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Twin Research and Human Genetics : the... Dec 2019The Wisconsin Twin Project encompasses nearly 30 years of longitudinal research that spans infancy to early adulthood. The twin sample was recruited from statewide birth... (Review)
Review
The Wisconsin Twin Project encompasses nearly 30 years of longitudinal research that spans infancy to early adulthood. The twin sample was recruited from statewide birth records for birth cohorts 1989-2004. We summarize early recruitment, assessment, retention and recently completed twin neuroimaging studies. In addition to the focal twins, longitudinal data were also collected from two parents and nontwin siblings. Our adolescent and young adult neuroimaging sample (N = 600) completed several previous behavioral and environmental assessments, beginning shortly after birth. The extensive phenotyping is meant to support a range of empirical investigations with potentially differing theoretical perspectives.
Topics: Adolescent; Adult; Birth Certificates; Female; Humans; Longitudinal Studies; Male; Neuroimaging; Registries; Siblings; Temperament; Twin Studies as Topic; Twins, Dizygotic; Twins, Monozygotic; Wisconsin; Young Adult
PubMed: 31818344
DOI: 10.1017/thg.2019.108 -
JAMA Health Forum Jul 2021Wealthy adults tend to live longer than those with less wealth. However, a challenge in this area of research has been the reduction of potential confounding by factors...
IMPORTANCE
Wealthy adults tend to live longer than those with less wealth. However, a challenge in this area of research has been the reduction of potential confounding by factors associated with the early environment and heritable traits, which could simultaneously affect socioeconomic circumstances in adulthood and health across the life course.
OBJECTIVE
To identify the association between net worth at midlife and subsequent all-cause mortality in individuals as well as within siblings and twin pairs.
DESIGN SETTING AND PARTICIPANTS
This cohort study conducted a series of analyses using data from the Midlife in the United States (MIDUS) study, an ongoing national study of health and aging. The sample included adults (unrelated individuals, full siblings, and dizygotic and monozygotic twins) aged 20 to 75 years, who participated in wave 1 of the MIDUS study, which occurred from 1994 to 1996. The analyses were conducted between November 16, 2019, and May 18, 2021.
EXPOSURES
Self-reported net worth (total financial assets minus liabilities) at midlife (the middle years of life).
MAIN OUTCOMES AND MEASURES
All-cause mortality was tracked over nearly 24 years of follow-up, with a censor date of October 31, 2018. Survival models tested the association between net worth and all-cause mortality. Discordant sibling and twin analyses compared longevity within siblings and twin pairs who, given their shared early experiences and genetic backgrounds, were matched on these factors.
RESULTS
The full sample comprised 5414 participants, who had a mean (SD) age of 46.7 (12.7) years and included 2766 women (51.1%). Higher net worth was associated with lower mortality risk (hazard ratio [HR], 0.95; 95% CI, 0.94-0.97; < .001). Among siblings and twin pairs specifically (n = 2490), a similar within-family association was observed between higher net worth and lower mortality (HR, 0.94; 95% CI, 0.91-0.97; = .001), suggesting that the sibling or twin with more wealth tended to live longer than their co-sibling or co-twin with less wealth. When separate estimates were performed for the subsamples of siblings (HR, 0.94; 95% CI, 0.90-0.97; = .002), dizygotic twins (HR, 0.94; 95% CI, 0.86-1.02; = .19), and monozygotic twins (HR, 0.95; 95% CI, 0.87-1.04; = .34), the within-family estimates of the net worth-mortality association were similar, although the precision of estimates was reduced among twins.
CONCLUSIONS AND RELEVANCE
This cohort study found that wealth accumulation at midlife was associated with longevity in US adults. Discordant sibling analyses suggested that this association is unlikely to be simply an artifact of early experiences or heritable characteristics shared by families.
Topics: Adult; Aged; Cohort Studies; Female; Humans; Longevity; Longitudinal Studies; Male; Middle Aged; Social Class; Twins, Dizygotic; Twins, Monozygotic; United States; Young Adult
PubMed: 35977209
DOI: 10.1001/jamahealthforum.2021.1652 -
JAMA Psychiatry Jun 2024Exposure to adverse childhood experiences (ACEs) has consistently been associated with multiple negative mental health outcomes extending into adulthood. However, given...
IMPORTANCE
Exposure to adverse childhood experiences (ACEs) has consistently been associated with multiple negative mental health outcomes extending into adulthood. However, given that ACEs and psychiatric disorders cluster within families, it remains to be comprehensively assessed to what extent familial confounding contributes to associations between ACEs and clinically confirmed adult psychiatric disorders.
OBJECTIVE
To investigate whether associations between ACEs and adult mental health outcomes remain after adjusting for familial (genetic and environmental) confounding.
DESIGN, SETTING, AND PARTICIPANTS
This Swedish twin cohort study used a discordant twin pair design based on monozygotic (MZ) and dizygotic (DZ) twins. A total of 25 252 adult twins (aged 18-47 years) from the Swedish Twin Registry born between 1959 and 1998 were followed up from age 19 years until 2016, with a maximum follow-up time of 39 years. Data were analyzed from April 2022 to November 2023.
EXPOSURES
A total of 7 ACEs, including family violence, emotional abuse or neglect, physical neglect, physical abuse, sexual abuse, rape, and hate crime, were assessed with items from the Life Stressor Checklist-Revised in a web-based survey.
MAIN OUTCOMES AND MEASURES
Adult (ages >18 years) clinical diagnosis of psychiatric disorders (ie, depressive, anxiety, alcohol or drug misuse, or stress-related disorders) were obtained from the Swedish National Patient Register.
RESULTS
Of 25 252 twins included in the study (15 038 female [59.6%]; mean [SD] age at ACE assessment, 29.9 [8.7] years), 9751 individuals (38.6%) reported exposure to at least 1 ACE. A greater number of ACEs was associated with increased odds of any psychiatric disorder in the full cohort (odds ratio [OR] per additional ACE, 1.52; 95% CI, 1.48-1.57). The association remained but ORs per additional ACE were attenuated in DZ (1.29; 95% CI, 1.14-1.47) and MZ (1.20; 95% CI, 1.02-1.40) twin pairs. Individuals who were exposed to sexual abuse compared with those who were not exposed had increased odds of any clinically confirmed psychiatric disorder in all comparisons: full cohort (OR, 3.09; 95% CI, 2.68-3.56), DZ twin pairs (OR, 2.10; 95% CI, 1.33-3.32), and MZ twin pairs (1.80; 95% CI, 1.04-3.11).
CONCLUSIONS AND RELEVANCE
This study found that associations between ACEs and adult mental health outcomes remained after controlling for shared genetic and environmental factors, which was particularly evident after multiple ACEs or sexual abuse. These findings suggest that targeted interventions may be associated with reduced risks of future psychopathology.
Topics: Humans; Adult; Female; Male; Adverse Childhood Experiences; Sweden; Middle Aged; Young Adult; Adolescent; Mental Disorders; Registries; Cohort Studies; Twins, Monozygotic; Twins, Dizygotic; Mental Health
PubMed: 38446452
DOI: 10.1001/jamapsychiatry.2024.0039 -
Osteoarthritis and Cartilage Oct 2022To estimate the genetic contribution to doctor-diagnosed hand osteoarthritis (OA).
OBJECTIVE
To estimate the genetic contribution to doctor-diagnosed hand osteoarthritis (OA).
METHODS
Using data from the Swedish Twin Registry and National Patient Register, we conducted a 20-year population-based longitudinal cohort study including 59,970 twins aged 35 years or older. We studied inpatient and outpatient doctor-diagnosed hand OA using ICD-10 codes from 1997 until 2016, including both the distal/proximal interphalangeal (DIP/PIP) joints and/or the first carpometacarpal (CMC-1) joints. We calculated intra-pair correlation, estimated the heritability (i.e., the percentage variation in hand OA that can be explained by genetic factors) as well as a genetic risk.
RESULTS
Among 59,970 included persons, 936 had a hand OA diagnosis registered during the study period. The heritabilities of hand OA (any joint), CMC-1 OA and DIP/PIP OA were ∼87%, 86% and 48%, respectively, yet the two latter should be interpreted with care due to low numbers. Hand OA in any joint in both twins in a pair occurred more frequently in identical twins (54/554 = 9.7%, intra-pair correlation = 0.54, 95% CI = 0.44-0.63) than in fraternal twins (18/1,246 = 1.4%, intra-pair correlation = 0.10, 95% CI = -0.01-0.22). Identical twins who were diagnosed with hand OA in any joint had a far higher risk than fraternal twins with hand OA to also have their co-twin diagnosed with hand OA in any joint (Hazard Ratio = 6.98, 95% CI = 3.08-15.45).
CONCLUSION
The genetic contribution to hand OA is high and likely varying between 48% and 87%. Potential differential heritability by hand OA phenotypes should be further explored.
Topics: Carpometacarpal Joints; Hand; Humans; Longitudinal Studies; Osteoarthritis; Twins, Dizygotic; Twins, Monozygotic
PubMed: 35843480
DOI: 10.1016/j.joca.2022.06.011 -
The Journal of Molecular Diagnostics :... Sep 2023Twin pregnancy constitutes significant risks for maternal and fetal health, which is usually detected by ultrasound examination at early gestation. However, the...
Twin pregnancy constitutes significant risks for maternal and fetal health, which is usually detected by ultrasound examination at early gestation. However, the imaging-based approach may not accurately identify all twins confounded by practical or clinical variables. The analysis of fetal cell-free DNA in noninvasive prenatal screening assays can completement the ultrasound method for twin detection, which differentiates fraternal or identical twins based on their distinct genotypes. Here, a new noninvasive prenatal screening employing high-coverage next-generation sequencing for targeted nucleotide polymorphisms was developed for detection of zygosity and determination of fetal fraction in twin pregnancies. This method utilizes a binary analysis of both the number and allelic fraction of fetus-specific single-nucleotide polymorphisms to infer the zygosity. In 323 samples collected from 215 singleton, 90 dizygotic, and 18 monozygotic twin pregnancies, all 90 dizygotic twins were correctly detected, with a 100% sensitivity and a 100% specificity. In addition, this method can detect complex pregnancies, such as egg donors, contamination, and twins with complete hydatidiform mole. The fetus-specific fetal fraction change was monitored in nine dizygotic twin pregnancies, which demonstrated highly variable dynamics of fetal cell-free DNA turnover up to 7 weeks after twin reduction. Overall, this study provides a new noninvasive prenatal screening strategy for the accurate identification of twin zygosity and quantification of fetal fraction, which has important clinical implications for the management of twin pregnancies.
Topics: Female; Pregnancy; Humans; Pregnancy, Twin; Polymorphism, Single Nucleotide; Fetus; Alleles; Cell-Free Nucleic Acids
PubMed: 37599029
DOI: 10.1016/j.jmoldx.2023.06.003 -
Intelligence 2022Most research on individual differences in performance on tests of cognitive ability focuses on general cognitive ability (g), the highest level in the three-level...
Most research on individual differences in performance on tests of cognitive ability focuses on general cognitive ability (g), the highest level in the three-level Cattell-Horn-Carroll (CHC) hierarchical model of intelligence. About 50% of the variance of g is due to inherited DNA differences (heritability) which increases across development. Much less is known about the genetics of the middle level of the CHC model, which includes 16 broad factors such as fluid reasoning, processing speed, and quantitative knowledge. We provide a meta-analytic review of 747,567 monozygotic-dizygotic twin comparisons from 77 publications for these middle-level factors, which we refer to as specific cognitive abilities (SCA), even though these factors are not independent of g. Twin comparisons were available for 11 of the 16 CHC domains. The average heritability across all SCA is 56%, similar to that of g. However, there is substantial differential heritability across SCA and SCA do not show the developmental increase in heritability seen for g. We also investigated SCA independent of g (SCA.g). A surprising finding is that SCA.g remain substantially heritable (53% on average), even though 25% of the variance of SCA that covaries with g has been removed. Our review highlights the need for more research on SCA and especially on SCA.g. Despite limitations of SCA research, our review frames expectations for genomic research that will use polygenic scores to predict SCA and SCA.g. Genome-wide association studies of SCA.g are needed to create polygenic scores that can predict SCA profiles of cognitive abilities and disabilities independent of g.
PubMed: 37197611
DOI: 10.1016/j.intell.2022.101689 -
The Journal of Clinical Pediatric... Mar 2022The aim of this study is to investigate the relative contributions of genetic and environmental factors to variations in dental dimensions in a sample of Turkish twins,...
BACKGROUND
The aim of this study is to investigate the relative contributions of genetic and environmental factors to variations in dental dimensions in a sample of Turkish twins, and to estimate heritability using dental casts.
STUDY DESIGN
The study samples were selected from the twin children between 3-15 years old who referred for their first dental examination. Fifty nine monozygotic and one hundred and forty three dizygotic twin pairs were examined in the study. The alginate impression material used to create the plaster model of maxilla and mandible. Anterior arch width, posterior arch width, arch length and arch circumference were measured on models prepared from measurements taken for both maxilla and mandible with digital caliper. The similarities and differences of the measurements were compared between pairs of twins and zygocytes. Morever, the effects of bad oral habits, bruxism, a result of psychosocial factors on measurements were examined. Statistical analysis was performed using Paired T Test, Wilcoxon Test and Mann Whitney U test.
RESULTS
A total of 404 dental models of 118 (29.2%) monozygotic and 286 (70.8%) dizygotic twins were evaluated. There was no statistical difference between sibling pairs in both monozygotic and dizygotic twins. The measurement similarity between twin siblings differed according to zygosity in all measurements (p<0.05). It has been observed that the finger sucking and mouth breathing affect the dental arch measurements (p<0.05).
CONCLUSION
These results indicate that the differences in dental arch dimensions between monozygotic twin pairs are less than the difference between dizygotic twin pairs.
Topics: Adolescent; Child; Child, Preschool; Dental Arch; Humans; Mandible; Maxilla; Twins, Dizygotic; Twins, Monozygotic
PubMed: 35533222
DOI: 10.17796/1053-4625-46.2.12 -
Twin Research and Human Genetics : the... Dec 2019The Project Talent Twin and Sibling (PTTS) study includes 4481 multiples and their 522 nontwin siblings from 2233 families. The sample was drawn from Project Talent, a...
The Project Talent Twin and Sibling (PTTS) study includes 4481 multiples and their 522 nontwin siblings from 2233 families. The sample was drawn from Project Talent, a U.S. national longitudinal study of 377,000 individuals born 1942-1946, first assessed in 1960 and representative of U.S. students in secondary school (Grades 9-12). In addition to the twins and triplets, the 1960 dataset includes 84,000 siblings from 40,000 other families. This design is both genetically informative and unique in facilitating separation of the 'common' environment into three sources of variation: shared by all siblings within a family, specific to twin-pairs, and associated with school/community-level factors. We term this the GIFTS model for genetics, individual, family, twin, and school sources of variance. In our article published in a previous Twin Research and Human Genetics special issue, we described data collections conducted with the full Project Talent sample during 1960-1974, methods for the recent linking of siblings within families, identification of twins, and the design of a 54-year follow-up of the PTTS sample, when participants were 68-72 years old. In the current article, we summarize participation and data available from this 2014 collection, describe our method for assigning zygosity using survey responses and yearbook photographs, illustrate the GIFTS model applied to 1960 vocabulary scores from more than 80,000 adolescent twins, siblings and schoolmates and summarize the next wave of PTTS data collection being conducted as part of the larger Project Talent Aging Study.
Topics: Adolescent; Adult; Aged; Aptitude; Follow-Up Studies; Humans; Longitudinal Studies; Middle Aged; Siblings; Twins, Dizygotic; Twins, Monozygotic
PubMed: 32043952
DOI: 10.1017/thg.2019.117 -
Developmental Psychology Jul 2019Body dissatisfaction is a significant mental health symptom present in adolescent girls and boys. However, it is often either disregarded in adolescent boys or examined...
Body dissatisfaction is a significant mental health symptom present in adolescent girls and boys. However, it is often either disregarded in adolescent boys or examined using assessments that may not resonate with males. The present study addresses these issues, examining the manifestation, etiology, and correlates of 3 facets of body dissatisfaction in adolescent boys. Adolescent male twins aged 16- to 17-years-old from the Swedish Twin Study of Child and Adolescent Development were included along with a female comparison group: 915 monozygotic and 671 dizygotic same-sex twins. Body dissatisfaction was defined using measures of height dissatisfaction, muscle dissatisfaction, and the body dissatisfaction subscale of the Eating Disorder Inventory (EDI-BD). We examined the prevalence of body dissatisfaction, whether the facets of body dissatisfaction were phenotypically and etiologically distinct, and associations with specific externalizing and internalizing symptoms. For boys, muscle dissatisfaction scores were greater than height dissatisfaction scores. Results also indicated that height and muscle dissatisfaction were phenotypically and etiologically distinct from the EDI-BD. Unique associations were observed with externalizing and internalizing symptoms: muscle dissatisfaction with symptoms of bulimia nervosa and the EDI-BD with internalizing symptoms, body mass index, and drive for thinness. The facets of body dissatisfaction were also largely distinct in girls and unique between-sex associations with externalizing and internalizing symptoms emerged. Overall, male-oriented aspects of body dissatisfaction are distinct from female-oriented aspects of body dissatisfaction. To capture the full picture of male body dissatisfaction, multiple facets must be addressed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
Topics: Adolescent; Body Image; Feeding and Eating Disorders; Humans; Male; Muscle, Skeletal; Self Report; Sex Factors; Surveys and Questionnaires; Sweden; Twins
PubMed: 30985163
DOI: 10.1037/dev0000724 -
Hearing Research Dec 2020Our knowledge of which physiological mechanisms shape transient evoked otoacoustic emissions (TEOAEs) is incomplete, although thousands of TEOAEs are recorded each day...
Our knowledge of which physiological mechanisms shape transient evoked otoacoustic emissions (TEOAEs) is incomplete, although thousands of TEOAEs are recorded each day as part of universal newborn hearing-screening (UNHS). TEOAE heritability may explain some of the large TEOAE variability observed in neonates, and give insights into the TEOAE generators and modulators, and why TEOAEs are generally larger in females and right ears. The aim was to estimate TEOAE heritability and describe ear and sex effects in a consecutive subset of all twins that passed UNHS at the same occasion at two hospitals during a six-year period (more than 30 000 neonates screened in total). TEOAEs were studied and TEOAE level correlations compared in twin sets of same-sex (SS, 302 individual twins, 151 twin pairs) and opposite-sex (OS, 152 individual twins, 76 twin pairs). A mathematical model was used to estimate and compare monozygotic (MZ) and dizygotic (DZ) intra-twin pair TEOAE level correlations, based on the data from the SS and OS twin sets. For both SS and OS twin pairs TEOAE levels were significantly higher in right ears and females, compared to left ears and males, as previously demonstrated in young adult twins and large groups of neonates. Neonatal females in OS twin pairs did not demonstrate masculinized TEOAEs, as has been demonstrated for OAEs in young adult females in OS twin pairs. The within-twin pair TEOAE level correlations were higher for SS twin pairs than for OS twin pairs, whereas the within-pair correlation coefficients could not be distinguished from zero when twins were randomly paired. These results reflect heredity as a key factor in TEOAE level variability. Additionally, the estimated MZ within-twin pair TEOAE level correlations were higher than those for DZ twin pairs. The heritability estimates reached up to 100% TEOAE heritability, which is numerically larger than previous estimates of about 75% in young adult twins.
Topics: Female; Humans; Infant, Newborn; Male; Otoacoustic Emissions, Spontaneous; Young Adult
PubMed: 33212398
DOI: 10.1016/j.heares.2020.108108