| 1. |
- Silventoinen, K., et al.
(författare)
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The CODATwins Project : The current status and recent findings of COllaborative Project of Development of Anthropometrical Measures in Twins
- 2019
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Ingår i: Twin Research and Human Genetics. - : Cambridge University Press. - 1832-4274 .- 1839-2628. ; 22:6, s. 800-808
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Tidskriftsartikel (refereegranskat)abstract
- The COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) project is a large international collaborative effort to analyze individual-level phenotype data from twins in multiple cohorts from different environments. The main objective is to study factors that modify genetic and environmental variation of height, body mass index (BMI, kg/m2) and size at birth, and additionally to address other research questions such as long-term consequences of birth size. The project started in 2013 and is open to all twin projects in the world having height and weight measures on twins with information on zygosity. Thus far, 54 twin projects from 24 countries have provided individual-level data. The CODATwins database includes 489,981 twin individuals (228,635 complete twin pairs). Since many twin cohorts have collected longitudinal data, there is a total of 1,049,785 height and weight observations. For many cohorts, we also have information on birth weight and length, own smoking behavior and own or parental education. We found that the heritability estimates of height and BMI systematically changed from infancy to old age. Remarkably, only minor differences in the heritability estimates were found across cultural-geographic regions, measurement time and birth cohort for height and BMI. In addition to genetic epidemiological studies, we looked at associations of height and BMI with education, birth weight and smoking status. Within-family analyses examined differences within same-sex and opposite-sex dizygotic twins in birth size and later development. The CODATwins project demonstrates the feasibility and value of international collaboration to address gene-by-exposure interactions that require large sample sizes and address the effects of different exposures across time, geographical regions and socioeconomic status.
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| 2. |
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| 3. |
- Silventoinen, K., et al.
(författare)
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Differences in genetic and environmental variation in adult BMI by sex, age, time period, and region : An individual-based pooled analysis of 40 twin cohorts
- 2017
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Ingår i: American Journal of Clinical Nutrition. - : Oxford University Press. - 0002-9165 .- 1938-3207. ; 106:2, s. 457-466
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Tidskriftsartikel (refereegranskat)abstract
- Background: Genes and the environment contribute to variation in adult body mass index [BMI (in kg/m2)], but factors modifying these variance components are poorly understood.Objective: We analyzed genetic and environmental variation in BMI between men and women from young adulthood to old age from the 1940s to the 2000s and between cultural-geographic regions representing high (North America and Australia), moderate (Europe), and low (East Asia) prevalence of obesity.Design: We used genetic structural equation modeling to analyze BMI in twins ≥20 y of age from 40 cohorts representing 20 countries (140,379 complete twin pairs).Results: The heritability of BMI decreased from 0.77 (95% CI: 0.77, 0.78) and 0.75 (95% CI: 0.74, 0.75) in men and women 20-29 y of age to 0.57 (95% CI: 0.54, 0.60) and 0.59 (95% CI: 0.53, 0.65) in men 70-79 y of age and women 80 y of age, respectively. The relative influence of unique environmental factors correspondingly increased. Differences in the sets of genes affecting BMI in men and women increased from 20-29 to 60-69 y of age. Mean BMI and variances in BMI increased from the 1940s to the 2000s and were greatest in North America and Australia, followed by Europe and East Asia. However, heritability estimates were largely similar over measurement years and between regions. There was no evidence of environmental factors shared by co-twins affecting BMI.Conclusions: The heritability of BMI decreased and differences in the sets of genes affecting BMI in men and women increased from young adulthood to old age. The heritability of BMI was largely similar between cultural-geographic regions and measurement years, despite large differences in mean BMI and variances in BMI. Our results show a strong influence of genetic factors on BMI, especially in early adulthood, regardless of the obesity level in the population.
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| 4. |
- Jelenkovic, A., et al.
(författare)
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Genetic and environmental influences on adult human height across birth cohorts from 1886 to 1994
- 2016
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Ingår i: eLIFE. - Cambridge, United Kingdom : eLife Sciences Publications. - 2050-084X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Human height variation is determined by genetic and environmental factors, but it remains unclear whether their influences differ across birth-year cohorts. We conducted an individual-based pooled analysis of 40 twin cohorts including 143,390 complete twin pairs born 1886-1994. Although genetic variance showed a generally increasing trend across the birth-year cohorts, heritability estimates (0.69-0.84 in men and 0.53-0.78 in women) did not present any clear pattern of secular changes. Comparing geographic-cultural regions (Europe, North America and Australia, and East Asia), total height variance was greatest in North America and Australia and lowest in East Asia, but no clear pattern in the heritability estimates across the birth-year cohorts emerged. Our findings do not support the hypothesis that heritability of height is lower in populations with low living standards than in affluent populations, nor that heritability of height will increase within a population as living standards improve.
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| 5. |
- Jelenkovic, A, et al.
(författare)
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Genetic and environmental influences on height from infancy to early adulthood: An individual-based pooled analysis of 45 twin cohorts
- 2016
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Ingår i: Scientific reports. - London, United Kingdom : Springer Science and Business Media LLC. - 2045-2322. ; 6, s. 28496-
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Tidskriftsartikel (refereegranskat)abstract
- Height variation is known to be determined by both genetic and environmental factors, but a systematic description of how their influences differ by sex, age and global regions is lacking. We conducted an individual-based pooled analysis of 45 twin cohorts from 20 countries, including 180,520 paired measurements at ages 1–19 years. The proportion of height variation explained by shared environmental factors was greatest in early childhood, but these effects remained present until early adulthood. Accordingly, the relative genetic contribution increased with age and was greatest in adolescence (up to 0.83 in boys and 0.76 in girls). Comparing geographic-cultural regions (Europe, North-America and Australia and East-Asia), genetic variance was greatest in North-America and Australia and lowest in East-Asia, but the relative proportion of genetic variation was roughly similar across these regions. Our findings provide further insights into height variation during childhood and adolescence in populations representing different ethnicities and exposed to different environments.
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| 6. |
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| 7. |
- Jelenkovic, Aline, et al.
(författare)
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Zygosity Differences in Height and Body Mass Index of Twins From Infancy to Old Age : A Study of the CODATwins Project
- 2015
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Ingår i: Twin Research and Human Genetics. - : Cambridge University Press. - 1832-4274 .- 1839-2628. ; 18:5, s. 557-570
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Tidskriftsartikel (refereegranskat)abstract
- A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), and included 842,951 height and BMI measurements from twins aged 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Similarly, a greater mean BMI of up to 0.3 kg/m(2) in childhood and adolescence and up to 0.2 kg/m(2) in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast, the variance of BMI was significantly higher in DZ than in MZ twins, particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes.
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| 8. |
- Silventoinen, Karri, et al.
(författare)
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The CODATwins Project : The Cohort Description of Collaborative Project of Development of Anthropometrical Measures in Twins to Study Macro-Environmental Variation in Genetic and Environmental Effects on Anthropometric Traits
- 2015
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Ingår i: Twin Research and Human Genetics. - : Cambridge University Press. - 1832-4274 .- 1839-2628. ; 18:4
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Tidskriftsartikel (refereegranskat)abstract
- For over 100 years, the genetics of human anthropometric traits has attracted scientific interest. In particular, height and body mass index (BMI, calculated as kg/m2) have been under intensive genetic research. However, it is still largely unknown whether and how heritability estimates vary between human populations. Opportunities to address this question have increased recently because of the establishment of many new twin cohorts and the increasing accumulation of data in established twin cohorts. We started a new research project to analyze systematically (1) the variation of heritability estimates of height, BMI and their trajectories over the life course between birth cohorts, ethnicities and countries, and (2) to study the effects of birth-related factors, education and smoking on these anthropometric traits and whether these effects vary between twin cohorts. We identified 67 twin projects, including both monozygotic (MZ) and dizygotic (DZ) twins, using various sources. We asked for individual level data on height and weight including repeated measurements, birth related traits, background variables, education and smoking. By the end of 2014, 48 projects participated. Together, we have 893,458 height and weight measures (52% females) from 434,723 twin individuals, including 201,192 complete twin pairs (40% monozygotic, 40% same-sex dizygotic and 20% opposite-sex dizygotic) representing 22 countries. This project demonstrates that large-scale international twin studies are feasible and can promote the use of existing data for novel research purposes.
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| 9. |
- Luczak, S. E., et al.
(författare)
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Remember this : Age moderation of genetic and environmental contributions to verbal episodic memory from midlife through late adulthood
- 2023
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Ingår i: Intelligence. - : Elsevier. - 0160-2896 .- 1873-7935. ; 99
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Tidskriftsartikel (refereegranskat)abstract
- It is well documented that memory is heritable and that older adults tend to have poorer memory performance than younger adults. However, whether the magnitudes of genetic and environmental contributions to late-life verbal episodic memory ability differ from those at earlier ages remains unresolved. Twins from 12 studies participating in the Interplay of Genes and Environment in Multiple Studies (IGEMS) consortium constituted the analytic sample. Verbal episodic memory was assessed with immediate word list recall (N = 35,204 individuals; 21,792 twin pairs) and prose recall (N = 3805 individuals; 2028 twin pairs), with scores harmonized across studies. Average test performance was lower in successively older age groups for both measures. Twin models found significant age moderation for both measures, with total inter-individual variance increasing significantly with age, although it was not possible definitively to attribute the increase specifically to either genetic or environmental sources. Pooled results across all 12 studies were compared to results where we successively dropped each study (leave-one-out) to assure results were not due to an outlier. We conclude the models indicated an overall increase in variance for verbal episodic memory that was driven by a combination of increases in the genetic and nonshared environmental parameters that were not independently statistically significant. In contrast to reported results for other cognitive domains, differences in environmental exposures are comparatively important for verbal episodic memory, especially word list learning.
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| 10. |
- Piirtola, M., et al.
(författare)
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Association of current and former smoking with body mass index : A study of smoking discordant twin pairs from 21 twin cohorts
- 2018
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 13:7
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Tidskriftsartikel (refereegranskat)abstract
- Background Smokers tend to weigh less than never smokers, while successful quitting leads to an increase in body weight. Because smokers and non-smokers may differ in genetic and environmental family background, we analysed data from twin pairs in which the co-twins differed by their smoking behaviour to evaluate if the association between smoking and body mass index (BMI) remains after controlling for family background.Methods and findings The international CODATwins database includes information on smoking and BMI measured between 1960 and 2012 from 156,593 twin individuals 18–69 years of age. Individual-based data (230,378 measurements) and data of smoking discordant twin pairs (altogether 30,014 pairwise measurements, 36% from monozygotic [MZ] pairs) were analysed with linear fixed-effects regression models by 10-year periods. In MZ pairs, the smoking co-twin had, on average, 0.57 kg/m2 lower BMI in men (95% confidence interval (CI): 0.49, 0.70) and 0.65 kg/m2 lower BMI in women (95% CI: 0.52, 0.79) than the never smoking co-twin. Former smokers had 0.70 kg/m2 higher BMI among men (95% CI: 0.63, 0.78) and 0.62 kg/ m2 higher BMI among women (95% CI: 0.51, 0.73) than their currently smoking MZ co-twins. Little difference in BMI was observed when comparing former smoking co-twins with their never smoking MZ co-twins (0.13 kg/m2, 95% CI 0.04, 0.23 among men; -0.04 kg/m2, 95% CI -0.16, 0.09 among women). The associations were similar within dizygotic pairs and when analysing twins as individuals. The observed series of cross-sectional associations were independent of sex, age, and measurement decade.ConclusionsSmoking is associated with lower BMI and smoking cessation with higher BMI. However, the net effect of smoking and subsequent cessation on weight development appears to be minimal, i.e. never more than an average of 0.7 kg/m2
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| 11. |
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| 12. |
- Jelenkovic, A, et al.
(författare)
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Genetic and environmental influences on human height from infancy through adulthood at different levels of parental education
- 2020
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1, s. 7974-
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Tidskriftsartikel (refereegranskat)abstract
- Genetic factors explain a major proportion of human height variation, but differences in mean stature have also been found between socio-economic categories suggesting a possible effect of environment. By utilizing a classical twin design which allows decomposing the variation of height into genetic and environmental components, we tested the hypothesis that environmental variation in height is greater in offspring of lower educated parents. Twin data from 29 cohorts including 65,978 complete twin pairs with information on height at ages 1 to 69 years and on parental education were pooled allowing the analyses at different ages and in three geographic-cultural regions (Europe, North America and Australia, and East Asia). Parental education mostly showed a positive association with offspring height, with significant associations in mid-childhood and from adolescence onwards. In variance decomposition modeling, the genetic and environmental variance components of height did not show a consistent relation to parental education. A random-effects meta-regression analysis of the aggregate-level data showed a trend towards greater shared environmental variation of height in low parental education families. In conclusion, in our very large dataset from twin cohorts around the globe, these results provide only weak evidence for the study hypothesis.
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| 13. |
- Pedersen, N. L., et al.
(författare)
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IGEMS: The Consortium on Interplay of Genes and Environment Across Multiple Studies
- 2013
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Ingår i: Twin Research and Human Genetics. - : Cambridge University Press (CUP). - 1832-4274 .- 1839-2628. ; 16:1, s. 481-489
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Tidskriftsartikel (refereegranskat)abstract
- The Interplay of Genes and Environment across Multiple Studies (IGEMS) group is a consortium of eight longitudinal twin studies established to explore the nature of social context effects and gene-environment interplay in late-life functioning. The resulting analysis of the combined data from over 17,500 participants aged 25–102 at baseline (including nearly 2,600 monogygotic and 4,300 dizygotic twin pairs and over 1,700 family members) aims to understand why early life adversity, and social factors such as isolation and loneliness, are associated with diverse outcomes including mortality, physical functioning (health, functional ability), and psychological functioning (well-being, cognition), particularly in later life.
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| 14. |
- Silventoinen, Karri, et al.
(författare)
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Education in twins and their parents across birth cohorts over 100 years : an individual-level pooled analysis of 42 twin cohorts
- 2017
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Ingår i: Twin Research and Human Genetics. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 1832-4274 .- 1839-2628.
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Tidskriftsartikel (refereegranskat)abstract
- Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller in more recent birth cohorts for both males and females. Parental education was somewhat longer for fathers of DZ twins in cohorts born in 1990-1999 (0.16 years, 95% CI [0.08, 0.25]) and 2000 or later (0.11 years, 95% CI [0.00, 0.22]), compared with fathers of MZ twins. The results show that the years of both individual and parental education are largely similar in MZ and DZ twins. We suggest that the socio-economic differences between MZ and DZ twins are so small that inferences based upon genetic modeling of twin data are not affected.
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| 21. |
- 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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| 22. |
- Karlsson, Ida K., et al.
(författare)
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Apolipoprotein E ε4 genotype and the temporal relationship between depression and dementia
- 2015
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Ingår i: Neurobiology of Aging. - : Elsevier. - 0197-4580 .- 1558-1497. ; 36:4, s. 1751-1756
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Tidskriftsartikel (refereegranskat)abstract
- To investigate how apolipoprotein E (. APOE) affects the temporal relationship between depression and dementia, we conducted a nested case-control study with longitudinal depression and dementia evaluations from several population studies by using 804 dementia cases and 1600 matched controls, totaling 1519 unique individuals. Depression within 10 years of onset of dementia was strongly associated with dementia diagnosis regardless of APOE status (incidence rate ratio [IRR] 5.25, 95% confidence interval [95% CI] 3.32-8.31 for ε4 carriers, IRR 4.40, 95%CI 3.23-5.99 for noncarriers). However, we found a significant interaction between depression more than 10 years before the onset of dementia and APOE (. p= 0.01), with depression more distal to dementia being a risk factor only in ε4 carriers (IRR 3.39, 95% CI 1.69-6.78 for carriers, IRR 1.01, 95% CI 0.60-1.70 for noncarriers). Thus, depression with onset close in time to dementia onset is associated with disease irrespective of APOE genotype, whereas depression more distal to dementia onset is a risk factor only in ε4-carriers. This is the first study to show the interaction between APOE and depression to be dependent on timing of depression onset.
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| 23. |
- Lichtenstein, P, et al.
(författare)
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The Swedish Twin Registry in the third millennium: an update
- 2006
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Ingår i: Twin research and human genetics : the official journal of the International Society for Twin Studies. - : Cambridge University Press (CUP). - 1832-4274. ; 9:6, s. 875-882
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Tidskriftsartikel (refereegranskat)abstract
- The Swedish Twin Registry was first established in the late 1950s. Today it includes more than 170,000 twins — in principle all twins born in Sweden since 1886. In this article we describe some ongoing and recently completed projects based on the registry. In particular, we describe recent efforts to screen all twins born between 1959 and 1985, and young twin pairs when they turn 9 and 12 years of age. For these studies, we present initial frequencies of common conditions and exposures.
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| 24. |
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| 25. |
- Silventoinen, Karri, et al.
(författare)
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Genetic and environmental variation in educational attainment : an individual-based analysis of 28 twin cohorts
- 2020
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the heritability of educational attainment and how it differed between birth cohorts and cultural–geographic regions. A classical twin design was applied to pooled data from 28 cohorts representing 16 countries and including 193,518 twins with information on educational attainment at 25 years of age or older. Genetic factors explained the major part of individual differences in educational attainment (heritability: a2 = 0.43; 0.41–0.44), but also environmental variation shared by co-twins was substantial (c2 = 0.31; 0.30–0.33). The proportions of educational variation explained by genetic and shared environmental factors did not differ between Europe, North America and Australia, and East Asia. When restricted to twins 30 years or older to confirm finalized education, the heritability was higher in the older cohorts born in 1900–1949 (a2 = 0.44; 0.41–0.46) than in the later cohorts born in 1950–1989 (a2 = 0.38; 0.36–0.40), with a corresponding lower influence of common environmental factors (c2 = 0.31; 0.29–0.33 and c2 = 0.34; 0.32–0.36, respectively). In conclusion, both genetic and environmental factors shared by co-twins have an important influence on individual differences in educational attainment. The effect of genetic factors on educational attainment has decreased from the cohorts born before to those born after the 1950s.
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| 26. |
- Andel, R, et al.
(författare)
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Complexity of primary lifetime occupation and cognition in advanced old age
- 2007
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Ingår i: Journal of aging and health. - : SAGE Publications. - 0898-2643 .- 1552-6887. ; 19:3, s. 397-415
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The authors explored the association between complexity of primary lifetime occupation and cognition in older adulthood. Method: The study included 386 participants from the Swedish Panel Study of Living Conditions of the Oldest Old, a nationally representative sample aged 77 years or older. The authors examined complexity of work with data, people, and things in relation to cognitive functioning, measured with a shortened version of Mini-Mental State Examination (MMSE) and cognitive impairment based on MMSE score cutoff. Results: Complexity of work with data and people were associated with better MMSE scores, controlling for age, sex, childhood socioeconomic status, and education. The association between complexity of work with data and MMSE remained statistically significant when adult occupational status was substituted for education as a covariate. Discussion: Complexity of primary lifetime occupation may be reflected in cognitive functioning even in advanced old age. This effect may be independent of education or occupational status.
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| 27. |
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| 28. |
- Andel, R, et al.
(författare)
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Physical exercise at midlife and risk of dementia three decades later: a population-based study of Swedish twins.
- 2008
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Ingår i: J Gerontol A Biol Sci Med Sci. ; 63:1, s. 62-6
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: With the number of people with dementia increasing, identifying potential protective factors has become more important. We explored the association between physical exercise at midlife and subsequent risk of dementia among members of the HARMONY study. METHODS: Measures of exercise were obtained by the Swedish Twin Registry an average of 31 years prior to dementia assessment. Dementia was diagnosed using a two-stage procedure--screening for cognitive impairment followed by full clinical evaluation. We used two study designs: case-control analyses included 264 cases with dementia (176 had Alzheimer's disease) and 2870 controls; co-twin control analyses included 90 twin pairs discordant for dementia. RESULTS: In case-control analyses, controlling for age, sex, education, diet (eating fruits and vegetables), smoking, drinking alcohol, body mass index, and angina, light exercise such as gardening or walking and regular exercise involving sports were associated with reduced odds of dementia compared to hardly any exercise (odds ratio [OR] = 0.63, 95% confidence interval [CI], 0.43-0.91 for light exercise; OR = 0.34, 95% CI, 0.16-0.72 for regular exercise). Findings were similar for Alzheimer's disease alone. In co-twin control analyses, controlling for education, the association between higher levels of exercise and lower odds of dementia approached significance (OR = 0.50, 95% CI, 0.23-1.06; p =.072). CONCLUSIONS: Exercise at midlife may reduce the odds of dementia in older adulthood, suggesting that exercise interventions should be explored as a potential strategy for delaying disease onset
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| 35. |
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| 36. |
- Feychting, M, et al.
(författare)
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Dementia and occupational exposure to magnetic fields
- 1998
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Ingår i: Scandinavian journal of work, environment & health. - : Scandinavian Journal of Work, Environment and Health. - 0355-3140 .- 1795-990X. ; 24:1, s. 46-53
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Tidskriftsartikel (refereegranskat)
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| 37. |
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| 38. |
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| 39. |
- Gatz, M, et al.
(författare)
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Accounting for the relationship between low education and dementia: a twin study.
- 2007
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Ingår i: Physiol Behav. ; , s. 232-237
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Tidskriftsartikel (refereegranskat)abstract
- We evaluated whether the association between low education and greater risk of dementia is explained by genetic influences, using three different types of analyses. The HARMONY study (Swedish for "health" (Hälsa), "genes" (ARv), "environment" (Miljö), "and" (Och), and "new" (NY)) includes members of the Swedish Twin Registry who were aged 65 and older and alive in 1998, and who were screened and clinically assessed for dementia. There were 394 cases with dementia and 7786 unrelated controls. Analyses included co-twin control, tests for association between education and a measured genotype, and bivariate twin modeling. Low education was a significant risk factor for dementia both in case-control analyses (odds ratio=1.77, 95% confidence interval 1.38 to 2.28) and co-twin control analyses with monozygotic twin pairs (odds ratio=3.17, 95% confidence interval 1.26 to 7.93). Apolipoprotein E genotype was not associated with education and did not account for the relationship between education and dementia. Bivariate twin modeling showed that the association between education and dementia was not mediated by genetic influences in common between education and dementia. The association was mediated by shared environmental influences that were related to both dementia and to education. Low education is confirmed as a risk factor for dementia. Findings from three different analytic approaches showed that genetic influences did not explain this association.
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| 48. |
- Johansson, Boo, et al.
(författare)
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Complexity of work and risk of Alzheimer's disease: a population-based study of Swedish twins.
- 2005
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Ingår i: J Gerontology: Psychological Science. ; , s. 251-8
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Tidskriftsartikel (refereegranskat)abstract
- We examined the association between risk of dementia or Alzheimer's disease (AD) and occupation by using measures of complexity of work with data, people, and things. The study included 10,079 members of the population-based Swedish Twin Registry who were participants in the HARMONY study. We diagnosed dementia by means of a two-stage procedure--cognitive impairment screening fol-lowed by full clinical evaluation. We analyzed data with case-control and cotwin control designs. The cotwin control design provides control over genetic and fa-milial factors. In the case-control study, controlling for age, gender, and level of education, we found that more complex work with people was associated with re-duced risk of AD. Greater complexity of work with people and data was protective in twin pairs discordant for AD. Findings suggest that greater complexity of work, and particularly complex work with people, may reduce the risk of AD.
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| 50. |
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