| 51. |
- Humphreys, Keith, et al.
(författare)
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The Genetic Structure of the Swedish Population
- 2011
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:8, s. e22547-
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Tidskriftsartikel (refereegranskat)abstract
- Patterns of genetic diversity have previously been shown to mirror geography on a global scale and within continents and individual countries. Using genome-wide SNP data on 5174 Swedes with extensive geographical coverage, we analyzed the genetic structure of the Swedish population. We observed strong differences between the far northern counties and the remaining counties. The population of Dalarna county, in north middle Sweden, which borders southern Norway, also appears to differ markedly from other counties, possibly due to this county having more individuals with remote Finnish or Norwegian ancestry than other counties. An analysis of genetic differentiation (based on pairwise F(st)) indicated that the population of Sweden's southernmost counties are genetically closer to the HapMap CEU samples of Northern European ancestry than to the populations of Sweden's northernmost counties. In a comparison of extended homozygous segments, we detected a clear divide between southern and northern Sweden with small differences between the southern counties and considerably more segments in northern Sweden. Both the increased degree of homozygosity in the north and the large genetic differences between the south and the north may have arisen due to a small population in the north and the vast geographical distances between towns and villages in the north, in contrast to the more densely settled southern parts of Sweden. Our findings have implications for future genome-wide association studies (GWAS) with respect to the matching of cases and controls and the need for within-county matching. We have shown that genetic differences within a single country may be substantial, even when viewed on a European scale. Thus, population stratification needs to be accounted for, even within a country like Sweden, which is often perceived to be relatively homogenous and a favourable resource for genetic mapping, otherwise inferences based on genetic data may lead to false conclusions.
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| 52. |
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| 53. |
- Leu, Monica, et al.
(författare)
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NordicDB : a Nordic pool and portal for genome-wide control data
- 2010
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Ingår i: European Journal of Human Genetics. - : Springer Science and Business Media LLC. - 1018-4813 .- 1476-5438. ; 18:12, s. 1322-1326
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Tidskriftsartikel (refereegranskat)abstract
- A cost-efficient way to increase power in a genetic association study is to pool controls from different sources. The genotyping effort can then be directed to large case series. The Nordic Control database, NordicDB, has been set up as a unique resource in the Nordic area and the data are available for authorized users through the web portal (http://www.nordicdb.org). The current version of NordicDB pools together high-density genome-wide SNP information from similar to 5000 controls originating from Finnish, Swedish and Danish studies and shows country-specific allele frequencies for SNP markers. The genetic homogeneity of the samples was investigated using multidimensional scaling (MDS) analysis and pairwise allele frequency differences between the studies. The plot of the first two MDS components showed excellent resemblance to the geographical placement of the samples, with a clear NW-SE gradient. We advise researchers to assess the impact of population structure when incorporating NordicDB controls in association studies. This harmonized Nordic database presents a unique genome-wide resource for future genetic association studies in the Nordic countries. European Journal of Human Genetics (2010) 18, 1322-1326; doi: 10.1038/ejhg.2010.112; published online 28 July 2010
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| 54. |
- Magnusson, Patrik K. E., et al.
(författare)
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The Swedish Twin Registry : establishment of a biobank and other recent developments
- 2013
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Ingår i: Twin Research and Human Genetics. - Cambridge, United Kingdom : Cambridge University Press. - 1832-4274 .- 1839-2628. ; 16:1, s. 317-329
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Tidskriftsartikel (refereegranskat)abstract
- The Swedish Twin Registry (STR) today contains more than 194,000 twins and more than 75,000 pairs have zygosity determined by an intra-pair similarity algorithm, DNA, or by being of opposite sex. Of these, approximately 20,000, 25,000, and 30,000 pairs are monozygotic, same-sex dizygotic, and opposite-sex dizygotic pairs, respectively. Since its establishment in the late 1950s, the STR has been an important epidemiological resource for the study of genetic and environmental influences on a multitude of traits, behaviors, and diseases. Following large investments in the collection of biological specimens in the past 10 years we have now established a Swedish twin biobank with DNA from 45,000 twins and blood serum from 15,000 twins, which effectively has also transformed the registry into a powerful resource for molecular studies. We here describe the main projects within which the new collections of both biological samples as well as phenotypic measures have been collected. Coverage by year of birth, zygosity determination, ethnic heterogeneity, and influences of in vitro fertilization are also described.
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| 55. |
- Michaëlsson, Karl, et al.
(författare)
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Impact of hip fracture on mortality : a cohort study in hip fracture discordant identical twins
- 2014
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Ingår i: Journal of Bone and Mineral Research. - : Wiley-Blackwell. - 0884-0431 .- 1523-4681. ; 29:2, s. 424-431
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Tidskriftsartikel (refereegranskat)abstract
- Several studies have shown a long-lasting higher mortality after hip fracture but the reasons of the excess risk is not well understood. We aimed to determine whether there exists a higher mortality after hip fracture when controlling for genetic constitution, shared environment, comorbidity and lifestyle by use of a nation-wide cohort study in hip fracture discordant monozygotic twins. All 286 identical Swedish twin pairs discordant for hip fracture (1972-2010) were identified. Comorbidity and lifestyle information was retrieved by registers and questionnaire information. We used intrapair Cox regression to compute multivariable-adjusted hazard ratios (HRs) for death. During follow-up, 143 twins with a hip fracture died (50%) compared to 101 twins (35%) without a hip fracture. Through the first year after hip fracture, the rate of death increased four-fold in women (HR 3.71; 95% confidence interval (CI) 1.32-10.40) and seven-fold in men (HR 6.67; 95% CI 1.47-30.13). The increased rate in women only persisted during the first year after hip fracture (HR after 1 year 0.99; 95% CI 0.66-1.50), whereas the corresponding HR in men was 2.58 (95% CI 1.02-6.62). The higher risk in men after the hip fracture event was successively attenuated during follow-up. After 5 years, the hazard ratio in men with a hip fracture was 1.19 (95% CI 0.29-4.90). On average, the hip fracture contributed to 0.9 years of life lost in women (95% CI 0.06-1.7) and 2.7 years in men (95% CI 1.7-3.7). The potential years of life lost associated with the hip fracture was especially pronounced in older men (>75 years), with an average loss of 47% (95% CI 31-61) of the expected remaining lifetime. We conclude that both women and men display a higher mortality after hip fracture independent of genes, comorbidity and lifestyle.
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| 56. |
- Mosing, Miriam A, et al.
(författare)
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Genetic and environmental influences on the relationship between flow proneness, locus of control and behavioral inhibition
- 2012
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Ingår i: PLOS ONE. - : Public library of science. - 1932-6203. ; 7:11, s. e47958-
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Tidskriftsartikel (refereegranskat)abstract
- Flow is a psychological state of high but subjectively effortless attention that typically occurs during active performance of challenging tasks and is accompanied by a sense of automaticity, high control, low self-awareness, and enjoyment. Flow proneness is associated with traits and behaviors related to low neuroticism such as emotional stability, conscientiousness, active coping, self-esteem and life satisfaction. Little is known about the genetic architecture of flow proneness, behavioral inhibition and locus of control - traits also associated with neuroticism - and their interrelation. Here, we hypothesized that individuals low in behavioral inhibition and with an internal locus of control would be more likely to experience flow and explored the genetic and environmental architecture of the relationship between the three variables. Behavioral inhibition and locus of control was measured in a large population sample of 3,375 full twin pairs and 4,527 single twins, about 26% of whom also scored the flow proneness questionnaire. Findings revealed significant but relatively low correlations between the three traits and moderate heritability estimates of .41, .45, and .30 for flow proneness, behavioral inhibition, and locus of control, respectively, with some indication of non-additive genetic influences. For behavioral inhibition we found significant sex differences in heritability, with females showing a higher estimate including significant non-additive genetic influences, while in males the entire heritability was due to additive genetic variance. We also found a mainly genetically mediated relationship between the three traits, suggesting that individuals who are genetically predisposed to experience flow, show less behavioral inhibition (less anxious) and feel that they are in control of their own destiny (internal locus of control). We discuss that some of the genes underlying this relationship may include those influencing the function of dopaminergic neural systems.
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| 57. |
- Mosing, Miriam A., et al.
(författare)
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Genetic pleiotropy explains associations between musical auditory discrimination and intelligence
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:11
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Tidskriftsartikel (refereegranskat)abstract
- Musical aptitude is commonly measured using tasks that involve discrimination of different types of musical auditory stimuli. Performance on such different discrimination tasks correlates positively with each other and with intelligence. However, no study to date has explored these associations using a genetically informative sample to estimate underlying genetic and environmental influences. In the present study, a large sample of Swedish twins (N=10,500) was used to investigate the genetic architecture of the associations between intelligence and performance on three musical auditory discrimination tasks (rhythm, melody and pitch). Phenotypic correlations between the tasks ranged between 0.23 and 0.42 (Pearson r values). Genetic modelling showed that the covariation between the variables could be explained by shared genetic influences. Neither shared, nor non-shared environment had a significant effect on the associations. Good fit was obtained with a two-factor model where one underlying shared genetic factor explained all the covariation between the musical discrimination tasks and IQ, and a second genetic factor explained variance exclusively shared among the discrimination tasks. The results suggest that positive correlations among musical aptitudes result from both genes with broad effects on cognition, and genes with potentially more specific influences on auditory functions.
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| 58. |
- Mosing, Miriam A., et al.
(författare)
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Heritability of proneness for psychological flow experiences
- 2012
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Ingår i: Personality and Individual Differences. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0191-8869 .- 1873-3549. ; 53:5, s. 699-704
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Tidskriftsartikel (refereegranskat)abstract
- Flow is a subjective experience of high but effortless attention, loss of self-awareness, control, and enjoyment that can occur during active performance of challenging tasks. Proneness to experience flow is associated with personality, specifically with low neuroticism and high conscientiousness. We investigated genetic and non-genetic influences on flow proneness in 444 adult twin pairs. Data were collected using an on-line administration of the Swedish Flow Proneness Questionnaire, which includes separate scales for flow proneness in three major domains of life: work, maintenance, and leisure. We found moderate (.29-.35) heritabilities for the flow scales. Twin correlations as well as multivariate modeling suggested non-additive genetic influences. Genetic influences were almost entirely shared for the three flow scales and genetic correlations between the scales were very high (.81-.97), suggesting that the same genes influence flow proneness independently of domain. Non-shared environmental influences, in contrast, were largely specific to each flow scale. We conclude that an individual's general proneness to experience flow is influenced by the same genetic factors regardless of domain, and these may be associated with personality traits that are conducive to flow. In addition, specific environmental factors appear to be of importance for within-individual differences in flow proneness in different domains. (C) 2012 Elsevier Ltd. All rights reserved.
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| 59. |
- Mosing, Miriam A, et al.
(författare)
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Practice does not make perfect : no causal effect of music practice on music ability
- 2014
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Ingår i: Psychological Science. - : Sage Publications. - 0956-7976 .- 1467-9280. ; 25:9, s. 1795-1803
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Tidskriftsartikel (refereegranskat)abstract
- The relative importance of nature and nurture for various forms of expertise has been intensely debated. Music proficiency is viewed as a general model for expertise, and associations between deliberate practice and music proficiency have been interpreted as supporting the prevailing idea that long-term deliberate practice inevitably results in increased music ability. Here, we examined the associations (rs = .18–.36) between music practice and music ability (rhythm, melody, and pitch discrimination) in 10,500 Swedish twins. We found that music practice was substantially heritable (40%−70%). Associations between music practice and music ability were predominantly genetic, and, contrary to the causal hypothesis, nonshared environmental influences did not contribute. There was no difference in ability within monozygotic twin pairs differing in their amount of practice, so that when genetic predisposition was controlled for, more practice was no longer associated with better music skills. These findings suggest that music practice may not causally influence music ability and that genetic variation among individuals affects both ability and inclination to practice.
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| 60. |
- Nordström, Peter, et al.
(författare)
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High physical fitness in young adulthood reduces the risk of fractures later in life in men : a nationwide cohort study
- 2013
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Ingår i: Journal of Bone and Mineral Research. - : Wiley-Blackwell. - 0884-0431 .- 1523-4681. ; 28:5, s. 1061-1067
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Tidskriftsartikel (refereegranskat)abstract
- A few studies indicate that self reported physical activity is associated with the risk of fractures in middle-aged and elderly men. We investigated whether objectively measured physical fitness in young adulthood was associated with the risk of low-energy fractures later in life in men. Aerobic capacity and isometric muscle strength were measured in 435445 Swedish men that conscripted for military service from 1969-1978. Incident fractures were searched in national registers. During a median follow-up period of 35 years (range, 11-41 years), 8 030 subjects sustained at least one fracture, increasing the risk of death 1.8 times (95% CI = 1.6-2.0) during follow up. When comparing men in the lowest and highest decile of physical fitness, the risk of a fracture was 1.8 times higher (95% CI = 1.6-2.1) and that of hip fracture was 2.7 times higher (95% CI = 1.6-4.7). The risk of fracture was also 1.4-1.5 times higher when comparing the extreme deciles of muscle strength (p < 0.001 for all). In a subcohort of 1009 twin pairs, up to 22% of the variation in physical fitness and 27-39% of the variation in muscle strength was attributable to environmental factors unique to one twin, e.g. physical activity. In conclusion, low aerobic capacity and muscle strength in young adulthood are associated with an increased risk of low-energy fractures later in life, while a low-energy fracture is associated with an increased risk of death already in middle-aged men.
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