| 1. |
- Evengård, Birgitta, 1952-, et al.
(författare)
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The epidemiology of chronic fatigue in the Swedish Twin Registry
- 2005
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Ingår i: Psychological Medicine. - 0033-2917 .- 1469-8978. ; 35:9, s. 1317-1326
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Tidskriftsartikel (refereegranskat)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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| 2. |
- Jansson, M, et al.
(författare)
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Gender differences in heritability of depressive symptoms in the elderly
- 2004
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Ingår i: PSYCHOLOGICAL MEDICINE. - 0033-2917 .- 1469-8978. ; 34:3, s. 471-479
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The present study aimed to investigate the relative importance of genetic and environmental influences on depressive symptoms in the elderly. METHOD: Depressive symptoms were assessed through the Center for Epidemiological Studies-Depression (CES-D) scale. The CES-D scale was administered to 959 twin pairs (123 female MZs, 90 male MZs, 207 same-sex female DZs, 109 same-sex male DZs and 430 opposite-sex DZs) aged 50 years or older (mean age 72 years). A dichotomous depressed state variable was constructed based on CES-D cut-offs and self-reported use of antidepressant medication. Structural equation models were fitted to the data to dissect genetic and environmental variance components. RESULTS: The sex-specific heritability estimates for depressive symptoms were 14% for males and 29% for females and 23% when constrained to be equal for men and women. The prevalence of clinically significant depressive symptoms was 16% for men and 24% for women. Heritability estimates for the dichotomous depressed state measure were 7% for males and 49% for females in the full model and 33% when constrained to be equal. CONCLUSION: Our results suggest that depressive symptoms in the elderly are moderately heritable, with a higher heritability for women than men, although differences in heritability estimates were not statistically significant.
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| 3. |
- Kato, K, et al.
(författare)
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A population-based twin study of functional somatic syndromes
- 2009
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Ingår i: Psychological Medicine. - : Cambridge University Press. - 0033-2917 .- 1469-8978. ; 39:3, s. 497-505
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Tidskriftsartikel (refereegranskat)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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| 4. |
- Sullivan, Patrick F, et al.
(författare)
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Chronic fatigue in a population sample : definitions and heterogeneity
- 2005
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Ingår i: Psychological Medicine. - 0033-2917 .- 1469-8978. ; 35:9, s. 1337-1348
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Tidskriftsartikel (refereegranskat)abstract
- Our data are consistent with the 'existence' of CFS-like illness although the dominant nosological approach captures population-level variation poorly. We suggest that studying a more parsimonious case definition - impairing chronic fatigue not due to a known cause - would represent a way forward.
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| 5. |
- Sullivan, Patrick F, et al.
(författare)
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Twin analyses of chronic fatigue in a Swedish national sample
- 2005
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Ingår i: Psychological Medicine. - 0033-2917 .- 1469-8978. ; 35:9, s. 1327-1336
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Tidskriftsartikel (refereegranskat)abstract
- Current fatiguing illness appears to be a complex trait resulting from both environmental and genetic sources of variation without pronounced differences by gender.
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