| 1. |
- Almqvist, Catarina, et al.
(author)
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LifeGene - A large prospective population-based study of global relevance
- 2011
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In: European Journal of Epidemiology. - Stockholm : Springer Science and Business Media LLC. - 0393-2990 .- 1573-7284. ; 26:1, s. 67-77
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Journal article (peer-reviewed)abstract
- Studying gene-environment interactions requires that the amount and quality of the lifestyle data is comparable to what is available for the corresponding genomic data. Sweden has several crucial prerequisites for comprehensive longitudinal biomedical research, such as the personal identity number, the universally available national health care system, continuously updated population and health registries and a scientifically motivated population. LifeGene builds on these strengths to bridge the gap between basic research and clinical applications with particular attention to populations, through a unique design in a research-friendly setting. LifeGene is designed both as a prospective cohort study and an infrastructure with repeated contacts of study participants approximately every 5 years. Index persons aged 18-45 years old will be recruited and invited to include their household members (partner and any children). A comprehensive questionnaire addressing cutting-edge research questions will be administered through the web with short follow-ups annually. Biosamples and physical measurements will also be collected at baseline, and re-administered every 5 years thereafter. Event-based sampling will be a key feature of LifeGene. The household-based design will give the opportunity to involve young couples prior to and during pregnancy, allowing for the first study of children born into cohort with complete pre-and perinatal data from both the mother and father. Questions and sampling schemes will be tailored to the participants' age and life events. The target of LifeGene is to enrol 500,000 Swedes and follow them longitudinally for at least 20 years.
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| 2. |
- Byrnes, Andrea, et al.
(author)
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Gene expression in peripheral blood leukocytes in monozygotic twins discordant for chronic fatigue : no evidence of a biomarker
- 2009
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 4:6, s. e5805-
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Journal article (peer-reviewed)abstract
- BACKGROUND: Chronic fatiguing illness remains a poorly understood syndrome of unknown pathogenesis. We attempted to identify biomarkers for chronic fatiguing illness using microarrays to query the transcriptome in peripheral blood leukocytes. METHODS: Cases were 44 individuals who were clinically evaluated and found to meet standard international criteria for chronic fatigue syndrome or idiopathic chronic fatigue, and controls were their monozygotic co-twins who were clinically evaluated and never had even one month of impairing fatigue. Biological sampling conditions were standardized and RNA stabilizing media were used. These methodological features provide rigorous control for bias resulting from case-control mismatched ancestry and experimental error. Individual gene expression profiles were assessed using Affymetrix Human Genome U133 Plus 2.0 arrays. FINDINGS: There were no significant differences in gene expression for any transcript. CONCLUSIONS: Contrary to our expectations, we were unable to identify a biomarker for chronic fatiguing illness in the transcriptome of peripheral blood leukocytes suggesting that positive findings in prior studies may have resulted from experimental bias.
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| 3. |
- Dufva, Ylva Eriksson, et al.
(author)
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Swedish large-scale schizophrenia study : Why do patients and healthy controls participate?
- 2021
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In: Schizophrenia Research. - : Elsevier BV. - 0920-9964 .- 1573-2509. ; 228, s. 360-366
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Journal article (peer-reviewed)abstract
- Insights into determination of study participation are useful for researchers, clinicians and for ethical considerations. Few large-scale genomic studies have involved motives for enrollment, in schizophrenia patients and unaffected controls. In a case-control study with participants recruited nation-wide in Sweden between 2005 and 2010, semi-structured interviews on motives and attitudes towards future studies were explored in 2767 schizophrenia cases and 4466 controls. In qualitative and quantitative analyses, we identified altruism as a major determinant in 84% of the cases and in 97% of the controls. Among pre-defined subcategories of altruism, cases with schizophrenia were more often referring to science for example, 'I want to help science move forward' or 'I want better medications for future generations' in relation to unaffected controls that were more often referring to common humanity such as 'It is my duty and responsibility to help'. In schizophrenia, motives related to personal benefit and social influence were reported by 9% and 5%. We conclude that individuals with schizophrenia frequently report altruistic motives for study participation, almost to the same extent as unaffected controls. In contrast to unfortunate stereotypes, people with schizophrenia wish others to benefit from their experiences with severe mental illness and should not be refrained from participating in genomic research.
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| 4. |
- Evengård, Birgitta, 1952-, et al.
(author)
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The epidemiology of chronic fatigue in the Swedish Twin Registry
- 2005
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In: Psychological Medicine. - 0033-2917 .- 1469-8978. ; 35:9, s. 1317-1326
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Journal article (peer-reviewed)abstract
- CFS-like illness may be more common that previously acknowledged. There is a marked increase in risk by gender. Previous reports that CFS is more prevalent in individuals in certain occupational categories were not confirmed and may have been due to confounding by gender.
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| 5. |
- Forlenza, Michael J, et al.
(author)
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Epidemiology of cancer-related fatigue in the Swedish twin registry
- 2005
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In: Cancer. - : Wiley. - 0008-543X .- 1097-0142. ; 104:9, s. 2022-2031
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Journal article (peer-reviewed)abstract
- A greater proportion of individuals who were listed in a national cancer registry reported experiencing fatigue compared with individuals in the general population.
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| 6. |
- Hannon, Eilis, et al.
(author)
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DNA methylation meta-analysis reveals cellular alterations in psychosis and markers of treatment-resistant schizophrenia
- 2021
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In: eLIFE. - : eLife Sciences Publications. - 2050-084X. ; 10
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Journal article (peer-reviewed)abstract
- We performed a systematic analysis of blood DNA methylation profiles from 4483 participants from seven independent cohorts identifying differentially methylated positions (DMPs) associated with psychosis, schizophrenia, and treatment-resistant schizophrenia. Psychosis cases were characterized by significant differences in measures of blood cell proportions and elevated smoking exposure derived from the DNA methylation data, with the largest differences seen in treatment-resistant schizophrenia patients. We implemented a stringent pipeline to meta-analyze epigenome-wide association study (EWAS) results across datasets, identifying 95 DMPs associated with psychosis and 1048 DMPs associated with schizophrenia, with evidence of colocalization to regions nominated by genetic association studies of disease. Many schizophrenia-associated DNA methylation differences were only present in patients with treatment-resistant schizophrenia, potentially reflecting exposure to the atypical antipsychotic clozapine. Our results highlight how DNA methylation data can be leveraged to identify physiological (e.g., differential cell counts) and environmental (e.g., smoking) factors associated with psychosis and molecular biomarkers of treatment-resistant schizophrenia.
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| 7. |
- Kato, K, et al.
(author)
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A population-based twin study of functional somatic syndromes
- 2009
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In: Psychological Medicine. - : Cambridge University Press. - 0033-2917 .- 1469-8978. ; 39:3, s. 497-505
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Journal article (peer-reviewed)abstract
- BACKGROUND: The mechanisms underlying the co-occurrence of the functional somatic syndromes are largely unknown. No empirical study has explicitly examined how genetic and environmental factors influence the co-morbidity of these syndromes. We aimed to examine how the co-morbidity of functional somatic syndromes is influenced by genetic and environmental factors that are in common to the syndromes. METHOD: A total of 31318 twins in the Swedish Twin Registry aged 41-64 years underwent screening interviews via a computer-assisted telephone system from 1998 to 2002. Four functional somatic syndromes (chronic widespread pain, chronic fatigue, irritable bowel syndrome, and recurrent headache) and two psychiatric disorders (major depression and generalized anxiety disorder) were assessed using structured questions based on standard criteria for each illness in a blinded manner. RESULTS: Multivariate twin analyses revealed that a common pathway model with two latent traits that were shared by the six illnesses fit best to the women's data. One of the two latent traits loaded heavily on the psychiatric disorders, whereas the other trait loaded on all four of the functional somatic syndromes, particularly chronic widespread pain, but not on the psychiatric disorders. All illnesses except the psychiatric disorders were also affected by genetic influences that were specific to each. CONCLUSIONS: The co-occurrence of functional somatic syndromes in women can be best explained by affective and sensory components in common to all these syndromes, as well as by unique influences specific to each of them. The findings clearly suggest a complex view of the multifactorial pathogenesis of these illnesses.
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| 8. |
- Kato, Kenji, et al.
(author)
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Chronic widespread pain and its comorbidities : a population-based study
- 2006
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In: Archives of Internal Medicine. - : American Medical Association (AMA). - 0003-9926 .- 1538-3679. ; 166:15, s. 1649-1654
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Journal article (peer-reviewed)abstract
- Associations between CWP and most comorbidities are mediated by unmeasured genetic and family environmental factors in the general population. The extent of mediation via familial factors is likely to be disorder specific.
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| 9. |
- Kato, Kenji, et al.
(author)
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Importance of genetic influences on chronic widespread pain
- 2006
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In: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 54:5, s. 1682-1686
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Journal article (peer-reviewed)abstract
- Individual differences in the likelihood of developing chronic widespread pain reflect modest genetic influences. There are no significant sex differences in the type or expression of the genes responsible for chronic widespread pain or in the magnitude of the relative importance of these influences on chronic widespread pain.
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| 10. |
- Kato, Kenji, et al.
(author)
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Premorbid predictors of chronic fatigue
- 2006
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In: Archives of General Psychiatry. - : American Medical Association (AMA). - 0003-990X .- 1538-3636. ; 63:11, s. 1267-1272
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Journal article (peer-reviewed)abstract
- Elevated premorbid stress is a significant risk factor for chronic fatigue-like illness, the effect of which may be buffered by genetic influences. Emotional instability assessed 25 years earlier is associated with chronic fatigue through genetic mechanisms contributing to both personality style and expression of the disorder. These findings suggest plausible mechanisms for chronic fatiguing illness.
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