| 1. |
- Burgess, S., et al.
(författare)
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Bayesian methods for meta-analysis of causal relationships estimated using genetic instrumental variables
- 2010
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Ingår i: Statistics in medicine. - : Wiley. - 1097-0258 .- 0277-6715. ; 29:12, s. 1298-311
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Tidskriftsartikel (refereegranskat)abstract
- Genetic markers can be used as instrumental variables, in an analogous way to randomization in a clinical trial, to estimate the causal relationship between a phenotype and an outcome variable. Our purpose is to extend the existing methods for such Mendelian randomization studies to the context of multiple genetic markers measured in multiple studies, based on the analysis of individual participant data. First, for a single genetic marker in one study, we show that the usual ratio of coefficients approach can be reformulated as a regression with heterogeneous error in the explanatory variable. This can be implemented using a Bayesian approach, which is next extended to include multiple genetic markers. We then propose a hierarchical model for undertaking a meta-analysis of multiple studies, in which it is not necessary that the same genetic markers are measured in each study. This provides an overall estimate of the causal relationship between the phenotype and the outcome, and an assessment of its heterogeneity across studies. As an example, we estimate the causal relationship of blood concentrations of C-reactive protein on fibrinogen levels using data from 11 studies. These methods provide a flexible framework for efficient estimation of causal relationships derived from multiple studies. Issues discussed include weak instrument bias, analysis of binary outcome data such as disease risk, missing genetic data, and the use of haplotypes.
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| 2. |
- Tjonneland, A., et al.
(författare)
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Linoleic acid, a dietary n-6 polyunsaturated fatty acid, and the aetiology of ulcerative colitis: a nested case-control study within a European prospective cohort study
- 2009
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Ingår i: Gut. - : BMJ. - 1468-3288 .- 0017-5749. ; 58:12, s. 1606-1611
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Dietary linoleic acid, an n-6 polyunsaturated fatty acid, is metabolised to arachidonic acid, a component of colonocyte membranes. Metabolites of arachidonic acid have pro-inflammatory properties and are increased in the mucosa of patients with ulcerative colitis. The aim of this investigation was to conduct the first prospective cohort study investigating if a high dietary intake of linoleic acid increases the risk of developing incident ulcerative colitis. Design and setting: Dietary data from food frequency questionnaires were available for 203 193 men and women aged 30-74 years, resident in the UK, Sweden, Denmark, Germany or Italy and participating in a prospective cohort study, the European Prospective Investigation into Cancer and Nutrition (EPIC). These participants were followed up for the diagnosis of ulcerative colitis. Each case was matched with four controls and the risk of disease calculated by quartile of intake of linoleic acid adjusted for gender, age, smoking, total energy intake and centre. Results: A total of 126 participants developed ulcerative colitis (47% women) after a median follow-up of 4.0 years (range, 1.7-11.3 years). The highest quartile of intake of linoleic acid was associated with an increased risk of ulcerative colitis (odds ratio (OR) = 2.49, 95% confidence interval (CI) = 1.23 to 5.07, p = 0.01) with a significant trend across quartiles (OR = 1.32 per quartile increase, 95% CI = 1.04 to 1.66, p = 0.02 for trend). Conclusions: The data support a role for dietary linoleic acid in the aetiology of ulcerative colitis. An estimated 30% of cases could be attributed to having dietary intakes higher than the lowest quartile of linoleic acid intake.
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| 3. |
- Andersson, Kristin, et al.
(författare)
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The interface of population-based cancer registries and biobanks in etiological and clinical research : current and future perspectives
- 2010
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Ingår i: Acta Oncologica. - 0284-186X .- 1651-226X. ; 49:8, s. 1227-1234
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The availability of quality assured, population-based cancer registries and biobanks with high quality samples makes it possible to conduct research on large samples sets with long follow-up within a reasonable time frame. Defined quality for both cancer registries and biobanks is essential for enabling high quality biobank-based research. Recent networking projects have brought these infrastructures together to promote the combined use of cancer registries and biobanks in cancer research.MATERIALS AND METHODS: In this report we review the current status and future perspectives of cancer registries and biobanks and how the interface between them should be developed to optimally further cancer research.RESULTS AND DISCUSSION: Major conclusions for future improvements are that the research exploiting cancer registries and biobanks, and the research that is building and optimising the infrastructure, should evolve together for maximally relevant progress. Population-based and sustainable biobanks that continuously and consecutively store all samples ("Biological registries") under strict quality control are needed. There is also a need for increased education, information and visibility of the interdisciplinary sciences required for optimal exploitation of these resources.
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| 4. |
- Bjørge, Tone, et al.
(författare)
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Metabolic syndrome and breast cancer in the me-can (metabolic syndrome and cancer) project.
- 2010
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Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - 1055-9965 .- 1538-7755. ; 19:7, s. 1737-1745
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Few studies have assessed the metabolic syndrome (MetS) as an entity in relation to breast cancer risk, and results have been inconsistent. We aimed to examine the association between MetS factors (individually and combined) and risk of breast cancer incidence and mortality. METHODS: Two hundred ninety thousand women from Austria, Norway, and Sweden were enrolled during 1974-2005, with measurements of height, weight, blood pressure, and levels of glucose, cholesterol, and triglycerides. Relative risks (RR) of breast cancer were estimated using Cox proportional hazards regression for each MetS factor in quintiles and for standardized levels (z-scores) and for a composite z-score for the MetS. RESULTS: There were 4,862 incident cases of breast cancer and 633 deaths from breast cancer identified. In women below age 50, there was a decreased risk of incident cancer for the MetS (per 1-unit increment of z-score; RR, 0.83; 95% confidence interval, 0.76-0.90) as well as for the individual factors (except for glucose). The lowest risks were seen among the heaviest women. In women above age 60, there was an increased risk of breast cancer mortality for the MetS (RR, 1.23; 95% confidence interval, 1.04-1.45) and for blood pressure and glucose. The strongest association with mortality was seen for increased glucose concentrations. CONCLUSIONS: The MetS was associated with a decreased risk of incident breast cancer in women below age 50 with high body mass index, and with an increased risk of breast cancer mortality in women above 60. IMPACT: Lifestyle interventions as recommended for cardiovascular disease prevention may be of value to prevent breast cancer mortality in postmenopausal women.
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| 5. |
- Boffetta, Paolo, et al.
(författare)
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Fruit and vegetable intake and overall cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC).
- 2010
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 1460-2105 .- 0027-8874. ; 102:8, s. 529-537
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: It is widely believed that cancer can be prevented by high intake of fruits and vegetables. However, inconsistent results from many studies have not been able to conclusively establish an inverse association between fruit and vegetable intake and overall cancer risk. METHODS: We conducted a prospective analysis of the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort to assess relationships between intake of total fruits, total vegetables, and total fruits and vegetables combined and cancer risk during 1992-2000. Detailed information on the dietary habit and lifestyle variables of the cohort was obtained. Cancer incidence and mortality data were ascertained, and hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using multivariable Cox regression models. Analyses were also conducted for cancers associated with tobacco and alcohol after stratification for tobacco smoking and alcohol drinking. RESULTS: Of the initial 142 605 men and 335 873 women included in the study, 9604 men and 21 000 women were identified with cancer after a median follow-up of 8.7 years. The crude cancer incidence rates were 7.9 per 1000 person-years in men and 7.1 per 1000 person-years in women. Associations between reduced cancer risk and increased intake of total fruits and vegetables combined and total vegetables for the entire cohort were similar (200 g/d increased intake of fruits and vegetables combined, HR = 0.97, 95% CI = 0.96 to 0.99; 100 g/d increased intake of total vegetables, HR = 0.98, 95% CI = 0.97 to 0.99); intake of fruits showed a weaker inverse association (100 g/d increased intake of total fruits, HR = 0.99, 95% CI = 0.98 to 1.00). The reduced risk of cancer associated with high vegetable intake was restricted to women (HR = 0.98, 95% CI = 0.97 to 0.99). Stratification by alcohol intake suggested a stronger reduction in risk in heavy drinkers and was confined to cancers caused by smoking and alcohol. CONCLUSIONS: A very small inverse association between intake of total fruits and vegetables and cancer risk was observed in this study. Given the small magnitude of the observed associations, caution should be applied in their interpretation.
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| 6. |
- Buchner, F. L., et al.
(författare)
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Fruits and vegetables consumption and the risk of histological subtypes of lung cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC)
- 2010
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Ingår i: Cancer Causes and Control. - : Springer Science and Business Media LLC. - 1573-7225 .- 0957-5243. ; 21:3, s. 357-371
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Tidskriftsartikel (refereegranskat)abstract
- Objective To examine the association between fruit and vegetable consumption and risk of different histological subtypes of lung cancer among participants of the European Prospective Investigation into Cancer and Nutrition study. Methods Multivariable Cox proportional hazard models were used to analyze the data. A calibration study in a subsample was used to reduce dietary measurement errors. Results During a mean follow-up of 8.7 years, 1,830 incident cases of lung cancer (574 adenocarcinoma, 286 small cell, 137 large cell, 363 squamous cell, 470 other histologies) were identified. In line with our previous conclusions, we found that after calibration a 100 g/day increase in fruit and vegetables consumption was associated with a reduced lung cancer risk (HR 0.94; 95% CI 0.89-0.99). This was also seen among current smokers (HR 0.93; 95% CI 0.90-0.97). Risks of squamous cell carcinomas in current smokers were reduced for an increase of 100 g/day of fruit and vegetables combined (HR 0.85; 95% CI 0.76-0.94), while no clear effects were seen for the other histological subtypes. Conclusion We observed inverse associations between the consumption of vegetables and fruits and risk of lung cancer without a clear effect on specific histological subtypes of lung cancer. In current smokers, consumption of vegetables and fruits may reduce lung cancer risk, in particular the risk of squamous cell carcinomas.
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| 7. |
- Büchner, Frederike L, et al.
(författare)
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Variety in fruit and vegetable consumption and the risk of lung cancer in the European prospective investigation into cancer and nutrition
- 2010
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Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - : American Association for Cancer Research. - 1055-9965 .- 1538-7755. ; 19:9, s. 2278-2286
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: We investigated whether a varied consumption of vegetables and fruits is associated with lower lung cancer risk in the European Prospective Investigation into Cancer and Nutrition study. METHODS: After a mean follow-up of 8.7 years, 1,613 of 452,187 participants with complete information were diagnosed with lung cancer. Diet diversity scores (DDS) were used to quantify the variety in fruit and vegetable consumption. Multivariable proportional hazards models were used to assess the associations between DDS and lung cancer risk. All models were adjusted for smoking behavior and the total consumption of fruit and vegetables. RESULTS: With increasing variety in vegetable subgroups, risk of lung cancer decreases [hazard ratios (HR), 0.77; 95% confidence interval (CI), 0.64-0.94 highest versus lowest quartile; P trend = 0.02]. This inverse association is restricted to current smokers (HR, 0.73; 95% CI, 0.57-0.93 highest versus lowest quartile; P trend = 0.03). In continuous analyses, in current smokers, lower risks were observed for squamous cell carcinomas with more variety in fruit and vegetable products combined (HR/two products, 0.88; 95% CI, 0.82-0.95), vegetable subgroups (HR/subgroup, 0.88; 95% CI, 0.79-0.97), vegetable products (HR/two products, 0.87; 95% CI, 0.79-0.96), and fruit products (HR/two products, 0.84; 95% CI, 0.72-0.97). CONCLUSION: Variety in vegetable consumption was inversely associated with lung cancer risk among current smokers. Risk of squamous cell carcinomas was reduced with increasing variety in fruit and/or vegetable consumption, which was mainly driven by the effect in current smokers. IMPACT: Independent from quantity of consumption, variety in fruit and vegetable consumption may decrease lung cancer risk.
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| 8. |
- Büchner, Frederike L, et al.
(författare)
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Variety in vegetable and fruit consumption and risk of bladder cancer in the European prospective investigation into cancer and nutrition
- 2011
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 128:12, s. 2971-2979
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Tidskriftsartikel (refereegranskat)abstract
- Recent research does not show an association between fruit and vegetable consumption and bladder cancer risk. None of these studies investigated variety in fruit and vegetable consumption, which may capture different aspects of consumption. We investigated whether a varied consumption of vegetables and fruits is associated with bladder cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Detailed data on food consumption and complete follow-up for cancer incidence were available for 452,185 participants, who were recruited from ten European countries. After a mean follow-up of 8.7 years, 874 participants were diagnosed with bladder cancer. Diet diversity scores (DDSs) were used to quantify the variety in fruit and vegetable consumption. Multivariable Cox proportional hazard models were used to assess the effect of the DDSs on bladder cancer risk. There was no evidence of a statistically significant association between bladder cancer risk and any of the DDSs when these scores were considered as continuous covariates. However, the hazard ratio (HR) for the highest tertile of the DDS for combined fruit and vegetable consumption was marginally significant compared to the lowest (HR = 1.30, 95% confidence interval: 1.00-1.69, p-trend = 0.05). In EPIC, there is no clear association between a varied fruit and vegetable consumption and bladder cancer risk. This finding provides further evidence for the absence of any strong association between fruit and vegetable consumption as measured by a food frequency questionnaire and bladder cancer risk.
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| 9. |
- Chan, Simon S. M., et al.
(författare)
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Body Mass Index and the Risk for Crohn's Disease and Ulcerative Colitis : Data From a European Prospective Cohort Study (The IBD in EPIC Study)
- 2013
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Ingår i: American Journal of Gastroenterology. - New York, NY, USA : Nature Publishing Group. - 0002-9270 .- 1572-0241. ; 108:4, s. 575-582
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Obesity is associated with a proinflammatory state that may be involved in the etiology of inflammatory bowel disease (IBD), for which there are plausible biological mechanisms. Our aim was to perform the first prospective cohort study investigating if there is an association between obesity and the development of incident IBD. METHODS: A total of 300,724 participants were recruited into the European Prospective Investigation into Cancer and Nutrition study. At recruitment, anthropometric measurements of height and weight plus physical activity and total energy intake from validated questionnaires were recorded. The cohort was monitored identifying participants who developed either Crohn's disease (CD) or ulcerative colitis (UC). Each case was matched with four controls and conditional logistic regression used to calculate odds ratios (ORs) for body mass index (BMI) adjusted for smoking, energy intake, and physical activity. RESULTS: In the cohort, 177 participants developed incident UC and 75 participants developed incident CD. There were no associations with the four higher categories of BMI compared with a normal BMI for UC (P-trend = 0.36) or CD (P-trend = 0.83). The lack of associations was consistent when BMI was analyzed as a continuous or binary variable (BMI 18.5 <25.0 vs. >= 25 kg/m(2)). Physical activity and total energy intake, factors that influence BMI, did not show any association with UC (physical activity, P-trend = 0.79; total energy intake, P-trend = 0.18) or CD (physical activity, P-trend = 0.42; total energy, P-trend = 0.11). CONCLUSIONS: Obesity as measured by BMI is not associated with the development of incident UC or CD. Alternative measures of obesity are required to further investigate the role of obesity in the development of incident IBD.
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| 10. |
- Chan, Simon S. M., et al.
(författare)
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Carbohydrate Intake in the Etiology of Crohn's Disease and Ulcerative Colitis
- 2014
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Ingår i: Inflammatory Bowel Diseases. - : Lippincott Williams & Wilkins. - 1078-0998 .- 1536-4844. ; 20:11, s. 2013-2021
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Tidskriftsartikel (refereegranskat)abstract
- Background: Diet may have a role in the etiology of inflammatory bowel disease. In previous studies, the associations between increased intakes of carbohydrates, sugar, starch, and inflammatory bowel disease are inconsistent. However, few prospective studies have investigated the associations between these macronutrients and incident Crohn's disease (CD) or ulcerative colitis (UC). Methods: A total of 401,326 men and women were recruited between 1991 and 1998. At recruitment, dietary intakes of carbohydrate, sugar, and starch were measured using validated food frequency questionnaires. The cohort was monitored identifying participants who developed incident CD or UC. Cases were matched with 4 controls, and odds ratios were calculated for quintiles of total carbohydrate, sugar, and starch intakes adjusted for total energy intake, body mass index, and smoking. Results: One hundred ten participants developed CD, and 244 participants developed UC during follow-up. The adjusted odds ratio for the highest versus the lowest quintiles of total carbohydrate intake for CD was 0.87, 95% CI = 0.24 to 3.12 and for UC 1.46, 95% CI = 0.62 to 3.46, with no significant trends across quintiles for either (CD, P-trend = 0.70; UC, P-trend = 0.41). Similarly, no associations were observed with intakes of total sugar (CD, P-trend = 0.50; UC, P-trend = 0.71) or starch (CD, P-trend = 0.69; UC, P-trend = 0.17). Conclusions: The lack of associations with these nutrients is in agreement with many case-control studies that have not identified associations with CD or UC. As there is biological plausibility for how specific carbohydrates could have an etiological role in inflammatory bowel disease, future epidemiological work should assess individual carbohydrates, although there does not seem to be a macronutrient effect.
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