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Epidemiologic studies examining the association between specific fatty acids and colorectal cancer (CRC) risk are inconclusive. We investigated the association between dietary estimates and plasma levels of individual and total saturated (SFA), monounsaturated (MUFA), industrial-processed trans (iTFA), and ruminant-sourced trans (rTFA) fatty acids, and CRC risk in the European Prospective Investigation into Cancer and Nutrition (EPIC). Baseline fatty acid intakes were estimated in 450 112 participants (6162 developed CRC, median follow-up = 15 years). In a nested case-control study, plasma phospholipid fatty acids were determined by gas chromatography in 433 colon cancer cases and 433 matched controls. Multivariable-adjusted hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs) were computed using Cox and conditional logistic regression, respectively. Dietary total SFA (highest vs lowest quintile, HRQ5vsQ1  = 0.80; 95%CI:0.69-0.92), myristic acid (HRQ5vsQ1  = 0.83, 95%CI:0.74-0.93) and palmitic acid (HRQ5vsQ1  = 0.81, 95%CI:0.70-0.93) were inversely associated with CRC risk. Plasma myristic acid was also inversely associated with colon cancer risk (highest vs lowest quartile, ORQ4vsQ1  = 0.51; 95%CI:0.32-0.83), whereas a borderline positive association was found for plasma stearic acid (ORQ4vsQ1  = 1.63; 95%CI:1.00-2.64). Dietary total MUFA was inversely associated with colon cancer (per 1-SD increment, HR1-SD  = 0.92, 95%CI: 0.85-0.98), but not rectal cancer (HR1-SD  = 1.04, 95%CI:0.95-1.15, Pheterogeneity  = 0.027). Dietary iTFA, and particularly elaidic acid, was positively associated with rectal cancer (HR1-SD  = 1.07, 95%CI:1.02-1.13). Our results suggest that total and individual saturated fatty acids and fatty acids of industrial origin may be relevant to the aetiology of CRC. Both dietary and plasma myristic acid levels were inversely associated with colon cancer risk, which warrants further investigation.

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PURPOSE: The evidence from the literature regarding the association of dietary factors and risk of prostate cancer is inconclusive. METHODS: A nutrient-wide association study was conducted to systematically and comprehensively evaluate the associations between 92 foods or nutrients and risk of prostate cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC). Cox proportional hazard regression models adjusted for total energy intake, smoking status, body mass index, physical activity, diabetes and education were used to estimate hazard ratios and 95% confidence intervals for standardized dietary intakes. As in genome-wide association studies, correction for multiple comparisons was applied using the false discovery rate (FDR < 5%) method and suggested results were replicated in an independent cohort, the Netherlands Cohort Study (NLCS). RESULTS: A total of 5916 and 3842 incident cases of prostate cancer were diagnosed during a mean follow-up of 14 and 20 years in EPIC and NLCS, respectively. None of the dietary factors was associated with the risk of total prostate cancer in EPIC (minimum FDR-corrected P, 0.37). Null associations were also observed by disease stage, grade and fatality, except for positive associations observed for intake of dry cakes/biscuits with low-grade and butter with aggressive prostate cancer, respectively, out of which the intake of dry cakes/biscuits was replicated in the NLCS. CONCLUSIONS: Our findings provide little support for an association for the majority of the 92 examined dietary factors and risk of prostate cancer. The association of dry cakes/biscuits with low-grade prostate cancer warrants further replication given the scarcity in the literature.

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BACKGROUND: Much of the current literature on diet-colorectal cancer (CRC) associations focused on studies of single foods/nutrients, whereas less is known about nutrient patterns. We investigated the association between major nutrient patterns and CRC risk in participants of the European Prospective Investigation into Cancer and Nutrition (EPIC) study. METHODS: Among 477 312 participants, intakes of 23 nutrients were estimated from validated dietary questionnaires. Using results from a previous principal component (PC) analysis, four major nutrient patterns were identified. Hazard ratios (HRs) and 95% confidence intervals (CIs) were computed for the association of each of the four patterns and CRC incidence using multivariate Cox proportional hazards models with adjustment for established CRC risk factors. RESULTS: During an average of 11 years of follow-up, 4517 incident cases of CRC were documented. A nutrient pattern characterised by high intakes of vitamins and minerals was inversely associated with CRC (HR per 1 s.d.=0.94, 95% CI: 0.92-0.98) as was a pattern characterised by total protein, riboflavin, phosphorus and calcium (HR (1 s.d.)=0.96, 95% CI: 0.93-0.99). The remaining two patterns were not significantly associated with CRC risk. CONCLUSIONS: Analysing nutrient patterns may improve our understanding of how groups of nutrients relate to CRC.

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BACKGROUND: Prospective cohort studies recruit relatively healthy population samples, resulting in lower morbidity and mortality rates than in the source population. This is known as the healthy volunteer effect. The aim of this study was to define the magnitude and the development over time of the healthy volunteer effect in the EPIC-NL cohort. METHODS: We studied mortality rates in the EPIC-NL cohort, which comprises 37 551 men and women aged 20-70 years at recruitment in 1993-97. The date and cause of death of deceased participants until 2010 were obtained through linkage with the municipal registry and Statistics Netherlands. Standardized mortality ratios (SMRs) were computed by dividing the observed number of deaths by the number of deaths expected from the general Dutch population. Additionally, standardized incidence ratios were calculated to compare cancer incidence. RESULTS: After an average follow-up of 14.9 years, 3029 deaths were documented. Overall mortality in men [SMR 73.5%, 95% confidence interval (CI): 68.1-79.3] and women (SMR 65.9%, 95% CI: 63.2-68.6) was lower compared with the general population for the whole follow-up period. The SMRs clearly increased over the follow-up period. Among women, the SMR was lower for death due to cardiovascular diseases than death due to cancer. Cancer incidence was also lower in EPIC-NL than in the general population (SMR 78.3 and 82.7% for men and women, respectively). CONCLUSION: The results show a healthy volunteer effect in the EPIC-NL cohort, which tapers off with longer follow-up. Therefore, in the first years of follow-up, power might not be sufficient to detect small associations.

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Several prospective studies have shown a moderate positive association between increasing circulating insulin-like growth factor-I (IGF-I) levels and colorectal cancer risk. However, the associations were often statistically nonsignificant, and the relationship of cancer risk with IGF-I's major binding protein, IGFBP-3, showed major discrepancies between studies. We investigated the association of colorectal cancer risk with serum IGF-I, total and intact IGFBP-3, in a case-control study nested within the EPIC cohort (1,121 cases of colorectal cancer and 1,121 matched controls). Conditional logistic regression was used to adjust for possible confounders. Our present study results were combined in a meta-analysis with those from 9 previous prospective studies to examine the overall evidence for a relationship of prediagnostic serum IGF-I with colorectal cancer risk. In the EPIC study, serum concentrations of IGF-I and IGFBP-3 showed no associations with risk of colorectal cancer overall. Only in subgroup analyses did our study show moderate positive associations of IGF-I levels with risk, either among younger participants only (and only for colon cancer) or among participants whose milk intakes were in the lowest tertile of the population distribution (RR for an increase of 100 ng/ml = 1.43 [95% CI = 1.13-1.93]). Nevertheless, in the meta-analysis a modest positive association remained between serum IGF-I and colorectal cancer risk overall (RR = 1.07 [1.01-1.14] for 1 standard deviation increase in IGF-I). Overall, data from our present study and previous prospective studies combined indicate a relatively modest association of colorectal cancer risk with serum IGF-I.

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In contrast to some extensively examined food mutagens, for example, aflatoxins, N-nitrosamines and heterocyclic amines, some other food contaminants, in particular polycyclic aromatic hydrocarbons (PAH) and other aromatic compounds, have received less attention. Therefore, exploring the relationships between dietary habits and the levels of biomarkers related to exposure to aromatic compounds is highly relevant. We have investigated in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort the association between dietary items (food groups and nutrients) and aromatic DNA adducts and 4-aminobiphenyl-Hb adducts. Both types of adducts are biomarkers of carcinogen exposure and possibly of cancer risk, and were measured, respectively, in leucocytes and erythrocytes of 1086 (DNA adducts) and 190 (Hb adducts) non-smokers. An inverse, statistically significant, association has been found between DNA adduct levels and dietary fibre intake (P = 0.02), vitamin E (P = 0.04) and alcohol (P = 0.03) but not with other nutrients or food groups. Also, an inverse association between fibre and fruit intake, and BMI and 4-aminobiphenyl-Hb adducts (P = 0.03, 0.04, and 0.03 respectively) was observed. After multivariate regression analysis these inverse correlations remained statistically significant, except for the correlation adducts v. fruit intake. The present study suggests that fibre intake in the usual range can modify the level of DNA or Hb aromatic adducts, but such role seems to be quantitatively modest. Fibres could reduce the formation of DNA adducts in different manners, by diluting potential food mutagens and carcinogens in the gastrointestinal tract, by speeding their transit through the colon and by binding carcinogenic substances.

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Few epidemiologic studies have examined the hypothesis that circulating androgens are involved in the development of ovarian cancer. We investigated the association between prediagnostic serum levels of androgens and sex hormone-binding globulin (SHBG) and ovarian cancer risk in a case-control study nested within the European Prospective Investigation into Cancer and Nutrition cohort. One hundred and ninety-two ovarian cancer cases and 346 matched controls not using exogenous hormones at baseline blood donation were eligible for the study. Serum levels of testosterone, androstenedione, dehydroepiandrosterone sulfate, and SHBG were measured by direct immunoassays. Free testosterone (fT) was calculated according to mass action laws. Multivariate conditional logistic regression was used to estimate odds ratios adjusted for possible confounders. Overall, there was no association between serum concentrations of androgens or SHBG and ovarian cancer risk. In postmenopausal women, fT concentrations were inversely related to risk [highest versus lowest tertile odds ratio 0.45 (0.24-0.86); P(trend) = 0.01]. Among women diagnosed before the age of 55 years, there was a negative association with SHBG and a positive association with fT and ovarian cancer risk, although these associations were not statistically significant. The present study suggests that circulating androgens and SHBG levels are not strongly associated with ovarian cancer risk, although levels of fT may be associated with an increased risk among women diagnosed at relatively young age. The heterogeneity of results on the associations of fT with ovarian cancer risk in postmenopausal women deserves further investigation.

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It has been hypothesized that chronic hyperinsulinemia, a major metabolic consequence of physical inactivity and excess weight, might increase breast cancer risk by direct effects on breast tissue or indirectly by increasing bioavailable levels of testosterone and estradiol. Within the European Prospective Investigation into Cancer and Nutrition (EPIC), we measured serum levels of C-peptide--a marker for pancreatic insulin secretion--in a total of 1,141 incident cases of breast cancer and 2,204 matched control subjects. Additional measurements were made of serum sex hormone binding globulin (SHBG) and sex steroids. Conditional logistic regression models were used to estimate breast cancer risk for different levels of C-peptide. C-peptide was inversely correlated with SHBG and hence directly correlated with free testosterone among both pre and postmenopausal women. C-peptide and free estradiol also correlated positively, but only among postmenopausal women. Elevated serum C-peptide levels were associated with a nonsignificant reduced risk of breast cancer diagnosed up to the age of 50 years [odds ratio (OR)=0.70, (95% confidence interval (CI), 0.39-1.24); ptrend=0.05]. By contrast, higher levels of C-peptide were associated with an increase of breast cancer risk among women above 60 years of age, however only among those women who had provided a blood sample under nonfasting conditions [OR=2.03, (95% CI, 1.20-3.43); ptrend=0.01]. Our results do not support the hypothesis that chronic hyperinsulinemia generally increases breast cancer risk, independently of age. Nevertheless, among older, postmenopausal women, hyperinsulinemia might contribute to increasing breast cancer risk.

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