| 1. |
- 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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| 2. |
- Quinn, Patrick D., et al.
(författare)
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Childhood attention-deficit/hyperactivity disorder symptoms and the development of adolescent alcohol problems : A prospective, population-based study of Swedish twins
- 2016
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Ingår i: American Journal of Medical Genetics Part B. - Hoboken, USA : John Wiley & Sons. - 1552-4841 .- 1552-485X. ; 171:7, s. 958-970
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Tidskriftsartikel (refereegranskat)abstract
- Children with attention-deficit/hyperactivity disorder (ADHD) are at increased risk of problematic alcohol and other substance use in adolescence. This study used data from an ongoing, prospective, population-based twin study of Swedish children and adolescents to evaluate the extent to which the association between ADHD symptoms and alcohol problems reflects a unique source of genetic or environmental risk related to ADHD versus a broader predisposition to youth externalizing behavior. We used all available data from same-sex monozygotic (MZ) and dizygotic (DZ) twins on ADHD symptoms in childhood (age 9/12; N = 15,549) and alcohol problems in late adolescence (age 18; N = 2,564). Consistent with prior longitudinal studies, the phenotypic association between hyperactive/impulsive ADHD symptoms and alcohol problems was small in magnitude, whereas the association for inattentive symptoms was even weaker. Additive genetic influences explained 99.8% of the association between hyperactive/impulsive symptoms and alcohol problems. Furthermore, we found that the genetic risk specifically associated with hyperactive/impulsive symptoms was attenuated when estimated in the context of externalizing behavior liability during childhood, of which ADHD symptoms were specific expressions. In sensitivity analyses exploring hyperactivity in mid-adolescence, we found a similar pattern of genetic associations. These results are consistent with previous findings of genetically driven overlap in the etiology of ADHD and problematic alcohol use. At least some of this co-occurrence may result from a general predisposition to externalizing behaviors in youth. © 2015 Wiley Periodicals, Inc.
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| 3. |
- Törn, Peggy, et al.
(författare)
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Childhood neurodevelopmental problems and adolescent bully victimization : population-based, prospective twin study in Sweden
- 2015
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Ingår i: European Child and Adolescent Psychiatry. - New York, USA : Springer. - 1018-8827 .- 1435-165X. ; 24:9, s. 1049-1059
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Tidskriftsartikel (refereegranskat)abstract
- Bully victimization is a common problem among children with neurodevelopmental disorders, including attention deficit/hyperactivity disorder and autism spectrum disorder. Previous research was mostly cross-sectional and seldom accounted for co-morbid psychopathology, which makes it difficult to draw conclusions about causality and specificity of any association. Using a genetically informative prospective design, we investigated the association between various neurodevelopmental problems (NDPs) in childhood and bully victimization in adolescence, and the relative contributions of genetic and environmental factors to this association. We obtained parent-reports of NDPs at age 9/12 years and self-reported bully victimization at age 15 for 3,921 children participating in the The Child and Adolescent Twin Study in Sweden (CATSS). Structural equation modelling was used to control for NDP co-morbidity and bully victimization at baseline. Cholesky decomposition was used to analyse genetic and environmental contributions to observed associations. Because most of the NDPs were associated to later bully victimization, a common effect of all NDPs was summarized into a general NDP factor. Controlling for this general factor, only problems with social interaction and motor control uniquely predicted subsequent bully victimization in girls. General and unique associations were influenced by both genetic and unique environmental factors. NDPs in general and social interaction and motor problems in particular predicted later bully victimization. The longitudinal design and twin analyses indicated that these associations might be causal. Knowledge of these vulnerabilities may be important when designing risk assessment and prevention strategies.
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| 4. |
- Anckarsäter, Henrik, 1966, et al.
(författare)
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The Child and Adolescent Twin Study in Sweden (CATSS).
- 2011
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Ingår i: Twin Research and Human Genetics. - : Cambridge University Press (CUP). - 1832-4274 .- 1839-2628. ; 14:6, s. 495-508
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Tidskriftsartikel (refereegranskat)abstract
- The Child and Adolescent Twin Study in Sweden (CATSS) is an ongoing longitudinal twin study targeting all twins born in Sweden since July 1, 1992. Since 2004, parents of twins are interviewed regarding the children's somatic and mental health and social environment in connection with their 9th or 12th birthdays (CATSS-9/12). By January 2010, 8,610 parental interviews concerning 17,220 twins had been completed, with an overall response rate of 80%. At age 15 (CATSS-15) and 18 (CATSS-18), twins and parents complete questionnaires that, in addition to assessments of somatic and mental health, include measures of personality development and psychosocial adaptation. Twin pairs in CATSS-9/12 with one or both twins screening positive for autism spectrum disorders, attention deficit/hyperactivity disorder, tic disorders, developmental coordination disorder, learning disorders, oppositional defiant disorder, conduct disorder, obsessive-compulsive disorder, and/or eating problems have been followed with in-depth questionnaires on family, social environment and personality, and subsequently by clinical assessments at age 15 together with randomly selected population controls, including 195 clinically assessed twin pairs from the first 2 year cohorts (CATSS-15/DOGSS). This article describes the cohorts and study groups, data collection, and measures used. Prevalences, distributions, heritability estimates, ages at onset, and sex differences of mental health problems in the CATSS-9/12, that were analyzed and found to be overall comparable to those of other clinical and epidemiological studies. The CATSS study has the potential of answering important questions on the etiology of childhood mental health problems and their role in the development of later adjustment problems.
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| 5. |
- Donahue, Kelly L, et al.
(författare)
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Childhood Behavior Problems and Adolescent Sexual Risk Behavior: Familial Confounding in the Child and Adolescent Twin Study in Sweden (CATSS).
- 2013
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Ingår i: The Journal of adolescent health : official publication of the Society for Adolescent Medicine. - : Elsevier BV. - 1879-1972. ; 52:5
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Previous studies have found associations between childhood behavior problems and adolescent sexual risk behavior. Using a quasi-experimental approach, we examined the extent to which this association may be due to between-family differences (i.e., unmeasured familial confounds) not adequately explored in prior research. METHODS: We used data from a longitudinal, population-based cohort of young twins in Sweden (first assessment: age 9 or 12 years; second assessment: age 15; n = 2,388). We explored the nature of the association between symptom scores for attention deficit hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), and conduct disorder (CD) at age 9 or 12 and the likelihood of having had sexual intercourse and number of sexual partners by age 15. Two-level mixed-effects models were used to estimate the effect of symptom score on each outcome after controlling for potential unmeasured familial confounds. RESULTS: Higher ADHD, ODD, and CD scores were associated with significantly increased likelihood of sexual intercourse by age 15. Higher ADHD and ODD scores were also associated with increased number of sexual partners. After controlling for unmeasured familial confounds, however, behavior problems were no longer significantly associated with either outcome. CONCLUSION: The association between childhood behavior problems and sexual risk behaviors may be due to characteristics shared within families. Hence, prevention strategies aimed at reducing these behaviors might need to address broader risk factors that contribute to both behavior problems and a greater likelihood of sexual risk behavior.
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| 6. |
- Garcia, Danilo, 1973, et al.
(författare)
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The Genetic Structure of Cloninger's Psychobiological Model of Personality in Adolescence
- 2012
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Ingår i: Biological Psychiatry. - 0006-3223 .- 1873-2402.
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Konferensbidrag (refereegranskat)abstract
- Background: Cloninger’s psychobiological model is based on differences between procedural versus propositional learning, leading to the distinction between four temperament and three character dimensions. In contrast to Cloninger’s original theory, association studies and quantitative genetic studies have suggested at least equally (if not more) importance of genes and genetic effects behind characterdimensions as compared to temperament dimensions. We aimed to investigate the genetic structure of Cloninger’s model in a large population-based study group of adolescent twins to capture the developing personality. Methods: To understand which factors contributed to the seven TCI dimensions, we conducted univariate genetic analysis, using a model-fitting approach with structural equation-modeling techniques. Subjects: 831 monozygotic (MZ) or same-sex dizygotic (DZ) twin pairs aged 15 completed the Temperament and Character Inventory (TCI). Results: Three of the four temperament dimensions (Novelty Seeking, Harm Avoidance; Persistence) showed genetic contributions and unique environmental effects, supporting the original theoretical assumption and previous studies. As predicted by theory, all three character dimensions could be referred to genetic, common environmental, and unique environmental factors, with a considerably lower degree of genetic determinance (see Table 1). Conclusions: In contrast to previously published findings, the results presented here support the robustness of the original TCI structure.
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