Anne Tjønneland

Fish consumption and breast cancer risk. The European Prospective Investigation into Cancer and Nutrition (EPIC)

There is current interest in fish consumption and marine omega‐3 (n‐3) fatty acids and breast cancer risk. Some in vitro and animal studies have suggested an inhibitory effect of marine n‐3 fatty acids on breast cancer growth, but the results from epidemiological studies that have examined the association between fish consumption and breast cancer risk in humans are inconsistent. We examined fish consumption and breast cancer risk in 310,671 women aged between 25 and 70 yr at recruitment into the European Prospective Investigation Into Cancer and Nutrition (EPIC). The participants completed a dietary questionnaire between 1992–98 and were followed up for incidence of breast cancer for a median of 6.4 yr. Hazard ratio for breast cancer by intake of total and lean and fatty fish were estimated, stratified by study centre and adjusted for established breast cancer risk factors. During follow‐up, 4,776 invasive incident breast cancers were reported. No significant associations between intake of total fish and breast cancer risk were observed, hazard ratio (HR) 1.01 (95% confidence interval [CI] 0.99–1.02; p = 0.28 per 10 g fish/day). When examining lean and fatty fish separately, we found a positive significant association only in the highest quintile for fatty fish (HR 1.13, 95% CI 1.01–1.26), but test for trend was not significant (p = 0.10). No associations with breast cancer risk were observed when the study participants were subdivided by menopausal status. Although the period of follow‐up is relatively short, the results provide no evidence for an association between fish intake and breast cancer risk.

Hormonal, Metabolic, and Inflammatory Profiles and Endometrial Cancer Risk Within the EPIC Cohort—A Factor Analysis

A Western lifestyle characterized by physical inactivity and excess weight is associated with a number of metabolic and hormonal dysregulations, including increased circulating estrogen levels, hyperinsulinemia, hyperglycemia, and chronic inflammation. The same hormonal and metabolic axes might mediate the association between this lifestyle and the development of endometrial cancer. Using data collected within the European Prospective Investigation into Cancer and Nutrition (EPIC), a prospective cohort study carried out in 10 European countries during 1992-2000, we conducted a factor analysis to delineate important components that summarize the variation explained by a set of biomarkers and to examine their association with endometrial cancer risk. Prediagnostic levels of testosterone, androstenedione, dehydroepiandrosterone sulfate, sex hormone-binding globulin, estrone, estradiol, C-peptide, insulin-like growth factor-binding proteins 1 and 2, adiponectin, high- and low-density lipoprotein cholesterol, glucose, triglycerides, tumor necrosis factor (TNF) α, soluble TNF receptors 1 and 2, C-reactive protein, interleukin-6, and interleukin-1 receptor antagonist were measured in 233 incident endometrial cancer cases and 446 matched controls. Factor analysis identified 3 components associated with postmenopausal endometrial cancer risk that could be labeled insulin resistance/metabolic syndrome, steroids, and inflammation factors. A fourth component, lipids, was not significantly associated with endometrial cancer. In conclusion, besides the well-known associations of risk with sex hormones and insulin-regulated physiological axes, our data further support the hypothesis that inflammation factors play a role in endometrial carcinogenesis.

Consumption of fish and meats and risk of hepatocellular carcinoma: the European Prospective Investigation into Cancer and Nutrition (EPIC)

BACKGROUNDnWhile higher intake of fish and lower consumption of red/processed meats have been suggested to play a protective role in the etiology of several cancers, prospective evidence for hepatocellular carcinoma (HCC) is limited, particularly in Western European populations.nnnMETHODSnThe associations of fish and meats with HCC risk were analyzed in the EPIC cohort. Between 1992 and 2010, 191 incident HCC were identified among 477 206 participants. Baseline diet was assessed using validated dietary questionnaires. A single 24-h diet recall from a cohort subsample was used for calibration. Multivariable proportional hazard regression was utilized to estimate hazard ratios (HR) and 95% confidence intervals (CI). In a nested case-control subset (HCC = 122), HBV/HCV status and liver function biomarkers were measured.nnnRESULTSnHCC risk was inversely associated with intake of total fish (per 20 g/day increase, HR = 0.83, 95% CI 0.74-0.95 and HR = 0.80, 95% CI 0.69-0.97 before and after calibration, respectively). This inverse association was also suggested after adjusting for HBV/HCV status and liver function score (per 20-g/day increase, RR = 0.86, 95% CI 0.66-1.11 and RR = 0.74, 95% CI 0.50-1.09, respectively) in a nested case-control subset. Intakes of total meats or subgroups of red/processed meats, and poultry were not associated with HCC risk.nnnCONCLUSIONSnIn this large European cohort, total fish intake is associated with lower HCC risk.

Meat and fish consumption and risk of pancreatic cancer: results from the European Prospective Investigation into Cancer and Nutrition.

Pancreatic cancer is the fourth most common cause of cancer death worldwide with large geographical variation, which implies the contribution of diet and lifestyle in its etiology. We examined the association of meat and fish consumption with risk of pancreatic cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC). A total of 477,202 EPIC participants from 10 European countries recruited between 1992 and 2000 were included in our analysis. Until 2008, 865 nonendocrine pancreatic cancer cases have been observed. Calibrated relative risks (RRs) and 95% confidence intervals (CIs) were computed using multivariable‐adjusted Cox hazard regression models. The consumption of red meat (RR per 50 g increase per day = 1.03, 95% CI = 0.93–1.14) and processed meat (RR per 50 g increase per day = 0.93, 95% CI = 0.71–1.23) were not associated with an increased pancreatic cancer risk. Poultry consumption tended to be associated with an increased pancreatic cancer risk (RR per 50 g increase per day = 1.72, 95% CI = 1.04–2.84); however, there was no association with fish consumption (RR per 50 g increase per day = 1.22, 95% CI = 0.92–1.62). Our results do not support the conclusion of the World Cancer Research Fund that red or processed meat consumption may possibly increase the risk of pancreatic cancer. The positive association of poultry consumption with pancreatic cancer might be a chance finding as it contradicts most previous findings.

Mitochondrial DNA copy number and future risk of B-cell lymphoma in a nested case-control study in the prospective EPIC cohort

It has been suggested that mitochondrial dysfunction and DNA damage are involved in lymphomagenesis. Increased copy number of mitochondrial DNA (mtDNA) as a compensatory mechanism of mitochondrial dysfunction previously has been associated with B-cell lymphomas, in particular chronic lymphocytic leukemia (CLL). However, current evidence is limited and based on a relatively small number of cases. Using a nested case-control study, we extended these findings with a focus on subtype-specific analyses. Relative mtDNA copy number was measured in the buffy coat of prospectively collected blood of 469 lymphoma cases and 469 matched controls. The association between mtDNA copy number and the risk of developing lymphoma and histologic subtypes was examined using logistic regression models. We found no overall association between mtDNA and risk of lymphoma. Subtype analyses revealed significant increased risks of CLL (n = 102) with increasing mtDNA copy number (odds ratio = 1.34, 1.44, and 1.80 for quartiles 2-4, respectively; P trend = .001). mtDNA copy number was not associated with follow-up time, suggesting that this observation is not strongly influenced by indolent disease status. This study substantially strengthens the evidence that mtDNA copy number is related to risk of CLL and supports the importance of mitochondrial dysfunction as a possible mechanistic pathway in CLL ontogenesis.

Dietary fibre intake and ischaemic heart disease mortality: the European Prospective Investigation into Cancer and Nutrition-Heart study

Background/objectives:Evidence from prospective studies is consistent in showing an inverse association between dietary fibre intake and risk of ischaemic heart disease (IHD), but whether dietary fibre from various food sources differ in their effect on IHD risk is less clear. The objective of this study was to assess the associations of total and food sources of dietary fibre with IHD mortality in the European Prospective Investigation into Cancer and Nutrition-Heart study.Subjects/methods:Participants were 306u2009331 men and women from eight European countries. Dietary fibre intake was assessed using centre or country-specific diet questionnaires and calibrated using a 24-h diet recall.Results:After an average follow-up of 11.5 years, there were 2381 IHD deaths among participants without cardiovascular disease at baseline. The calibrated intake of dietary fibre was inversely related with IHD mortality; each 10u2009g/day was associated with a 15% lower risk (relative risk (RR) 0.85; 95% confidence interval (CI): 0.73–0.99, P=0.031). There was no difference in the associations of the individual food sources of dietary fibre with the risk of IHD mortality; RR for each 5u2009g/day higher cereal fibre intake was 0.91 (CI: 0.82–1.01), RR for each 2.5u2009g/day fruit fibre intake was 0.94 (CI: 0.88–1.01) and RR for each 2.5u2009g/day vegetable fibre intake was 0.90 (95% CI: 0.76–1.07).Conclusion:A higher consumption of dietary fibre is associated with a lower risk of fatal IHD with no clear difference in the association with IHD for fibre from cereals, fruits or vegetables.

Consumption of meat and fish and risk of lung cancer: results from the European Prospective Investigation into Cancer and Nutrition

Evidence from case–control studies, but less so from cohort studies, suggests a positive association between meat intake and risk of lung cancer. Therefore, this association was evaluated in the frame of the European Prospective Investigation into Cancer and Nutrition, EPIC. Data from 478,021 participants, recruited from 10 European countries, who completed a dietary questionnaire in 1992–2000 were evaluated; 1,822 incident primary lung cancer cases were included in the present evaluation. Relative risk estimates were calculated for categories of meat intake using multi-variably adjusted Cox proportional hazard models. In addition, the continuous intake variables were calibrated by means of 24-h diet recall data to account for part of the measurement error. There were no consistent associations between meat consumption and the risk of lung cancer. Neither red meat (RRxa0=xa01.06, 95% CI 0.89–1.27 per 50xa0g intake/day; calibrated model) nor processed meat (RRxa0=xa01.13, 95% CI 0.95–1.34 per 50xa0g/day; calibrated model) was significantly related to an increased risk of lung cancer. Also, consumption of white meat and fish was not associated with the risk of lung cancer. These findings do not support the hypothesis that a high intake of red and processed meat is a risk factor for lung cancer.

Prediagnostic telomere length and risk of B-cell lymphoma—Results from the EPIC cohort study

Recent epidemiological investigations have reported on the association between telomere length (TL) and a number of malignancies, including B‐cell lymphoma (BCL). The reported results for BCLs are however inconsistent. We carried out a nested case–control study to determine whether TL is associated with future risk of BCL. Using quantitative polymerase chain reaction, the relative TL (i.e. the ratio of telomere repeat copy number to single gene copy number) was measured in mononuclear cell DNA of prediagnostic peripheral blood samples of 464 lymphoma cases and 464 matched controls (median time between blood collection and diagnosis, 4.6 years). Conditional logistic regression was used to analyze the association between TL and the risk of developing lymphoma and histologic subtypes. TL was significantly longer in cases compared to controls (p = 0.01). Multivariable models showed a significantly increased risk of BCL [odds ratio (OR) = 1.66, 1.80 and 3.20 for quartiles 2–4, respectively, p‐trend = 0.001], diffuse large B‐cell lymphoma (DLBCL) (OR = 1.20, 2.48 and 2.36 for quartiles 2–4, respectively, p‐trend = 0.03) and follicular lymphoma (FL) (OR = 1.39, 1.90 and 2.69 for quartiles 2–4, respectively, p‐trend = 0.02) with increasing TL. This study suggests an association between longer leucocyte TL and increased risk of BCL which was most pronounced for DLBCL and FL.

Anthropometric characteristics and risk of lymphoid and myeloid leukemia in the European Prospective Investigation into Cancer and Nutrition (EPIC)

PurposeOverweight and obesity have been suggested as a risk factor for leukemia. Impaired immune function associated with obesity, increased insulin-like growth factor-I activity and stimulating effects of leptin suggest a possible biological link between anthropometric measures and leukemia. However, evidence from epidemiological studies has been inconsistent. We examined the potential association between prospective measurements of body size and risk of leukemia among participants of the European Prospective Investigation into Cancer and Nutrition (EPIC).MethodsDuring follow-up (meanxa0=xa011.52xa0years, standard deviationxa0=xa02.63), 671 leukemia (lymphoid leukemiaxa0=xa050.1xa0%, myeloid leukemiaxa0=xa043.2xa0%) cases were identified. Anthropometric measures including weight, height, body mass index (BMI), waist circumference (WC), hip circumference, and waist-to-hip ratio (WHR) were measured. Cox proportional hazard models were used to explore the association between anthropometric measures and risk of leukemia.ResultsNo associations were observed between anthropometric measures and total leukemia, and lymphoid leukemia. Risk of myeloid leukemia significantly increased for higher categories of BMI and WC among women. Analyses by subtype of myeloid leukemia showed an increased risk of acute myeloid leukemia (AML) for higher categories of WHR among women. This association seemed to be reversed for chronic myeloid leukemia. No association between anthropometric measures and myeloid leukemia were observed among men except an increased risk of AML with height.ConclusionThe study showed no associations between anthropometric measures and total leukemia, and lymphoid leukemia among men and women. A possible association between BMI as general obesity and WC as abdominal obesity and increased risk of myeloid leukemia among women were observed.

Dietary Intakes and Risk of Lymphoid and Myeloid Leukemia in the European Prospective Investigation into Cancer and Nutrition (EPIC)

The etiology of leukemias cannot entirely be explained by known risk factors, including ionizing radiation, benzene exposure, and infection with human T cell leukemia virus. A number of studies suggested that diet influences the risk of adult leukemias. However, results have been largely inconsistent. We examined the potential association between dietary factors and risk of leukemias among participants of the European Prospective Investigation into Cancer and Nutrition study. Among the 477,325 participants with mean follow-up of 11.34 yr (SD = 2.47), 773 leukemias (373 and 342 cases of lymphoid and myeloid leukemia, respectively) were identified. Diet over the previous 12 mo was assessed at baseline using a validated country-specific dietary questionnaire. Cox proportional hazards regression was used to explore the association between dietary factors that have previously been associated with leukemia risk, including red and processed meat, poultry, offal, fish, dairy products, vegetables, fruits, and seeds/nuts, and risk of both lymphoid and myeloid leukemias. No significant associations were observed between dietary measures and total, lymphoid, and myeloid leukemias. Additional subtype analyses showed no dietary association with risk of major subtypes of leukemias. In summary, this study did not support a possible link between selected dietary factors and risk of leukemias.