60 research outputs found
Serum retinol and prostate cancer risk: a nested case-control study in the prostate, lung, colorectal, and ovarian cancer screening trial.
Vitamin A (retinol) plays a key role in the regulation of cell growth and differentiation, and has been studied as a potential chemopreventive agent for prostate cancer. However, findings from epidemiologic studies on the association between circulating retinol concentrations and the risk of prostate cancer are inconsistent. We examined whether serum concentrations of retinol were associated with the risk of prostate cancer in a nested case-control study using 692 prostate cancer cases and 844 matched controls from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. We estimated the risk of prostate cancer using multivariate, conditional logistic regression to calculate odds ratios and 95% confidence intervals for overall prostate cancer and aggressive disease (stage III or IV or Gleason >7; n = 269). Serum retinol concentrations were not associated with overall prostate cancer risk; however, the highest versus lowest concentrations of serum retinol were associated with a 42% reduction in aggressive prostate cancer risk (P(trend) = 0.02), with the strongest inverse association for high-grade disease (Gleason sum >7; odds ratio, 0.52; 95% confidence interval, 0.32-0.84; P(trend) = 0.01). Our results suggest that higher circulating concentrations of retinol are associated with a decreased risk of aggressive prostate cancer. Further research is needed to better understand the significance of elevations in serum retinol concentrations and the possible biological mechanisms through which retinol affects prostate cancer. (Cancer Epidemiol Biomarkers Prev 2009;18(4):1227-31)
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. Aftermutual 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.</p
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
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
Insulinâlike growth factors (IGFs) and insulinâlike 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 crossâsectional associations of these exposures with circulating concentrations of IGFs (IGFâI and IGFâII) and IGFBPs (IGFBPâ1, IGFBPâ2 and IGFBPâ3). 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 22â89âyears 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 IGFBPâ1 and IGFBPâ2 and lower concentrations of IGFâI, IGFâII and IGFBPâ3. Higher body mass index was associated with lower concentrations of IGFBPâ1 and IGFBPâ2. Taller height was associated with higher concentrations of IGFâI and IGFBPâ3 and lower concentrations of IGFBPâ1. Smokers had higher concentrations of IGFBPâ1 and IGFBPâ2 and lower concentrations of IGFBPâ3 than nonsmokers. Higher alcohol consumption was associated with higher concentrations of IGFâII and lower concentrations of IGFâI and IGFBPâ2. African Americans had lower concentrations of IGFâII, IGFBPâ1, IGFBPâ2 and IGFBPâ3 and Hispanics had lower IGFâI, IGFâII and IGFBPâ3 than nonâHispanic 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
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
A Novel Mobile Structured Light System in Food 3D Reconstruction and Volume Estimation
Over the past ten years, diabetes has rapidly become more prevalent in all age demographics and especially in children. Improved dietary assessment techniques are necessary for epidemiological studies that investigate the relationship between diet and disease. Current nutritional research is hindered by the low accuracy of traditional dietary intake estimation methods used for portion size assessment. This paper presents the development and validation of a novel instrumentation system for measuring accurate dietary intake for diabetic patients. This instrument uses a mobile Structured Light System (SLS), which measures the food volume and portion size of a patient’s diet in daily living conditions. The SLS allows for the accurate determination of the volume and portion size of a scanned food item. Once the volume of a food item is calculated, the nutritional content of the item can be estimated using existing nutritional databases. The system design includes a volume estimation algorithm and a hardware add-on that consists of a laser module and a diffraction lens. The experimental results demonstrate an improvement of around 40% in the accuracy of the volume or portion size measurement when compared to manual calculation. The limitations and shortcomings of the system are discussed in this manuscript
Serum Retinol and Carotenoid Concentrations and Prostate Cancer Risk: Results from the Prostate Cancer Prevention Trial
BackgroundFindings from epidemiologic studies examining associations of serum retinol and carotenoids with prostate cancer risk have been inconsistent. This case-control study nested in the Prostate Cancer Prevention Trial evaluated associations of serum retinol and carotenoids with total, low-, and high-grade prostate cancer risk in a highly screened study population.MethodsWe used logistic regression adjusting for age, family history of prostate cancer, race, body mass index, and serum cholesterol to estimate ORs and 95% confidence intervals (CI) of prostate cancer by quartiles of serum retinol and carotenoids, separately in the placebo (975 cases/1,009 frequency-matched controls) and finasteride (708 cases/743 frequency-matched controls) arms of the trial.ResultsSerum retinol concentrations were associated with increased risk of total prostate cancer [OR (95% CI) comparing the highest quartile of serum retinol with the lowest: 1.30 (1.00-1.68)] and high-grade prostate cancer [OR (95% CI), 1.74 (1.14-2.68)] in the placebo arm of the trial only. Also in the placebo arm, there was a moderate positive association of α-carotene with risk of total prostate cancer [OR (95% CI), 1.32 (1.01-1.73)]. None of the other carotenoids was associated with prostate cancer risk in the placebo arm. No associations were observed for retinol and carotenoids in the finasteride arm.ConclusionIn the placebo arm of this prospective study, high serum retinol and α-carotene concentrations were associated with increased risk of total and high-grade prostate cancers.ImpactMen with higher levels of serum retinol and α-carotene may be at increased risk for prostate cancer
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, 3 alpha-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
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