Experimental studies suggest that marine fatty acids have an antitumor effect on prostate tumor cells. The aim of this study was to investigate whether high consumption of fish and marine fatty acids reduces the risk of prostate cancer in humans. We followed 47,882 men participating in the Health Professionals Follow-up Study. Dietary intake was assessed in 1986, 1990, and 1994, using a validated food frequency questionnaire. During 12 years of follow-up, 2,482 cases of prostate cancer were diagnosed, of which 617 were diagnosed as advanced prostate cancer including 278 metastatic prostate cancers. Eating fish more than three times per week was associated with a reduced risk of prostate cancer, and the strongest association was for metastatic cancer (multivariate relative risk, 0.56; 95% confidence interval, 0.37-0.86, compared with infrequent consumption, i.e., less than twice per month). Intake of marine fatty acids from food showed a similar but weaker association. Each additional daily intake of 0.5 g of marine fatty acid from food was associated with a 24% decreased risk of metastatic cancer. We found that men with high consumption of fish had a lower risk of prostate cancer, especially for metastatic cancer. Marine fatty acids may account for part of the effect, but other factors in fish may also play a role.
Background: Few studies have investigated the association between post-diagnosis physical activity and mortality among men diagnosed with prostate cancer. The aim of this study was to investigate the effect of physical activity after a prostate cancer diagnosis on both overall and prostate cancer-specific mortality in a large cohort. Methods: Data from 4,623 men diagnosed with localized prostate cancer 1997-2002 and followed-up until 2012 were analyzed. HRs with 95% confidence intervals (CI) were estimated using Cox proportional hazards models to examine the association between post-diagnosis recreational MET-h/d, time spent walking/bicycling, performing household work or exercising, and time to overall and prostate cancer-specific death. All models were adjusted for potential confounders. Results: During the follow-up, 561 deaths of any cause and 194 deaths from prostate cancer occurred. Statistically significantly lower overall mortality rates were found among men engaged in 5 recreationalMET-h/d (HR, 0.63; 95% CI, 0.52-0.77), walking/ bicycling 20 min/d (HR, 0.70; 95% CI, 0.57-0.86), performing householdwork > 1 h/d (HR, 0.71; 95% CI, 0.59-0.86), or exercising > 1 h/wk (HR, 0.74; 95% CI, 0.61-0.90), compared with less active men within each activity type. For prostate cancer-specific mortality, statistically significantly lower mortality rates were seen among men walking/bicycling >= 20 min/d (HR, 0.61; 95% CI, 0.43-0.87) or exercising 1 h/wk (HR, 0.68; 95% CI, 0.48-0.94). Conclusions: Higher levels of physical activity were associated with reduced rates of overall and prostate cancer-specific mortality. Impact: Our study further strengthens previous results indicating beneficial effects of physical activity on survival among men with prostate cancer. Cancer Epidemiol Biomarkers Prev; 24(1); 57-64. (C) 2014 AACR.
Background: Somatostatin (SST) and its receptors (SSTR1-5) may have a role in prostate cancer by influencing the IGFI hormone axis or through direct effects on prostate epithelia. We have investigated if genetic variation in the SST and SSTR1-5 genes influences prostate cancer risk and/or circulating IGFI and IGFBP3 hormone levels. Materials and Methods: We analyzed 28 haplotype tagging single nucleotide polymorphisms in the SST and SSTR1-5 genes in a case-control/genetic association study to investigate the association between genetic variation and prostate cancer risk. The study included 2863 cases and 1737 controls from the Cancer Prostate in Sweden (CAPS) study. To investigate the genetic influence on circulating hormone levels, plasma concentrations of IGFI and IGFBP3 were analyzed in 874 controls of the CAPS study and 550 male subjects from the Northern Sweden Health and Disease Cohort (NSHDC). Results: No clear association between prostate cancer risk and genetic variation of the SST and SSTR1-5 genes was identified. The SSTR5 missense single nucleotide polymorphism rs4988483 was associated with circulating IGFI (P = 0.002) and IGFBP3 (P = 0.0003) hormone levels in CAPS controls, with a per allele decrease of similar to 11%. This decrease was replicated in NSHDC for circulating IGFBP3 (P = 0.01) but not for IGFI (P = 0.09). Combining CAPS and NSHDC subjects indicated evidence of association between rs4988483 and both IGFBP3 (P = 2 x 10(-5)) and IGFI (P = 0.0004) hormone levels. Conclusions: Our results suggest that genetic variation in the SSTR5 gene and, particularly, the rs4988483 single nucleotide polymorphism influence circulating IGFI and IGFBP3 hormone levels with no measurable effect on prostate cancer risk. (Cancer Epidemiol Biomarkers Prev 2009;18(5):164.4-50)
The growth hormone receptor (GHR) is potentially involved in prostate cancer through its role in stimulating insulin-like growth factor I production and its cellular effects on prostate epithelium. We have used a haplotype-based tagging approach within CAncer Prostate Sweden, a large retrospective case-control study of 2,863 cases and 1,737 controls to investigate if genetic variation in the GHR gene influences prostate cancer risk. One haplotype in the 3' region of the GHR gene was found associated with prostate cancer risk in elderly men (> 65 years old at the time of diagnosis), with heterozygote haplotype carriers having an odds ratio of 1.65 (95% confidence interval, 1.21-2.16; P = 0.0009, P-corrected = 0.03). GHR function has been implicated in the determination of body mass index. Interestingly, the same haplotype associated with risk in the 3' end of the GHR gene was also associated with a decrease in body mass index in controls (P = 0.003, P-corrected = 0.05), possibly indicating some functionality with this haplotype. These results suggest that whereas genetic variation in the GHR gene does not seem to play a major role in prostate cancer etiology, one haplotype in the 3' region may be potentially relevant to cases with later onset of prostate cancer.
Chronic or recurrent inflammation has been suggested as a causal factor in several human malignancies, including prostate cancer. Genetic predisposition is also a strong risk factor in the development of prostate cancer. In particular, Toll-like receptors (TLR), especially the TLR6-1-10 gene cluster, are involved in prostate cancer development. Interleukin-1 receptor-associated kinases (IRAK) 1 and 4 are critical components in the TLR signaling pathway. In this large case-control study, we tested two hypotheses: (a) sequence variants in IRAK1 and IRAK4 are associated with prostate cancer risk and (b) sequence variants in IRAK1/4 and TLR1-6-10 interacts and confers a stronger risk to prostate cancer. We analyzed 11 single nucleotide polymorphisms (four in IRAK1 and seven in IRAK4) among 1,383 newly diagnosed prostate cancer patients and 780 population controls in Sweden. Although the single-nucleotide polymorphisms in IRAK1 and IRAK4 alone were not significantly associated with prostate cancer risk, one single-nucleotide polymorphism in IRAK4, when combined with the high-risk genotype at TLR6-1-10, conferred a significant excess risk of prostate cancer. In particular, men with the risk genotype at TLR6-1-10 and IRAK4-7987 CG/CC had an odds ratio of 9.68 (P = 0.03) when compared with men who had wildtype genotypes. Our findings suggest synergistic effects between sequence variants in IRAK4 and the TLR 6-1-10 gene cluster. Although this study was based on a priori hypothesis and was designed to address many common issues facing this type of study, our results need confirmation in even larger studies.
Prostate carcinoma is the most common cancer in men. Its primary pathogenesis is mostly unknown. Dairy products containing lactose have been suggested to be risk factors for prostate cancer. Digestion of lactose is dependent on lactase activity in the intestinal wall. A single nucleotide polymorphism C to T residing 13,910 bp upstream of the lactase gene has been shown to associate with the developmental down-regulation of lactase activity underlying persistence/nonpersistence trait. To find out whether lactase persistence is related to the risk for prostate cancer, we genotyped 1,229 Finnish and 2,924 Swedish patients and their 473 Finnish and 1,842 Swedish controls using solid-phase minisequencing. To explore if dairy products have an association with prostate cancer, we analyzed the milk consumption in the Swedish study consisting of 1,499 prostate cancer patients and 1,130 controls (Cancer Prostate in Sweden I study) using a questionnaire. Only the consumption of low-fat milk was found to be associated with increased risk of prostate cancer [odds ratio (OR), 1.73; 95% confidence interval (95% CI), 1.162.391. A statistically significantly higher (P < 0.01) lactose intake was observed among subjects with high lactase activity (C/T and T/T genotypes) compared with those with low lactase activity (C/C genotype). Lactase persistence did not associate with increased risk for prostate carcinoma in the Finnish (OR, 1.11; 95% CI, 0.83-1.47, P = 0.488) or in the Swedish populations (OR, 1.16; 95% CI, 0.91-1.46; P = 0.23). In conclusion, lactase persistence/nonpersistence contains no risk for prostate cancer. Analysis of different milk products showed some evidence for low-fat milk as a potential risk factor for prostate cancer.
The aim of this study was to evaluate loss of information from a reduced food frequency questionnaire as compared with an extensive reference method developed to assess the intake of heterocyclic amines (HCAs), Food frequency data were linked to concentrations of HCAs in cooked foods to estimate the individual daily exposure to a combination of five HCAs. The number of food items in the questionnaire was reduced and selected in three ways: (a) according to the contribution to the estimated total intake; (b) the between-person variance; or (c) dishes included in other studies. The effect on sensitivity, specificity, concordance, the correlation coefficient, kappa, and simulated relative risks was determined using information from a population-based study conducted in Stockholm. Only a limited amount of misclassification was introduced when the number of dishes was reduced from 39 to 15 or 20, and no major difference was seen when dishes were selected according to the total intake or the between-person variance. Our data indicate that for a specific exposure, such as HCAs, the loss of accuracy in an analytical epidemiological study is small and may not be relevant when the number of dishes in a food frequency questionnaire is decreased, if the initially chosen dishes are carefully selected and cover a reasonable part of the total intake or between-person variance.