.28; Phet  = .0003: inverse association for older ages). Associations for free testosterone were positive for overall prostate cancer (MR: 1.20, 1.08-1.34; blood-based: 1.03, 1.01-1.05) and early-onset prostate cancer (MR: 1.37, 1.09-1.73; blood-based: 1.08, 0.98-1.19). SHBG and total testosterone were inversely associated with overall prostate cancer in blood-based analyses, with null associations in MR analysis. Our results support free testosterone, rather than total testosterone, in the development of prostate cancer, including aggressive subgroups.

Differential Biopsy Patterns Influence Associations Between Multivitamin Use and Prostate Cancer Risk in the Selenium and Vitamin E Cancer Prevention Trial

BACKGROUND

Multivitamin use is a common health behavior but there is conflicting evidence from prospective studies about whether this behavior increases or decreases prostate cancer (PCa) risk.

METHODS

Associations of multivitamin (MVI) use and PCa risk were evaluated using data from the Selenium and Vitamin E Cancer Prevention Trial (SELECT). Cox proportional hazards models estimated associations of MVI use with risk of total, low- and high-grade PCa. Longitudinal data were used to evaluate screening and biopsy patterns. To account for differential biopsy patterns, the probability of PCa was estimated for men with a positive screening value but no biopsy. Incidence Density Ratios were used to approximate hazards ratios, and associations of MVI use with predicted PCa risk were compared to observed.

RESULTS

Analyses of data from observed biopsies suggest a respective 19% (95% CI 10-28%) and 21% (12-31%) higher risk of high-grade PCa for current and long-term MVI use, compared to no use. Current and long-term MVI use was associated with a shorter time to first on-study biopsy, indicating the potential for detection bias. After accounting for differential acceptance of biopsy, associations of MVI use with PCa were attenuated and not statistically significant.

CONCLUSIONS

In SELECT, biopsy acceptance patterns differed by MVI use. Estimates of associations of MVI use with PCa risk based on observed biopsy data may be biased by differential acceptance of biopsy.

IMPACT

Differential biopsy ascertainment may impact associations of risk factors and PCa. Detailed screening and biopsy data can be used to analytically minimize such bias.

Treatment in the absence of disease reclassification among men on active surveillance for prostate cancer

BACKGROUND

Maintaining men on active surveillance for prostate cancer can be challenging. Although most men who eventually undergo treatment have experienced clinical progression, a smaller subset elects treatment in the absence of disease reclassification. This study sought to understand factors associated with treatment in a large, contemporary, prospective cohort.

METHODS

This study identified 1789 men in the Canary Prostate Cancer Active Surveillance Study cohort enrolled as of 2020 with a median follow-up of 5.6 years. Clinical and demographic data as well as information on patient-reported quality of life and urinary symptoms were used in multivariable Cox proportional hazards regression models to identify factors associated with the time to treatment RESULTS: Within 4 years of their diagnosis, 33% of men (95% confidence interval [CI], 30%-35%) underwent treatment, and 10% (95% CI, 9%-12%) were treated in the absence of reclassification. The most significant factor associated with any treatment was an increasing Gleason grade group (adjusted hazard ratio [aHR], 14.5; 95% CI, 11.7-17.9). Urinary quality-of-life scores were associated with treatment without reclassification (aHR comparing "mostly dissatisfied/terrible" with "pleased/mixed," 2.65; 95% CI, 1.54-4.59). In a subset analysis (n = 692), married men, compared with single men, were more likely to undergo treatment in the absence of reclassification (aHR, 2.63; 95% CI, 1.04-6.66).

CONCLUSIONS

A substantial number of men with prostate cancer undergo treatment in the absence of clinical changes in their cancers, and quality-of-life changes and marital status may be important factors in these decisions.

LAY SUMMARY

This analysis of men on active surveillance for prostate cancer shows that approximately 1 in 10 men will decide to be treated within 4 years of their diagnosis even if their cancer is stable. These choices may be related in part to quality-or-life or spousal concerns.

Association of Serum Carotenoids and Retinoids with Intraprostatic Inflammation in Men without Prostate Cancer or Clinical Indication for Biopsy in the Placebo Arm of the Prostate Cancer Prevention Trial

Non-supplemental carotenoids and retinol may potentiate antioxidant and anti-inflammatory mechanisms. Chronic intraprostatic inflammation is linked to prostate carcinogenesis. We investigated the association of circulating carotenoids and retinol with intraprostatic inflammation in benign tissue. We included 235 men from the Prostate Cancer Prevention Trial placebo arm who had a negative end-of-study biopsy, most (92.8%) done without clinical indication. α-carotene, β-carotene, β-cryptoxanthin, lycopene, and retinol were assessed by high-performance liquid chromatography using pooled year 1 and 4 serum. Presence and extent of intraprostatic inflammation in benign tissue was assessed in 3 (of 6-10) biopsy cores. Logistic (any core with inflammation vs none) and polytomous logistic (some or all cores with inflammation vs none) regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) of intraprostatic inflammation by concentration tertile adjusting for age, race, prostate cancer family history, and serum cholesterol. None of the carotenoids or retinol was associated with intraprostatic inflammation, except β-cryptoxanthin, which appeared to be positively associated with any core with inflammation [vs none, T2: OR (95% CI) = 2.67 (1.19, 5.99); T3: 1.80 (0.84, 3.82), P-trend = 0.12]. These findings suggest that common circulating carotenoids and retinol are not useful dietary intervention targets for preventing prostate cancer via modulating intraprostatic inflammation.

Feasibility of a behavioral intervention using mobile health applications to reduce cardiovascular risk factors in cancer survivors: a pilot randomized controlled trial

PURPOSE

Determine the feasibility of a remotely delivered mobile health (mHealth)-supported intervention to improve diet and physical activity in hematologic malignancy survivors.

METHODS

Pilot randomized controlled trial of a 16-week intervention for improving diet and physical activity: individualized goal-setting (daily steps, sodium, saturated fat, added sugar intake) per feedback from mHealth trackers (Fitbit for activity; Healthwatch360 for diet), supplemented by a Facebook peer support group. Controls accessed the trackers without goal-setting or peer support. Everyone received standardized survivorship counseling with tailored advice from a clinician. Actigraphy and food frequency questionnaires assessed activity and diet at baseline and follow-up.

RESULTS

Forty-one participants (51.2% male; median age 45.1 years; 7.0 years from treatment) were randomized (24 intervention; 17 control). Fitbit and Healthwatch360 use were more common among intervention versus control participants (75.0% versus 70.6% and 50.0% versus 17.7% of eligible days, respectively). Most intervention participants (66.7%) engaged with Facebook; overall, 91.7% interacted with the study's mHealth applications. While no comparisons in activity or dietary outcomes between intervention versus control group met statistical significance, the intervention was associated with greater reductions in the targeted dietary factors and improvements in Healthy Eating Index-2015 score, moderate-vigorous physical activity time, and daily steps. Participant retention at 6 months was 90.2%.

CONCLUSIONS

An intervention for cardiovascular risk reduction based on individualized goal-setting enhanced by mHealth and social media peer support was feasible and acceptable among cancer survivors.

IMPLICATIONS FOR CANCER SURVIVORS

Effective and easily disseminated strategies that improve diet and physical activity in this population are needed.

TRIAL REGISTRATION

Registered in ClinicalTrials.gov (NCT03574012) on June 29, 2018.

Abstract 4654: Supplemental one-carbon metabolism related B vitamins and lung cancer risk in the Women's Health Initiative

We and others have reported associations between B vitamins principally involved in one-carbon metabolism and increased lung cancer risk; however results for women have been inconsistent. Here we report on the association of supplemental vitamins B6, folic acid, and B12 intake and lung cancer risk using data from the Women's Health Initiative (WHI) study of postmenopausal women. Between 1993 and 1998, 161,808 women were recruited to participate in the WHI at 40 US clinical centers. After exclusions, 159,232 women were available for analysis and followed prospectively for 18.3 years. Among them, 3,836 incident lung cancer cases were diagnosed. At baseline, supplemental B vitamins from multivitamins, vitamin mixtures, and individual supplements were assessed. Adjusted Cox regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for associations between supplemental B vitamin intake and lung cancer risk. Relative to non-users, women who took ≥50 mg/d of vitamin B6 had 18% (HR 0.82, 95% CI: 0.70-0.97) reduced lung cancer risk. Associations did not differ significantly by smoking status or lung cancer histology. Intakes of folic acid and vitamin B12 were not associated with risk. There is a need for replication of our findings from large, prospective studies with high-quality measurement of supplement intakes. As such, no recommendation can be made at present on the use of B6 supplements for lung cancer prevention in women.

Citation Format: Theodore M. Brasky, Roberta M. Ray, Sandi L. Navarro, Jeannette M. Schenk, Alison M. Newton, Marian L. Neuhouser. Supplemental one-carbon metabolism related B vitamins and lung cancer risk in the Women's Health Initiative [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4654.

Vitamin D Pathway and Other Related Polymorphisms and Risk of Prostate Cancer: Results from the Prostate Cancer Prevention Trial

Vitamin D may influence prostate cancer risk, but evidence is inconsistent. We conducted a nested case-control study in the Prostate Cancer Prevention Trial (PCPT). Cases (n = 1,128) and controls (n = 1,205) were frequency matched on age, first-degree relative with prostate cancer, and PCPT treatment arm (finasteride/placebo); African-Americans were oversampled and case/control status was biopsy confirmed. We selected 21 SNPs in vitamin D-related genes (VDR, GC, C10orf88, CYP2R1, CYP24A1, CYP27B1, DHCR7, and NADSYN1) to test genotype and genotype-treatment interactions in relation to prostate cancer. We also tested mean serum 25(OH)D differences by minor allele distributions and tested for serum 25(OH)D-genotype interactions in relation to prostate cancer risk. Log-additive genetic models (Bonferroni-corrected within genes) adjusted for age, body mass index, PSA, and family history of prostate cancer revealed a significant interaction between treatment arm and GC/rs222016 (finasteride OR = 1.37, placebo OR = 0.85; P _interaction < 0.05), GC/rs222014 (finasteride OR = 1.36, placebo OR = 0.85; P _interaction < 0.05), and CYP27B1/rs703842 (finasteride OR = 0.76, placebo OR = 1.10; P _interaction < 0.05) among Caucasians, and C10orf88/rs6599638 (finasteride OR = 4.68, placebo OR = 1.39; P _interaction < 0.05) among African-Americans. VDR/rs1544410 and CYP27B1/rs703842 had significant treatment interactions for high-grade disease among Caucasians (finasteride OR = 0.81, placebo OR = 1.40; P _interaction < 0.05 and finasteride OR = 0.70, placebo OR = 1.28; P _interaction < 0.05, respectively). Vitamin D-related SNPs influenced serum 25(OH)D, but gene-serum 25(OH)D effect modification for prostate cancer was marginally observed only for CYP24A1/rs2248359. In conclusion, evidence that vitamin D-related genes or gene-serum 25(OH)D associations influence prostate cancer risk is modest. We found some evidence for gene-finasteride interaction effects for prostate cancer in Caucasians and African-Americans. Results suggest only minimal associations of vitamin D with total or high-grade prostate cancer.

Supplemental one-carbon metabolism related B vitamins and lung cancer risk in the Women's Health Initiative

We and others have reported associations between B vitamins principally involved in one-carbon metabolism and increased lung cancer risk; however, results for women have been inconsistent. Here we report on the association of supplemental vitamins B₆ , folic acid and B₁₂ intake and lung cancer risk using data from the Women's Health Initiative (WHI) study of postmenopausal women. Between 1993 and 1998, 161,808 women were recruited to participate in the WHI at 40 clinical centers in the US. After exclusions, 159,232 women were available for analysis and followed prospectively for an average of 18.3 years. Among them, 3,836 incident lung cancer cases were diagnosed. At baseline, supplemental B vitamins from multivitamins, vitamin mixtures and individual supplements were assessed. Adjusted Cox regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for associations between supplemental B vitamin intake and lung cancer risk. Relative to no intake, women who took ≥50 mg/day of vitamin B₆ had 16% (HR 0.84, 95% CI: 0.71-0.99) reduced lung cancer risk. Associations did not differ significantly by smoking status or lung cancer histology. Intakes of folic acid and vitamin B₁₂ were not associated with risk. There is a need for replication of our findings from other large, prospective studies with similar high-quality measurement of supplement intakes before any recommendations can be made at present on B₆ supplementation for lung cancer prevention in women.

Measures of body fatness and height in early and mid-to-late adulthood and prostate cancer: risk and mortality in The Pooling Project of Prospective Studies of Diet and Cancer

BACKGROUND

Advanced prostate cancer etiology is poorly understood. Few studies have examined associations of anthropometric factors (e.g. early adulthood obesity) with advanced prostate cancer risk.

PATIENTS AND METHODS

We carried out pooled analyses to examine associations between body fatness, height, and prostate cancer risk. Among 830 772 men, 51 734 incident prostate cancer cases were identified, including 4762 advanced (T4/N1/M1 or prostate cancer deaths) cases, 2915 advanced restricted (same as advanced, but excluding localized cancers that resulted in death) cases, 9489 high-grade cases, and 3027 prostate cancer deaths. Cox proportional hazards models were used to calculate study-specific hazard ratios (HR) and 95% confidence intervals (CI); results were pooled using random effects models.

RESULTS

No statistically significant associations were observed for body mass index (BMI) in early adulthood for advanced, advanced restricted, and high-grade prostate cancer, and prostate cancer mortality. Positive associations were shown for BMI at baseline with advanced prostate cancer (HR = 1.30, 95% CI = 0.95-1.78) and prostate cancer mortality (HR = 1.52, 95% CI = 1.12-2.07) comparing BMI ≥35.0 kg/m2 with 21-22.9 kg/m2. When considering early adulthood and baseline BMI together, a 27% higher prostate cancer mortality risk (95% CI = 9% to 49%) was observed for men with BMI <25.0 kg/m2 in early adulthood and BMI ≥30.0 kg/m2 at baseline compared with BMI <25.0 kg/m2 in early adulthood and BMI <30.0 kg/m2 at baseline. Baseline waist circumference, comparing ≥110 cm with <90 cm, and waist-to-hip ratio, comparing ≥1.00 with <0.90, were associated with significant 14%-16% increases in high-grade prostate cancer risk and suggestive or significant 20%-39% increases in prostate cancer mortality risk. Height was associated with suggestive or significant 33%-56% risks of advanced or advanced restricted prostate cancer and prostate cancer mortality, comparing ≥1.90 m with <1.65 m.

CONCLUSION

Our findings suggest that height and total and central adiposity in mid-to-later adulthood, but not early adulthood adiposity, are associated with risk of advanced forms of prostate cancer. Thus, maintenance of healthy weight may help prevent advanced prostate cancer.

The associations of anthropometric, behavioural and sociodemographic factors with circulating concentrations of IGF-I, IGF-II, IGFBP-1, IGFBP-2 and IGFBP-3 in a pooled analysis of 16,024 men from 22 studies

Insulin-like growth factors (IGFs) and insulin-like growth factor binding proteins (IGFBPs) have been implicated in the aetiology of several cancers. To better understand whether anthropometric, behavioural and sociodemographic factors may play a role in cancer risk via IGF signalling, we examined the cross-sectional associations of these exposures with circulating concentrations of IGFs (IGF-I and IGF-II) and IGFBPs (IGFBP-1, IGFBP-2 and IGFBP-3). The Endogenous Hormones, Nutritional Biomarkers and Prostate Cancer Collaborative Group dataset includes individual participant data from 16,024 male controls (i.e. without prostate cancer) aged 22-89 years from 22 prospective studies. Geometric means of protein concentrations were estimated using analysis of variance, adjusted for relevant covariates. Older age was associated with higher concentrations of IGFBP-1 and IGFBP-2 and lower concentrations of IGF-I, IGF-II and IGFBP-3. Higher body mass index was associated with lower concentrations of IGFBP-1 and IGFBP-2. Taller height was associated with higher concentrations of IGF-I and IGFBP-3 and lower concentrations of IGFBP-1. Smokers had higher concentrations of IGFBP-1 and IGFBP-2 and lower concentrations of IGFBP-3 than nonsmokers. Higher alcohol consumption was associated with higher concentrations of IGF-II and lower concentrations of IGF-I and IGFBP-2. African Americans had lower concentrations of IGF-II, IGFBP-1, IGFBP-2 and IGFBP-3 and Hispanics had lower IGF-I, IGF-II and IGFBP-3 than non-Hispanic whites. These findings indicate that a range of anthropometric, behavioural and sociodemographic factors are associated with circulating concentrations of IGFs and IGFBPs in men, which will lead to a greater understanding of the mechanisms through which these factors influence cancer risk.

Randomized trial evaluating the role of weight loss in overweight and obese men with early stage prostate Cancer on active surveillance: Rationale and design of the Prostate Cancer Active Lifestyle Study (PALS)

Active surveillance (AS) is increasingly used to monitor patients with low-risk prostate cancer; however, approximately 50% of AS patients experience disease reclassification requiring definitive treatment and little is known about patient characteristics that modify the risk of reclassification. Obesity may be one of the major contributing factors. The Prostate Cancer Active Lifestyle Study (PALS) is a clinical trial evaluating the impact of weight loss among overweight/obese (Body Mass Index (BMI) ≥ 25 kg/m2) men with clinically localized prostate cancer on AS. Two hundred participants will be randomized to either the PALS intervention, a 6-month structured diet and exercise program adapted from the Diabetes Prevention Program followed by 6 months of maintenance, or control (general diet and physical activity guidelines delivered in a single session). The PALS intervention involves one-on-one instruction with a registered dietitian and exercise physiologist to achieve the study goal of loss of 7% of baseline weight. Participation is coordinated so that the 6-month time point coincides with the participants' standard-of-care AS prostate biopsy. Primary outcomes will evaluate the intervention effects on circulating and tissue markers of glucose and insulin regulation, health-related quality of life and pathologic upgrading on follow-up prostate biopsies. Additional analyses will determine whether changes in weight and glucose regulation can be sustained for 6 months after the end of instruction. Findings from this trial may have wide reaching implications for men diagnosed with clinically-localized prostate cancer by providing an active lifestyle-based approach to improve prostate cancer patient outcomes.

A Collaborative Analysis of Individual Participant Data from 19 Prospective Studies Assesses Circulating Vitamin D and Prostate Cancer Risk

Previous prospective studies assessing the relationship between circulating concentrations of vitamin D and prostate cancer risk have shown inconclusive results, particularly for risk of aggressive disease. In this study, we examine the association between prediagnostic concentrations of 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)2D] and the risk of prostate cancer overall and by tumor characteristics. Principal investigators of 19 prospective studies provided individual participant data on circulating 25(OH)D and 1,25(OH)2D for up to 13,462 men with incident prostate cancer and 20,261 control participants. ORs for prostate cancer by study-specific fifths of season-standardized vitamin D concentration were estimated using multivariable-adjusted conditional logistic regression. 25(OH)D concentration was positively associated with risk for total prostate cancer (multivariable-adjusted OR comparing highest vs. lowest study-specific fifth was 1.22; 95% confidence interval, 1.13-1.31; P trend < 0.001). However, this association varied by disease aggressiveness (P heterogeneity = 0.014); higher circulating 25(OH)D was associated with a higher risk of nonaggressive disease (OR per 80 percentile increase = 1.24, 1.13-1.36) but not with aggressive disease (defined as stage 4, metastases, or prostate cancer death, 0.95, 0.78-1.15). 1,25(OH)2D concentration was not associated with risk for prostate cancer overall or by tumor characteristics. The absence of an association of vitamin D with aggressive disease does not support the hypothesis that vitamin D deficiency increases prostate cancer risk. Rather, the association of high circulating 25(OH)D concentration with a higher risk of nonaggressive prostate cancer may be influenced by detection bias. SIGNIFICANCE: This international collaboration comprises the largest prospective study on blood vitamin D and prostate cancer risk and shows no association with aggressive disease but some evidence of a higher risk of nonaggressive disease.

Comparison of Nutrient Estimates Based on Food Volume versus Weight: Implications for Dietary Assessment Methods

Novel technology-based dietary assessment methods use volume estimates of foods to assess dietary intake. However, the nutrient content of standard databases is based on food weight. The goal of this study is to evaluate the accuracy of the United States Department of Agriculture National Nutrient Database for Standard Reference (USDA-SR) estimates of volume and the corresponding macronutrient content of the foods. The weights of 35 individual food volumes were measured (on trial) and compared to the USDA-SR-determined weight for the food volume. Macronutrient content corresponding to the trial weight and the USDA-SR weight for the food volume (USDA) were determined using the USDA-SR, and the differences were calculated. There were statistically significant differences between the USDA and trial weights for 80% of foods measured. Calorie estimates by USDA weight were significantly lower than that of trial weight for 54% of foods but were significantly greater for 26% of foods. Differences in macronutrient estimates by trial and USDA weight varied by food type. These findings suggest that nutrient databases based on food weight may not provide accurate estimates of dietary intake when assessed using food volumes. Further development of image-assisted dietary assessment methods which measure food volumes will necessitate evaluation of the accuracy of the processes used to convert weight to volume in nutrient databases.

Circulating sex hormones in relation to anthropometric, sociodemographic and behavioural factors in an international dataset of 12,300 men

INTRODUCTION

Sex hormones have been implicated in the etiology of a number of diseases. To better understand disease etiology and the mechanisms of disease-risk factor associations, this analysis aimed to investigate the associations of anthropometric, sociodemographic and behavioural factors with a range of circulating sex hormones and sex hormone-binding globulin.

METHODS

Statistical analyses of individual participant data from 12,330 male controls aged 25-85 years from 25 studies involved in the Endogenous Hormones Nutritional Biomarkers and Prostate Cancer Collaborative Group. Analysis of variance was used to estimate geometric means adjusted for study and relevant covariates.

RESULTS

Older age was associated with higher concentrations of sex hormone-binding globulin and dihydrotestosterone and lower concentrations of dehydroepiandrosterone sulfate, free testosterone, androstenedione, androstanediol glucuronide and free estradiol. Higher body mass index was associated with higher concentrations of free estradiol, androstanediol glucuronide, estradiol and estrone and lower concentrations of dihydrotestosterone, testosterone, sex hormone-binding globulin, free testosterone, androstenedione and dehydroepiandrosterone sulfate. Taller height was associated with lower concentrations of androstenedione, testosterone, free testosterone and sex hormone-binding globulin and higher concentrations of androstanediol glucuronide. Current smoking was associated with higher concentrations of androstenedione, sex hormone-binding globulin and testosterone. Alcohol consumption was associated with higher concentrations of dehydroepiandrosterone sulfate, androstenedione and androstanediol glucuronide. East Asians had lower concentrations of androstanediol glucuronide and African Americans had higher concentrations of estrogens. Education and marital status were modestly associated with a small number of hormones.

CONCLUSION

Circulating sex hormones in men are strongly associated with age and body mass index, and to a lesser extent with smoking status and alcohol consumption.

Plasma Fatty Acids as Surrogate for Prostate Levels

Inconsistent results from epidemiologic studies of circulating fatty acids and prostate cancer risk may be partly due to use of blood concentrations as surrogate biomarkers of prostate tissue concentrations. To determine whether blood concentrations reflect prostate tissue fatty acid profiles, we evaluated associations between phospholipid fatty acid (PLFA) profiles measured in plasma and prostate tissue from 20 patients who underwent prostatectomy. For each patient, three prostate tissue specimens varying in size and location were collected. Correlations were calculated between a) tissue specimens by size ( ≤ 20 mg, > 20 mg); b) individual tissue samples [Intraclass Correlation Coefficient (ICC)]; and c) plasma and mean tissue PLFA concentrations. PLFA concentrations from ≤ 20 mg and > 20 mg tissues were nearly identical. For most PLFAs, intra-individual correlations between tissue specimens were moderate to strong (linoleic acid = 0.66, eicosapentaenoic acid = 0.96), with only one ICC below 0.50 (trans-fatty acid 18:2, ICC = 0.28). Most correlations of mean tissue and plasma concentrations were moderate to strong (α-linoleic acid = 0.47, eicosapentaenoic acid = 0.93). PLFA concentrations are largely homogeneous within the prostate and can be reliably measured in small quantities of tissue. The overall strong correlations between plasma and tissue suggest that for most individual PLFAs, plasma concentrations are adequate surrogate markers of prostate tissue concentrations.

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.

The feasibility, usability, and clinical utility of traditional paper food and symptom journals for patients with irritable bowel syndrome

BACKGROUND

Paper food and gastrointestinal (GI) symptom journals are used to help irritable bowel syndrome (IBS) patients determine potential trigger foods. The primary aim of this study was to evaluate the feasibility, usability, and clinical utility of such journals as a data collection tool. A secondary aim was to explore a method for analyzing journal data to describe patterns of diet and symptoms.

METHODS

Participants (N=17) were asked to log three sets of 3-day food and symptom journals over a 15-day period. Feasibility was evaluated by journal completion rates, symptom logging compliance, and logging fatigability. The feasibility, usability, and clinical utility of journaling were also assessed by a customized evaluation and exit interview. For each journal, regression analyses were conducted to examine relationships between key meal nutrients and subsequent symptoms.

KEY RESULTS

Most participants were young (mean age 35±12) Caucasian (N=13) women (N=14). Journal completion rates were 100% for all participants with no logging fatigability. Over half perceived paper journaling of food and symptoms as feasible, usable, and clinically useful. Thirteen participants demonstrated a strong association with at least one symptom and meal nutrient. Patterns of associations differed among participants.

CONCLUSIONS AND INFERENCES

Paper journaling of food and GI symptoms for 9 days over a 15-day period appeared to be a feasible and usable data collection tool for IBS patients. Over half perceived journaling as at least somewhat clinically useful. Findings from this study support the anecdote that food trigger(s) and associated symptom(s) vary for each individual.

Selenium and Prostate Cancer: Analysis of Individual Participant Data From Fifteen Prospective Studies

BACKGROUND

Some observational studies suggest that a higher selenium status is associated with a lower risk of prostate cancer but have been generally too small to provide precise estimates of associations, particularly by disease stage and grade.

METHODS

Collaborating investigators from 15 prospective studies provided individual-participant records (from predominantly men of white European ancestry) on blood or toenail selenium concentrations and prostate cancer risk. Odds ratios of prostate cancer by selenium concentration were estimated using multivariable-adjusted conditional logistic regression. All statistical tests were two-sided.

RESULTS

Blood selenium was not associated with the risk of total prostate cancer (multivariable-adjusted odds ratio [OR] per 80 percentile increase = 1.01, 95% confidence interval [CI] = 0.83 to 1.23, based on 4527 case patients and 6021 control subjects). However, there was heterogeneity by disease aggressiveness (ie, advanced stage and/or prostate cancer death, Pheterogeneity = .01), with high blood selenium associated with a lower risk of aggressive disease (OR = 0.43, 95% CI = 0.21 to 0.87) but not with nonaggressive disease. Nail selenium was inversely associated with total prostate cancer (OR = 0.29, 95% CI = 0.22 to 0.40, Ptrend < .001, based on 1970 case patients and 2086 control subjects), including both nonaggressive (OR = 0.33, 95% CI = 0.22 to 0.50) and aggressive disease (OR = 0.18, 95% CI = 0.11 to 0.31, Pheterogeneity = .08).

CONCLUSIONS

Nail, but not blood, selenium concentration is inversely associated with risk of total prostate cancer, possibly because nails are a more reliable marker of long-term selenium exposure. Both blood and nail selenium concentrations are associated with a reduced risk of aggressive disease, which warrants further investigation.

Changes in relative and absolute concentrations of plasma phospholipid fatty acids observed in a randomized trial of Omega-3 fatty acids supplementation in Uganda

Expressing circulating phospholipid fatty acids (PLFAs) in relative concentrations has some limitations: the total of all fatty acids are summed to 100%; therefore, the values of individual fatty acid are not independent. In this study we examined if both relative and absolute metrics could effectively measure changes in circulating PLFA concentrations in an intervention trial. 66 HIV and HHV8 infected patients in Uganda were randomized to take 3g/d of either long-chain omega-3 fatty acids (1856mg EPA and 1232mg DHA) or high-oleic safflower oil in a 12-week double-blind trial. Plasma samples were collected at baseline and end of trial. Relative weight percentage and absolute concentrations of 41 plasma PLFAs were measured using gas chromatography. Total cholesterol was also measured. Intervention-effect changes in concentrations were calculated as differences between end of 12-week trial and baseline. Pearson correlations of relative and absolute concentration changes in individual PLFAs were high (>0.6) for 37 of the 41 PLFAs analyzed. In the intervention arm, 17 PLFAs changed significantly in relative concentration and 16 in absolute concentration, 15 of which were identical. Absolute concentration of total PLFAs decreased 95.1mg/L (95% CI: 26.0, 164.2; P=0.0085), but total cholesterol did not change significantly in the intervention arm. No significant change was observed in any of the measurements in the placebo arm. Both relative weight percentage and absolute concentrations could effectively measure changes in plasma PLFA concentrations. EPA and DHA supplementation changes the concentrations of multiple plasma PLFAs besides EPA and DHA.Both relative weight percentage and absolute concentrations could effectively measure changes in plasma phospholipid fatty acid (PLFA) concentrations.

Biases in Recommendations for and Acceptance of Prostate Biopsy Significantly Affect Assessment of Prostate Cancer Risk Factors: Results From Two Large Randomized Clinical Trials

Purpose To identify factors related to who undergoes a prostate biopsy in a screened population and to estimate the impact of biopsy verification on risk factor-prostate cancer associations. Patients and Methods Men who were screened regularly from the placebo arms of two large prostate cancer prevention trials (Prostate Cancer Prevention Trial [PCPT] and Selenium and Vitamin E Cancer Prevention Trial [SELECT]) were examined to define incident prostate cancer cohorts. Because PCPT had an end-of-study biopsy, prostate cancer cases were categorized by a preceding prostate-specific antigen/digital rectal examination prompt (yes/no) and noncases by biopsy-proven negative status (yes v no). We estimated the association of risk factors (age, ethnicity, family history, body mass index, medication use) with prostate cancer and quantified differences in risk associations across cohorts. Results Men 60 to 69 years of age, those with benign prostatic hyperplasia, and those with a family history of prostate cancer were more likely, and those with a higher body mass index (≥ 25), diabetes, or a smoking history were less likely, to undergo biopsy, adjusting for age and longitudinal prostate-specific antigen and digital rectal examination. Medication use, education, and marital status also influenced who underwent biopsy. Some risk factor estimates for prostate cancer varied substantially across cohorts. Black ( v other ethnicities) had odds ratios (ORs) that varied from 1.20 for SELECT (community screening standards, epidemiologic-like cohort) to 1.83 for PCPT (end-of-study biopsy supplemented with imputed end points). Statin use in SELECT provided an OR of 0.65 and statin use in in PCPT provided an OR of 0.99, a relative difference of 34%. Conclusion Among screened men enrolled in prostate cancer prevention trials, differences in risk factor estimates for prostate cancer likely underestimate the magnitude of bias found in other cohorts with varying screening and biopsy recommendations and acceptance. Risk factors for prostate cancer derived from epidemiologic studies not only may be erroneous but may lead to misdirected research efforts.

A diagnosis of prostate cancer and pursuit of active surveillance is not followed by weight loss: potential for a teachable moment

BACKGROUND

Obesity is a risk factor for incident prostate cancer (PC) as well as risk of disease progression and mortality. We hypothesized that men diagnosed with lower-risk PC and who elected active surveillance (AS) for their cancer management would likely initiate lifestyle changes that lead to weight loss.

METHODS

Patients were enrolled in the Prostate Active Surveillance Study (PASS), a multicenter prospective biomarker discovery and validation study of men who have chosen AS for their PC. Data from 442 men diagnosed with PC within 1 year of study entry who completed a standard of care 12-month follow-up visit were analyzed. We examined the change in weight and body mass index (BMI) over the first year of study participation.

RESULTS

After 1 year on AS, 7.5% (33/442) of patients had lost 5% or more of their on-study weight. The proportion of men who lost 5% or more weight was similar across categories of baseline BMI: normal/underweight (8%), overweight (6%) and obese (10%, χ² test P=0.44). The results were similar for patients enrolled in the study 1 year or 6 months after diagnosis. By contrast, after 1 year, 7.7% (34/442) of patients had gained >5% of their weight.

CONCLUSIONS

Only 7.5% of men with low-risk PC enrolled in AS lost a modest (⩾5%) amount of weight after diagnosis. Given that obesity is related to PC progression and mortality, targeted lifestyle interventions may be effective at this 'teachable moment', as men begin AS for low-risk PC.

Measurement of Circulating Phospholipid Fatty Acids: Association between Relative Weight Percentage and Absolute Concentrations

OBJECTIVE

Most epidemiologic studies of circulating phospholipid fatty acids (PLFAs) and disease risk have used the relative concentration (percentage of total) of each fatty acid as the measure of exposure. Using relative concentrations, the total of all fatty acids is summed to 100% and thus the values of individual fatty acid are not independent. This has led to debate, along with the suggestion to use absolute concentrations of fatty acids. We aimed to examine the relationship between relative (weight percentage) and absolute (mg/L) concentrations of individual circulating PLFAs.

METHODS

Relative and absolute concentrations of 41 circulating PLFAs were measured by gas chromatography in samples from 3 diverse populations. Correlations between the relative and absolute concentrations for each fatty acid were used to measure agreement. Unadjusted correlations and correlations adjusting absolute PLFA concentrations for total cholesterol were calculated.

RESULTS

Unadjusted correlations between relative and absolute concentrations, as well as correlations adjusting absolute PLFA concentrations for total cholesterol, were high for most PLFAs in all 3 studies. Across the 3 studies, 28 of the 41 analyzed PLFAs had unadjusted correlations > 0.6 and 39 had adjusted correlations > 0.6.

CONCLUSIONS

Choice of relative vs absolute concentration may not affect interpretation of results for most circulating PLFAs in studies of association between individual PLFAs and disease outcomes, especially if a covariate reflecting total lipids, such as total circulating cholesterol, is included in the model. However, for fatty acids, such as 16:0 (palmitic acid), with low correlation between the 2 metrics, using relative vs absolute concentration may lead to different inferences regarding their association with the outcome. Because both concentrations could be obtained simultaneously from the same laboratory assay, use of both metrics is warranted to better understand PLFA-disease relationships.

Associations between unprocessed red and processed meat, poultry, seafood and egg intake and the risk of prostate cancer: A pooled analysis of 15 prospective cohort studies

Reports relating meat intake to prostate cancer risk are inconsistent. Associations between these dietary factors and prostate cancer were examined in a consortium of 15 cohort studies. During follow-up, 52,683 incident prostate cancer cases, including 4,924 advanced cases, were identified among 842,149 men. Cox proportional hazard models were used to calculate study-specific relative risks (RR) and then pooled using random effects models. Results do not support a substantial effect of total red, unprocessed red and processed meat for all prostate cancer outcomes, except for a modest positive association for tumors identified as advanced stage at diagnosis (advanced(r)). For seafood, no substantial effect was observed for prostate cancer regardless of stage or grade. Poultry intake was inversely associated with risk of advanced and fatal cancers (pooled multivariable RR [MVRR], 95% confidence interval, comparing ≥ 45 vs. <5 g/day: advanced 0.83, 0.70-0.99; trend test p value 0.29), fatal, 0.69, 0.59-0.82, trend test p value 0.16). Participants who ate ≥ 25 versus <5 g/day of eggs (1 egg ∼ 50 g) had a significant 14% increased risk of advanced and fatal cancers (advanced 1.14, 1.01-1.28, trend test p value 0.01; fatal 1.14, 1.00-1.30, trend test p value 0.01). When associations were analyzed separately by geographical region (North America vs. other continents), positive associations between unprocessed red meat and egg intake, and inverse associations between poultry intake and advanced, advanced(r) and fatal cancers were limited to North American studies. However, differences were only statistically significant for eggs. Observed differences in associations by geographical region warrant further investigation.

Association of androgen metabolism gene polymorphisms with prostate cancer risk and androgen concentrations: Results from the Prostate Cancer Prevention Trial

BACKGROUND

Prostate cancer is highly influenced by androgens and genes. The authors investigated whether genetic polymorphisms along the androgen biosynthesis and metabolism pathways are associated with androgen concentrations or with the risk of prostate cancer or high-grade disease from finasteride treatment.

METHODS

A nested case-control study from the Prostate Cancer Prevention Trial using data from men who had biopsy-proven prostate cancer (cases) and a group of biopsy-negative, frequency-matched controls was conducted to investigate the association of 51 single nucleotide polymorphisms (SNPs) in 12 genes of the androgen pathway with overall (total), low-grade, and high-grade prostate cancer incidence and serum hormone concentrations.

RESULTS

There were significant associations of genetic polymorphisms in steroid 5α-reductase 1 (SRD5A1) (reference SNPs: rs3736316, rs3822430, rs1560149, rs248797, and rs472402) and SRD5A2 (rs2300700) with the risk of high-grade prostate cancer in the placebo arm of the Prostate Cancer Prevention Trial; 2 SNPs were significantly associated with an increased risk (SRD5A1 rs472402 [odds ratio, 1.70; 95% confidence interval, 1.05-2.75; Ptrend = .03] and SRD5A2 rs2300700 [odds ratio, 1.94; 95% confidence interval, 1.19-3.18; Ptrend = .01]). Eleven SNPs in SRD5A1, SRD5A2, cytochrome P450 family 1, subfamily B, polypeptide 1 (CYP1B1), and CYP3A4 were associated with modifying the mean concentrations of serum androgen and sex hormone-binding globulin; and 2 SNPs (SRD5A1 rs824811 and CYP1B1 rs10012; Ptrend < .05) consistently and significantly altered all androgen concentrations. Several SNPs (SRD5A1 rs3822430, SRD5A2 rs2300700, CYP3A43 rs800672, and CYP19 rs700519; Ptrend < .05) were significantly associated with both circulating hormone levels and prostate cancer risk.

CONCLUSIONS

Germline genetic variations of androgen-related pathway genes are associated with serum androgen concentrations and the risk of prostate cancer. Further studies to examine the functional consequence of novel causal variants are warranted. Cancer 2016;122:2332-2340. © 2016 American Cancer Society.

A Meta-analysis of Individual Participant Data Reveals an Association between Circulating Levels of IGF-I and Prostate Cancer Risk

The role of insulin-like growth factors (IGF) in prostate cancer development is not fully understood. To investigate the association between circulating concentrations of IGFs (IGF-I, IGF-II, IGFBP-1, IGFBP-2, and IGFBP-3) and prostate cancer risk, we pooled individual participant data from 17 prospective and two cross-sectional studies, including up to 10,554 prostate cancer cases and 13,618 control participants. Conditional logistic regression was used to estimate the ORs for prostate cancer based on the study-specific fifth of each analyte. Overall, IGF-I, IGF-II, IGFBP-2, and IGFBP-3 concentrations were positively associated with prostate cancer risk (Ptrend all ≤ 0.005), and IGFBP-1 was inversely associated weakly with risk (Ptrend = 0.05). However, heterogeneity between the prospective and cross-sectional studies was evident (Pheterogeneity = 0.03), unless the analyses were restricted to prospective studies (with the exception of IGF-II, Pheterogeneity = 0.02). For prospective studies, the OR for men in the highest versus the lowest fifth of each analyte was 1.29 (95% confidence interval, 1.16-1.43) for IGF-I, 0.81 (0.68-0.96) for IGFBP-1, and 1.25 (1.12-1.40) for IGFBP-3. These associations did not differ significantly by time-to-diagnosis or tumor stage or grade. After mutual adjustment for each of the other analytes, only IGF-I remained associated with risk. Our collaborative study represents the largest pooled analysis of the relationship between prostate cancer risk and circulating concentrations of IGF-I, providing strong evidence that IGF-I is highly likely to be involved in prostate cancer development. Cancer Res; 76(8); 2288-300. ©2016 AACR.

Difference in Association of Obesity With Prostate Cancer Risk Between US African American and Non-Hispanic White Men in the Selenium and Vitamin E Cancer Prevention Trial (SELECT)

IMPORTANCE

African American men have the highest rates of prostate cancer incidence and mortality in the United States. Understanding underlying reasons for this disparity could identify preventive interventions important to African American men.

OBJECTIVE

To determine whether the association of obesity with prostate cancer risk differs between African American and non-Hispanic white men and whether obesity modifies the excess risk associated with African American race.

DESIGN, SETTING, AND PARTICIPANTS

Prospective study of 3398 African American and 22,673 non-Hispanic white men who participated in the Selenium and Vitamin E Cancer Prevention Trial (2001-2011) with present analyses completed in 2014.

MAIN OUTCOMES AND MEASURES

Total, low-grade (Gleason score <7), and high-grade (Gleason score ≥7) prostate cancer incidence.

RESULTS

With a median (interquartile range) follow-up of 5.6 (1.8) years, there were 270, 148, and 88 cases of total, low-, and high-grade prostate cancers among African American men and a corresponding 1453, 898, and 441 cases in non-Hispanic white men, respectively. Although not associated with risk among non-Hispanic white men, BMI was positively associated with an increase in risk among African American men (BMI, <25 vs ≥35: hazard ratio [HR], 1.49 [95% CI, 0.95, 2.34]; P for trend = .03). Consequently, the risk associated with African American race increased from 28% (HR, 1.28 [95% CI, 0.91-1.80]) among men with BMI less than 25 to 103% (HR, 2.03 [95% CI, 1.38-2.98]) among African American men with BMI at least 35 (P for trend = .03). Body mass index was inversely associated with low-grade prostate cancer risk within non-Hispanic white men (BMI, <25 vs ≥35: HR, 0.80 [95% CI, 0.58-1.09]; P for trend = .02) but positively associated with risk within African American men (BMI, <25 vs ≥35: HR, 2.22 [95% CI, 1.17-4.21]; P for trend = .05). Body mass index was positively associated with risk of high-grade prostate cancer in both non-Hispanic white men (BMI, <25 vs ≥35: HR, 1.33 [95% CI, 0.90-1.97]; P for trend = .01) and African American men, although the increase may be larger within African American men, albeit the racial interaction was not statistically significant (BMI, <25 vs ≥35: HR, 1.81 [95% CI, 0.79-4.11]; P for trend = .02).

CONCLUSIONS AND RELEVANCE

Obesity is more strongly associated with increased prostate cancer risk among African American than non-Hispanic white men and reducing obesity among African American men could reduce the racial disparity in cancer incidence. Additional research is needed to elucidate the mechanisms underlying the differential effects of obesity in African American and non-Hispanic white men.

Serum androgens and prostate cancer risk: results from the placebo arm of the Prostate Cancer Prevention Trial

BACKGROUND

Compelling and long-standing data suggest that androgens play an important role in the development of both normal prostate epithelium and prostate cancer. Although testosterone administration can induce prostate cancer (PCA) in laboratory animals, serum-based epidemiologic studies examining androgens in humans have not consistently supported a role for androgens in prostate carcinogenesis. We examined whether pre-diagnostic serum androgens were associated with PCA risk in the placebo arm of the Prostate Cancer Prevention Trial.

METHODS

In this nested case-control study, cases (n = 1,032) were primarily local-stage, biopsy-detected cancers, and controls (n = 1,025) were biopsy-confirmed to be PCA-free. Pre-diagnostic serum androgens (total testosterone, 3α-androstanediol glucuronide, free testosterone), estrogen-to-testosterone ratio, and sex hormone-binding globulin (SHBG) concentrations were measured in pooled (baseline and year 3) blood samples.

RESULTS

We found no significant associations between serum androgens, estrogen-to-testosterone ratios, or SHBG and risk of total, low (Gleason <7) or high-grade (Gleason 7-10) PCA.

CONCLUSION

Much remains to be learned about the role of androgens in prostate carcinogenesis. Further research is needed to evaluate the role of androgens, timing of exposure, genetic modulators of androgen metabolism, or environmental exposures that may affect androgen influence on prostate carcinogenesis.

Carotenoids, retinol, tocopherols, and prostate cancer risk: pooled analysis of 15 studies

BACKGROUND

Individual studies have suggested that circulating carotenoids, retinol, or tocopherols may be associated with prostate cancer risk, but the studies have not been large enough to provide precise estimates of associations, particularly by stage and grade of disease.

OBJECTIVE

The objective of this study was to conduct a pooled analysis of the associations of the concentrations of 7 carotenoids, retinol, α-tocopherol, and γ-tocopherol with risk of prostate cancer and to describe whether any associations differ by stage or grade of the disease or other factors.

DESIGN

Principal investigators of prospective studies provided individual participant data for prostate cancer cases and controls. Risk by study-specific fifths of each biomarker was estimated by using multivariable-adjusted conditional logistic regression in matched case-control sets.

RESULTS

Data were available for up to 11,239 cases (including 1654 advanced stage and 1741 aggressive) and 18,541 controls from 15 studies. Lycopene was not associated with overall risk of prostate cancer, but there was statistically significant heterogeneity by stage of disease, and the OR for aggressive disease for the highest compared with the lowest fifth of lycopene was 0.65 (95% CI: 0.46, 0.91; P-trend = 0.032). No other carotenoid was significantly associated with overall risk of prostate cancer or with risk of advanced-stage or aggressive disease. For retinol, the OR for the highest compared with the lowest fifth was 1.13 (95% CI: 1.04, 1.22; P-trend = 0.015). For α-tocopherol, the OR for the highest compared with the lowest fifth was 0.86 (95% CI: 0.78, 0.94; P-trend < 0.001), with significant heterogeneity by stage of disease; the OR for aggressive prostate cancer was 0.74 (95% CI: 0.59, 0.92; P-trend = 0.001). γ-Tocopherol was not associated with risk.

CONCLUSIONS

Overall prostate cancer risk was positively associated with retinol and inversely associated with α-tocopherol, and risk of aggressive prostate cancer was inversely associated with lycopene and α-tocopherol. Whether these associations reflect causal relations is unclear.

Non-steroidal anti-inflammatory drug (NSAID) use is not associated with erectile dysfunction risk: results from the Prostate Cancer Prevention Trial

OBJECTIVE

To evaluate the associations of non-steroidal anti-inflammatory drug (NSAID) use with risk of erectile dysfunction (ED), considering the indications for NSAID use.

PATIENTS AND METHODS

We analysed data from 4 726 men in the placebo arm of the Prostate Cancer Prevention Trial (PCPT) without evidence of ED at baseline. Incident ED was defined as mild/moderate (decrease in normal function) or severe (absence of function). Proportional hazards models were used to estimate the covariate-adjusted associations of NSAID-related medical conditions and time-dependent NSAID use with ED risk.

RESULTS

Arthritis (hazard ratio [HR] 1.56), chronic musculoskeletal pain (HR 1.35), general musculoskeletal complaints (HR 1.36), headaches (HR 1.44), sciatica (HR 1.50) and atherosclerotic disease (HR 1.60) were all significantly associated with an increased risk of mild/moderate ED, while only general musculoskeletal complaints (HR 1.22), headaches (HR 1.47) and atherosclerotic disease (HR 1.60) were associated with an increased risk of severe ED. Non-aspirin NSAID use was associated with an increased risk of mild/moderate ED (HR 1.16; P = 0.02) and aspirin use was associated with an increased risk of severe ED (HR 1.16; P = 0.03, respectively). The associations of NSAID use with ED risk were attenuated after controlling for indications for NSAID use.

CONCLUSIONS

The modest associations of NSAID use with ED risk in the present cohort were probably attributable to confounding indications for NSAID use. NSAID use was not associated with ED risk.

Serum 25-hydroxyvitamin D concentrations and risk of prostate cancer: results from the Prostate Cancer Prevention Trial

BACKGROUND

Epidemiologic studies have reported inconsistent associations of vitamin D and prostate cancer risk; however, few have adequately controlled for detection bias related to prostate-specific antigen (PSA) screening, and the results of many studies may be affected by occult prostate cancers among controls.

METHODS

Data for this nested case-control analysis (n = 1,695 cases/1,682 controls) are from the Prostate Cancer Prevention Trial. Baseline serum was analyzed for 25-hydroxyvitamin D [25(OH)D]. The presence or absence of cancer was subsequently determined by prostate biopsy. Polytomous logistic regression models were used to estimate associations of 25(OH)D with risk of total, Gleason 2-6, Gleason 7, and Gleason 8-10 prostate cancer. Results are presented for placebo and finasteride arms separately and combined.

RESULTS

There were no associations of serum 25(OH)D with total prostate cancer risk. For Gleason 2-6 cancers, results were inconsistent across treatment arms with a suggestion of increased risk in the placebo arm only; however, there was no dose-response relationship. For Gleason 8-10 prostate cancers, 25(OH)D concentrations were associated with a linear decrease in risk among combined treatment arms [quartile 4 vs. 1: OR, 0.55; 95% confidence interval (CI), 0.32-0.94; P(trend) = 0.04]. These findings were somewhat stronger among men ≥65 versus 55-64 years at baseline (quartile 4 vs. 1: OR, 0.40; 95% CI, 0.18-0.88 vs. OR, 0.73; 95% CI, 0.35-1.52, respectively; P(interaction) = 0.52).

CONCLUSIONS

Higher serum 25(OH)D may modestly increase risk of Gleason 2-6 disease and more substantially reduce risk of Gleason 8-10 prostate cancer.

IMPACT

Vitamin D may have different effects for different stages of prostate cancers.

Finasteride concentrations and prostate cancer risk: results from the Prostate Cancer Prevention Trial

OBJECTIVE

In the Prostate Cancer Prevention Trial (PCPT), finasteride reduced the risk of prostate cancer by 25%, even though high-grade prostate cancer was more common in the finasteride group. However, it remains to be determined whether finasteride concentrations may affect prostate cancer risk. In this study, we examined the association between serum finasteride concentrations and the risk of prostate cancer in the treatment arm of the PCPT and determined factors involved in modifying drug concentrations.

METHODS

Data for this nested case-control study are from the PCPT. Cases were drawn from men with biopsy-proven prostate cancer and matched controls. Finasteride concentrations were measured using a liquid chromatography-mass spectrometry validated assay. The association of serum finasteride concentrations with prostate cancer risk was determined by logistic regression. We also examine whether polymorphisms in the enzyme target and metabolism genes of finasteride are related to drug concentrations using linear regression.

RESULTS AND CONCLUSIONS

Among men with detectable finasteride concentrations, there was no association between finasteride concentrations and prostate cancer risk, low-grade or high-grade, when finasteride concentration was analyzed as a continuous variable or categorized by cutoff points. Since there was no concentration-dependent effect on prostate cancer, any exposure to finasteride intake may reduce prostate cancer risk. Of the twenty-seven SNPs assessed in the enzyme target and metabolism pathway, five SNPs in two genes, CYP3A4 (rs2242480; rs4646437; rs4986910), and CYP3A5 (rs15524; rs776746) were significantly associated with modifying finasteride concentrations. These results suggest that finasteride exposure may reduce prostate cancer risk and finasteride concentrations are affected by genetic variations in genes responsible for altering its metabolism pathway.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00288106.

Association between Serum Phospholipid Fatty Acids and Intraprostatic Inflammation in the Placebo Arm of the Prostate Cancer Prevention Trial

Inflammation may play an etiologic role in prostate cancer. Several dietary factors influence inflammation; studies have shown that long-chain n-3 polyunsaturated fatty acids are anti-inflammatory, whereas n-6 and trans fatty acids are proinflammatory. We evaluated whether serum phospholipid n-3, n-6, and trans fatty acids were associated with intraprostatic inflammation, separately in 191 prostate cancer cases and 247 controls from the placebo arm of the Prostate Cancer Prevention Trial (PCPT). Men without a prostate cancer diagnosis underwent prostate biopsy at trial end, and benign prostate tissue inflammation was evaluated in approximately three biopsy cores per man; this was expressed as no, some, or all cores with inflammation. In controls, serum eicosapentaenoic acid [OR of all cores with inflammation versus none (95% CI), 0.35 (0.14-0.89)] and docosahexaenoic acid [OR (95% CI), 0.42 (0.17-1.02)] were inversely associated with, whereas linoleic acid [OR (95% CI), 3.85 (1.41-10.55)] was positively associated with intraprostatic inflammation. Serum trans fatty acids were not associated with intraprostatic inflammation. No significant associations were observed in cases; however, we could not rule out a positive association with linoleic acid and an inverse association with arachidonic acid. Thus, in the PCPT, we found that serum n-3 fatty acids were inversely, n-6 fatty acids were positively, and trans fatty acids were not associated with intraprostatic inflammation in controls. Although, in theory, inflammation could mediate associations of serum fatty acids with prostate cancer risk, our findings cannot explain the epidemiologic associations observed with n-3 and n-6 fatty acids.

Associations of Obesity with Prostate Cancer Risk Differ Between U.S. African-American and Non-Hispanic White Men: Results from the Selenium and Vitamin E Cancer Prevention Trial

African-American (AA) men have the highest rates of prostate cancer incidence and mortality in the US. Understanding underlying reasons for this disparity could identify preventive interventions important to AA men. PURPOSE: To determine whether the association of obesity with prostate cancer risk differs between AA and non-Hispanic white (NHW) men and whether obesity modifies the excess risk associated with AA race. METHODS: This is a prospective study among 3398 AA and 22673 NHW men who participated in the Selenium and Vitamin E Cancer Prevention Trial (2001–2011). Using Cox regression, we estimated hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) associated with AA and NHW race and body mass index (BMI) [kg/m2] on total, low- (Gleason score &lt;7), and high-grade (Gleason score ≥7) prostate cancer incidence while adjusting for relevant covariates. RESULTS: There were 270, 148, and 88 cases of total, low-, and high-grade prostate cancers among AA men and a corresponding 1453, 898, and 441 cases in NHW men (median follow-up of 5.6 years). BMI was not associated with risk of total cancer among NHW men, but was positively associated with risk among AA men (BMI &lt; 25 kg/m2 vs. ≥35 kg/m2, HR = 1.49; 95% CI, 0.95–2.34; Ptrend = 0.03). Consequently, the risk associated with AA race increased from 28% (HR = 1.28; 95% CI, 0.91–1.80) among men with BMI &lt; 25 kg/m2 to 103% (HR = 2.03; 95% CI, 1.38–2.98) among AA men with BMI≥35 kg/m2 (Ptrend = 0.03). BMI was inversely associated with low-grade prostate cancer risk among NHW men (BMI &lt; 25 kg/m2 vs. ≥35 kg/m2, HR = 0.80; 95% CI, 0.58–1.09; Ptrend = 0.02), but positively associated with risk among AA men (BMI &lt; 25 kg/m2 vs. ≥35 kg/m2, HR = 1.77; 95% CI, 1.14–2.76; Ptrend = 0.05). BMI was positively associated with risk of high-grade prostate cancer in both NHW (BMI &lt; 25 kg/m2 vs. ≥35 kg/m2, HR = 1.33; 95% CI, 0.90–1.97; Ptrend = 0.01) and AA men (BMI &lt; 25 kg/m2 vs. ≥35 kg/m2, HR = 1.81; 95% CI, 0.79–4.11; Ptrend = 0.02), but associations were not significantly different. CONCLUSION: Obesity is more strongly associated with increased prostate cancer risk among AA than NHW men and reducing obesity among AA men could reduce the racial disparity in cancer incidence. Research is needed to test mechanisms underpinning these associations.

Plasma vitamin D and prostate cancer risk: results from the Selenium and Vitamin E Cancer Prevention Trial

BACKGROUND

In vitro, animal, and ecological studies suggest that inadequate vitamin D intake could increase prostate cancer risk, but results of biomarker-based longitudinal studies are inconsistent.

METHODS

Data for this case (n = 1,731) and cohort (n = 3,203) analysis are from the Selenium and Vitamin E Cancer Prevention Trial. Cox proportional hazard models were used to test whether baseline plasma vitamin D (25-hydroxy) concentration, adjusted for season of blood collection, was associated with the risk of total and Gleason score 2-6, 7-10, and 8-10 prostate cancer.

RESULTS

There were U-shaped associations of vitamin D with total cancer risk: compared with the first quintile, HRs were 0.83 [95% confidence interval (CI), 0.66-1.03; P = 0.092], 0.74 (95% CI, 0.59-0.92; P = 0.008), 0.86 (95% CI, 0.69-1.07; P = 0.181), and 0.98 (95% CI, 0.78-1.21; P = 0.823), for the second through fifth quintiles, respectively. For Gleason 7-10 cancer, corresponding HRs were 0.63 (95% CI, 0.45-0.90; P = 0.010), 0.66 (95% CI, 0.47-0.92; P = 0.016), 0.79 (95% CI, 0.56-1.10; P = 0.165), and 0.88 (95% CI, 0.63-1.22; P = 0.436). Among African American men (n = 250 cases), higher vitamin D was associated with reduced risk of Gleason 7-10 cancer only: in the a posteriori contrast of quintiles 1-2 versus 3-5, the HR was 0.55 (95% CI, 0.31-0.97; P = 0.037), with no evidence of dose-response or a U-shaped association.

CONCLUSIONS

Both low and high vitamin D concentrations were associated with increased risk of prostate cancer, and more strongly for high-grade disease.

IMPACT

The optimal range of circulating vitamin D for prostate cancer prevention may be narrow. Supplementation of men with adequate levels may be harmful. Cancer Epidemiol Biomarkers Prev; 23(8); 1494-504. ©2014 AACR.

Should modest elevations in prostate-specific antigen, International Prostate Symptom Score, or their rates of increase over time be used as surrogate measures of incident benign prostatic hyperplasia?

Although surrogate measures of benign prostatic hyperplasia (BPH) are often used in epidemiologic studies, their performance characteristics are unknown. Using data from the Prostate Cancer Prevention Trial (n = 5,986), we evaluated prostate-specific antigen (PSA), International Prostate Symptom Score (IPSS), and their rates of change as predictors of incident BPH. BPH (n = 842 cases) was defined as medical or surgical treatment or at least 2 IPSS of 15 or higher. Proportional hazards models were used to measure the associations of baseline PSA, IPSS, and their velocities over 2 years with BPH risk, and time-dependent receiver-operating characteristic curves were used to measure their discriminatory performance. Unit increases in PSA, IPSS, and IPSS velocity were associated with 34%, 35%, and 29% (all P < 0.001) increases in BPH risk, respectively. The areas under the receiver-operating characteristic curves were significantly greater than 0.5 for PSA (0.58, 95% confidence interval (CI): 0.56, 0.60), IPSS (0.77, 95% CI: 0.75, 0.78), and IPSS velocity (0.63, 95% CI: 0.61, 0.65); however there were no cut points at which sensitivity and specificity were both above 75%. We concluded that moderate elevations in PSA, IPSS, or their rates of change should not be used as surrogate measures of incident BPH.

Finasteride reduces the risk of incident clinical benign prostatic hyperplasia

BACKGROUND

Despite the high prevalence of clinical benign prostatic hyperplasia (BPH) among older men, there remains a notable absence of studies focused on BPH prevention.

OBJECTIVE

To determine if finasteride prevents incident clinical BPH in healthy older men.

DESIGN, SETTING, AND PARTICIPANTS

Data for this study are from the Prostate Cancer Prevention Trial. After excluding those with a history of BPH diagnosis or treatment, or an International Prostate Symptom Score (IPSS) ≥ 8 at study entry, 9253 men were available for analysis.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome was incident clinical BPH, defined as the initiation of medical treatment, surgery, or sustained, clinically significant urinary symptoms (IPSS >14). Finasteride efficacy was estimated using Cox proportional regression models to generate hazards ratios (HRs).

RESULTS AND LIMITATIONS

Mean length of follow-up was 5.3 yr. The rate of clinical BPH was 19 per 1000 person-years in the placebo arm and 11 per 1000 person-years in the finasteride arm (p<0.001). In a covariate-adjusted model, finasteride reduced the risk of incident clinical BPH by 40% (HR: 0.60; 95% confidence interval, 0.51-0.69; p<0.001). The effect of finasteride on incident clinical BPH was attenuated in men with a body mass index ≥ 30 kg/m(2) (p(interaction) = 0.04) but otherwise did not differ significantly by physical activity, age, race, current diabetes, or current smoking. The post hoc nature of the analysis is a potential study limitation.

CONCLUSIONS

Finasteride substantially reduces the risk of incident clinical BPH in healthy older men. These results should be considered in formulating recommendations for the use of finasteride to prevent prostate diseases in asymptomatic older men.

Indications for and use of nonsteroidal antiinflammatory drugs and the risk of incident, symptomatic benign prostatic hyperplasia: results from the prostate cancer prevention trial

The authors conducted a cohort study of nonsteroidal antiinflammatory drug (NSAID) use and risk of symptomatic benign prostatic hyperplasia (BPH), using data from 4,735 men without BPH at baseline in the placebo arm of the Prostate Cancer Prevention Trial (1993-2003). Incident BPH (n = 471) was defined as medical or surgical treatment or at least 2 International Prostate Symptom Score (I-PSS) values greater than or equal to 15. Proportional hazards models using time-dependent exposure for NSAID use were employed to estimate covariate-adjusted associations of NSAID-related medical conditions and NSAID use with BPH risk. Arthritis, other inflammation-related musculoskeletal conditions, and headaches were associated with increased BPH risk (hazard ratio (HR) = 1.77 (95% confidence interval (CI): 1.37, 2.29), HR = 1.57 (95% CI: 1.14, 2.17), and HR = 1.40 (95% CI: 1.09, 1.80), respectively). Use of any NSAID, use of aspirin, and use of nonaspirin NSAIDs were associated with significant increases in BPH risk (HR = 1.21 (95% CI: 1.01, 1.46), HR = 1.20 (95% CI: 1.00, 1.45), and HR = 1.34 (95% CI: 1.07, 1.69), respectively). Control for indications for NSAID use, including baseline I-PSS, attenuated the associations slightly, but all became nonsignificant. Among men with no indications for NSAID use, the hazard ratio for any NSAID use was 1.06 (95% CI: 0.82, 1.38). The modest associations of NSAID use with BPH risk in this cohort were probably due to confounding by indication, and NSAID use was not associated with BPH risk.

Association of symptomatic benign prostatic hyperplasia and prostate cancer: results from the prostate cancer prevention trial

This study examined the association between symptomatic benign prostatic hyperplasia (BPH) and prostate cancer risk in 5,068 placebo-arm participants enrolled in the Prostate Cancer Prevention Trial (1993-2003). These data include 1,225 men whose cancer was detected during the 7-year trial--556 detected for cause (following abnormal prostate-specific antigen or digital rectal examination) and 669 detected not for cause (without indication), as well as 3,843 men who had biopsy-proven absence of prostate cancer at the trial end. Symptomatic BPH was assessed hierarchically as self-report of surgical or medical treatment, moderately severe symptoms (International Prostate Symptom Score >14), or physician diagnosis, and analyses were completed by BPH status at baseline (prevalent) or BPH prior to cancer diagnosis or study end (prevalent plus incident). Controlled for age, race, and body mass index, neither prevalent (risk ratio = 1.03, 95% confidence interval: 0.92, 1.14) nor prevalent plus incident (risk ratio = 0.96, 95% confidence interval: 0.87, 1.06) symptomatic BPH was associated with prostate cancer risk. This lack of association was consistent across subgroups defined by type of BPH-defining event (treatment, symptoms, or physician diagnosis), prompt for prostate cancer diagnosis, and prostate cancer grade. This study provides the strongest evidence to date that BPH does not increase the risk of prostate cancer.

Brief telephone intervention increases soy intake in peri- and postmenopausal US women: the Herbal Alternatives Trial (HALT)

OBJECTIVE

Effective dietary intervention strategies that can be widely disseminated and have the potential for sustainable dietary modifications are needed. The purpose of this study was to describe and evaluate the effectiveness of a telephone-based soy intervention.

DESIGN

A randomized controlled trial comparing self-reported intake and serum measures of soy during a 1-year dietary soy (Soy) to fruit and vegetable (Placebo) intervention conducted in two of five arms from the Herbal Alternatives Trial between May 2001 and September 2004.

SUBJECTS/SETTING

One hundred sixty-three peri- and postmenopausal women (mean age=52 years) consuming self-selected diets in the Pacific Northwest, United States.

INTERVENTION

Five telephone contacts with a registered dietitian during a 12-month intervention with the goal to increase soy food consumption to two servings daily.

MAIN OUTCOME MEASURES

Change from baseline in self-reported soy servings and serum isoflavone (daidzein and genistein) concentrations were estimated using analysis of variance and generalized estimating equations. Proportions of participants achieving the intervention goal were compared using chi(2) tests.

RESULTS

Ninety-four percent (n=74) of participants in the Soy arm and 89% (n=75) in the Placebo arm completed the trial, and slightly more than one third (n=27) received five phone contacts. Mean (+/-standard deviation) intakes of soy were similar for the Soy and Placebo arms at baseline (0.6+/-1.0 vs 0.4+/-0.8 servings/day; P>0.05). At 12-month follow-up visit, mean+/-standard deviation servings of soy per day were 1.6+/-1.4 for the Soy intervention compared to 0.5+/-0.9 within the Placebo arm (P<0.001). There were concomitant increases in serum isoflavones at 3 and 6 months from baseline in the Soy arm only, with approximately twofold increases in both daidzein (mean=66.4 nmol/L, 95% confidence interval [CI]: 39.0 to 93.9 [mean 16.9 ng/mL, 95% CI: 9.9 to 23.8]) and genistein (mean=100.4 nmol/L, 95% CI: 60.9 to 139.9 [mean 27.1 ng/mL, 95% CI: 16.5 to 37.8]) concentrations. Mean weight changed by <1 kg during the 12-month period in each group and physical activity remained stable, suggesting that participants incorporated soy foods into their diet by substituting for non soy foods rather than adding them to their diet.

CONCLUSIONS

A brief telephone-based intervention with a focused message delivered by a registered dietitian is a feasible approach for encouraging targeted dietary changes, such as an increase in soy intake among peri- and postmenopausal women.

Androgen receptor CAG repeat length is not associated with the risk of incident symptomatic benign prostatic hyperplasia: results from the Prostate Cancer Prevention Trial

BACKGROUND

To examine whether androgen receptor (AR) CAG repeat length was associated with the risk of incident benign prostatic hyperplasia (BPH).

METHODS

A nested case-control study of 416 BPH cases and 527 controls drawn from Prostate Cancer Prevention Trial placebo-arm participants who were free of BPH at baseline. BPH was assessed over 7 years and was defined as receipt of medical or surgical treatment, two scores > 14 on the International Prostate Symptom Score (IPSS), or two increases in IPSS > or = 5 with at least one score > or = 12.

RESULTS

Compared to men with AR repeat length < or = 19, the covariate-adjusted odds ratios [95% CI] were 1.07 [0.73, 1.57] and 0.90 [0.55, 1.45]) for repeat length 20-24 and > or =25, respectively. There was a weak association of AR repeat length with baseline serum testosterone (T) (Spearman r = 0.09, p < 0.02); however, control for or stratification by T did not change study results. Further, results did not differ when stratified by body mass index or baseline concentration of 3alpha-diol glucoronide, and were similar for all BPH definitions.

CONCLUSIONS

There were no associations of AR CAG repeat length and BPH risk. Knowledge of AR CAG repeat length provides no clinical useful information for the prevention of symptomatic BPH.

Biomarkers of systemic inflammation and risk of incident, symptomatic benign prostatic hyperplasia: results from the prostate cancer prevention trial

The authors conducted a nested case-control study of serum inflammatory markers and risk of symptomatic benign prostatic hyperplasia (BPH), using data from the placebo arm of the Prostate Cancer Prevention Trial (1993-2003). Incident BPH (n = 676) was defined as treatment, report of 2 International Prostate Symptom Score (IPSS) values >14, or 2 increases of > or = 5 from baseline values with at least one value > or = 12. Controls (n = 683) were men who reported no BPH treatment or IPSS values >7 over the 7-year trial. Baseline serum was analyzed for C-reactive protein, tumor necrosis factor alpha (monomer), soluble tumor necrosis factor receptors I and II (sTNF-RI and sTNF-RII), interleukin 6, and interferon gamma. Controlled for age and race, a high C-reactive protein concentration was associated with increased BPH risk (for quartile 4 vs. quartile 1, odds ratio (OR) = 1.40, 95% confidence interval (CI): 1.04, 1.88); this was attenuated after control for body mass index (OR = 1.30, 95% CI: 0.95, 1.75). Low sTNF-RII and high interleukin 6 concentrations were associated with increased BPH risk (for quartile 4 vs. quartile 1, sTNF-RII: OR = 0.61, 95% CI: 0.46, 0.82; interleukin 6: OR = 1.79, 95% CI: 1.32, 2.42); these associations were only in men aged <65 years. Results suggest that systemic inflammation or lower levels of soluble receptors that bind inflammatory cytokines increase BPH risk.

Serum adiponectin, C-peptide and leptin and risk of symptomatic benign prostatic hyperplasia: results from the Prostate Cancer Prevention Trial

BACKGROUND

Recent epidemiologic studies have identified obesity as a risk factor for benign prostatic hyperplasia (BPH). We examined whether adiponectin, leptin, and C-peptide were associated with incident, symptomatic BPH and whether these factors mediate the relationship between obesity and BPH risk.

METHODS

Data are from Prostate Cancer Prevention Trial placebo arm participants who were free of BPH at baseline. Incident BPH (n = 698) was defined as treatment, two International Prostate Symptom Score (IPSS) values > 14, or an increase of >or=5 in IPSS from baseline documented on at least two occasions plus at least one score >or=12. Controls (n = 709) were selected from men reporting no BPH treatment or IPSS > 7 during the 7-year trial. Baseline serum was analyzed for adiponectin, C-peptide, and leptin concentrations.

RESULTS

Neither C-peptide nor leptin was associated with BPH risk. The odds ratio [95% CI] contrasting highest to lowest quartiles of adiponectin was 0.65[0.47, 0.87] P(trend) = 0.004. Findings differed between levels of physical activity: there was a strong inverse association between adiponectin and BPH among moderately/very active men OR = 0.43 [0.29, 0.63], and no association among sedentary/minimally active men OR = 0.92 [0.65, 1.30] P(interaction) = 0.005. Adiponectin concentrations explained only a moderate amount of the relationship between obesity and BPH risk.

CONCLUSIONS

High adiponectin concentrations were associated with reduced risk of incident, symptomatic BPH. This association was limited to moderately/very active men; suggesting the relationship between obesity and BPH involves a complex interaction between factors affecting glucose uptake and insulin sensitivity. However, adiponectin is likely not the only mechanism through which obesity affects BPH risk.

Alcohol consumption, finasteride, and prostate cancer risk: results from the Prostate Cancer Prevention Trial

BACKGROUND

Current research is inconclusive regarding the relation between alcohol consumption and prostate cancer risk. In this study, the authors examined the associations of total alcohol, type of alcoholic beverage, and drinking pattern with the risk of total, low-grade, and high-grade prostate cancer.

METHODS

Data for this study came from the 2129 participants in the Prostate Cancer Prevention Trial (PCPT) who had cancer detected during the 7-year trial and 8791 men who were determined by biopsy to be free of cancer at the trial end. Poisson regression was used to calculate relative risks (RRs) and 95% confidence intervals (95% CIs) for associations of alcohol intake with prostate cancer risk.

RESULTS

Associations of drinking with high-grade disease did not differ by treatment arm. In combined arms, heavy alcohol consumption (> or =50 g of alcohol daily) and regular heavy drinking (> or =4 drinks daily on > or =5 days per week) were associated with increased risks of high-grade prostate cancer (RR, 2.01 [95% CI, 1.33-3.05] and 2.17 [95% CI, 1.42-3.30], respectively); less heavy drinking was not associated with risk. Associations of drinking with low-grade cancer differed by treatment arm. In the placebo arm, there was no association of drinking with risk of low-grade cancer. In the finasteride arm, drinking > or =50 g of alcohol daily was associated with an increased risk of low-grade disease (RR, 1.89; 95% CI, 1.39-2.56); this finding was because of a 43% reduction in the risk of low-grade cancer attributable to finasteride treatment in men who drank <50 g of alcohol daily and the lack of an effect of finasteride in men who drank > or =50 g of alcohol daily (P(interaction) = .03).

CONCLUSIONS

Heavy, daily drinking increased the risk of high-grade prostate cancer. Heavy drinking made finasteride ineffective for reducing prostate cancer risk.