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- 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. |
- 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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| 3. |
- 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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| 7. |
- Feitosa, Mary F., et al.
(författare)
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Novel genetic associations for blood pressure identified via gene-alcohol interaction in up to 570K individuals across multiple ancestries
- 2018
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Ingår i: PLOS ONE. - : Public library science. - 1932-6203. ; 13:6
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Tidskriftsartikel (refereegranskat)abstract
- Heavy alcohol consumption is an established risk factor for hypertension; the mechanism by which alcohol consumption impact blood pressure (BP) regulation remains unknown. We hypothesized that a genome-wide association study accounting for gene-alcohol consumption interaction for BP might identify additional BP loci and contribute to the understanding of alcohol-related BP regulation. We conducted a large two-stage investigation incorporating joint testing of main genetic effects and single nucleotide variant (SNV)-alcohol consumption interactions. In Stage 1, genome-wide discovery meta-analyses in approximate to 131 K individuals across several ancestry groups yielded 3,514 SNVs (245 loci) with suggestive evidence of association (P <1.0 x 10(-5)). In Stage 2, these SNVs were tested for independent external replication in individuals across multiple ancestries. We identified and replicated (at Bonferroni correction threshold) five novel BP loci (380 SNVs in 21 genes) and 49 previously reported BP loci (2,159 SNVs in 109 genes) in European ancestry, and in multi-ancestry meta-analyses (P < 5.0 x 10(-8)). For African ancestry samples, we detected 18 potentially novel BP loci (P< 5.0 x 10(-8)) in Stage 1 that warrant further replication. Additionally, correlated meta-analysis identified eight novel BP loci (11 genes). Several genes in these loci (e.g., PINX1, GATA4, BLK, FTO and GABBR2 have been previously reported to be associated with alcohol consumption. These findings provide insights into the role of alcohol consumption in the genetic architecture of hypertension.
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| 8. |
- Fiskesund, Roland, et al.
(författare)
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Low levels of antibodies against phosphorylcholine predict development of stroke in a population-based study from northern Sweden
- 2010
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Ingår i: Stroke. - 0039-2499 .- 1524-4628. ; 41:4, s. 607-612
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Natural immunoglobulin M antibodies specific for phosphorylcholine (anti-PC) have been implicated in atherosclerosis. We have shown previously that high levels of anti-PC predict a slower progression of atherosclerosis in humans and that low levels of anti-PC are associated with higher risk for cardiovascular disease. Here we determine the association between anti-PC and the incidence of stroke. METHODS: Using a nested case control study design, we examined 227 incident cases (125 men and 102 women) of first-time stroke and 455 age- and sex-matched controls identified during a 13-year time period (1985 to 1999) within the population-based cohorts of the Västerbotten Intervention Project (VIP) and the World Health Organization Monitoring Trends and Determinants in Cardiovascular Disease (WHO MONICA) project in Northern Sweden. Odds ratios of stroke with 95% CIs with adjustments for age, gender, smoking, serum cholesterol, diabetes, body mass index, and blood pressure were determined. Anti-PC levels were measured using ELISA. RESULTS: A significant association between low levels of anti-PC at baseline and incident stroke was seen for the whole group of anti-PC levels below the 30th percentile (multivariately adjusted odds ratio, 1.62; CI, 1.11 to 2.35). Analyses of gender-specific associations indicated fairly strong associations for females, especially at the lowest 30th percentile (multivariately adjusted odds ratio, 2.65; CI, 1.41 to 4.95). No associations were noted for men. CONCLUSION: Low anti-PC is a novel independent risk marker for development of stroke. Measurements of anti-PC could be used to identify immunodeficient subjects at an increased risk for stroke. The possibility that such subjects might be targets for novel modes of treatment such as immunotherapies deserves further investigation.
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| 9. |
- Försti, A, et al.
(författare)
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Polymorphisms in the genes of the urokinase plasminogen activation system in relation to colorectal cancer
- 2007
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Ingår i: Annals of Oncology. - : Oxford University Press. - 0923-7534 .- 1569-8041. ; 18:12, s. 1990-1994
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Tidskriftsartikel (refereegranskat)abstract
- Background: Extracellular matrix degradation, mediated by the urokinase plasminogen activation (uPA) system, is a critical step in tumor invasion and metastasis. High tumor levels of uPA and its inhibitor PAI-1 have been correlated with poor cancer prognosis. We examined four single nucleotide polymorphisms (SNPs) with a potential effect on expression of genes in the uPA system for their role in colorectal cancer susceptibility and prognosis.Patients and methods: We genotyped the SNPs in 308 Swedish incident colorectal cancer patients with up to 16 years of follow-up and in 585 age- and sex-matched controls. We evaluated the associations between genotypes and colorectal cancer and Dukes' stage. Survival probabilities were compared between different subgroups.Results: Patients with PAI-1 –675 5G/5G genotype had better survival than patients with 4G/4G or 4G/5G genotypes when they had Dukes' stage A or B tumors (P = 0.023 and P = 0.015, respectively). No statistically significant association was observed between the SNPs and the risk of colorectal cancer or Dukes' stage.Conclusions: Our results suggest a role for the PAI-1 genotype in colorectal cancer prognosis, but further studies are needed to evaluate the impact of our finding in the clinic.
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| 10. |
- Hvidtfeldt, Ulla A., et al.
(författare)
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Alcohol Intake and Risk of Coronary Heart Disease in Younger, Middle-Aged, and Older Adults
- 2010
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Ingår i: Circulation. - : LIPPINCOTT WILLIAMS & WILKINS. - 0009-7322 .- 1524-4539. ; 121:14, s. 1589-1597
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Tidskriftsartikel (refereegranskat)abstract
- Background-Light to moderate alcohol consumption is associated with a reduced risk of coronary heart disease. This protective effect of alcohol, however, may be confined to middle-aged or older individuals. Coronary heart disease incidence is low in men <40 years of age and in women <50 years of age; for this reason, study cohorts rarely have the power to investigate the effects of alcohol on coronary heart disease risk in younger adults. This study examined whether the beneficial effect of alcohol on coronary heart disease depends on age. Methods and Results-In this pooled analysis of 8 prospective studies from North America and Europe including 192 067 women and 74 919 men free of cardiovascular diseases, diabetes, and cancers at baseline, average daily alcohol intake was assessed at baseline with a food frequency or diet history questionnaire. An inverse association between alcohol and risk of coronary heart disease was observed in all age groups; hazard ratios among moderately drinking men (5.0 to 29.9 g/d) 39 to 50, 50 to 59, and >= 60 years of age were 0.58 (95% confidence interval [CI], 0.36 to 0.93), 0.72 (95% CI, 0.60 to 0.86), and 0.85 (95% CI, 0.75 to 0.97) compared with abstainers. However, the analyses indicated a smaller incidence rate difference between abstainers and moderate consumers in younger adults (incidence rate difference, 45 per 100 000; 90% CI, 8 to 84) than in middle-aged (incidence rate difference, 64 per 100 000; 90% CI, 24 to 102) and older (incidence rate difference, 89 per 100 000; 90% CI, 44 to 140) adults. Similar results were observed in women. Conclusion-Alcohol is also associated with a decreased risk of coronary heart disease in younger adults; however, the absolute risk was small compared with middle-aged and older adults. (Circulation. 2010; 121: 1589-1597.)
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