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Sleep Health Oct 2021The causal nature of the sleep-obesity association is unclear. To control for potential confounding by genes and shared environment, we studied monozygotic twin pairs...
OBJECTIVES
The causal nature of the sleep-obesity association is unclear. To control for potential confounding by genes and shared environment, we studied monozygotic twin pairs discordant for body mass index (BMI). First, we investigated sleep in relation to BMI. Second, we examined associations of objective and subjective sleep duration and sleep debt (objective or subjective sleep duration minus subjective sleep need) with eating behaviors and physical activity (PA).
DESIGN
Cross-sectional study.
SETTING
Finnish twins in everyday life circumstances.
PARTICIPANTS
Seventy-four healthy young adult monozygotic twin pairs, of whom 36 were BMI-discordant (∆BMI ≥ 3 kg/m).
MEASUREMENTS
Clinical measurements estimated BMI and body composition. Sleep, eating, and PA behaviors were measured by self-report and actigraphy.
RESULTS
Compared to co-twins with lower BMI, co-twins with higher BMI reported shorter sleep (P = .043), more snoring (P = .0093), and greater tiredness (P = .0013) and trended toward eveningness (P = .036). Actigraphy-measured sleep duration correlated highly within BMI-discordant twin pairs (r = 0.63, P = .004). Subjective sleep debt was consistently positively associated with disinhibited eating and binge eating, but not with BMI. Subjective and objective sleep debt had negative correlations with moderate-to-vigorous PA.
CONCLUSIONS
Twins with higher BMI showed less favorable sleep characteristics than their co-twins with lower BMI. Subjective sleep debt is a potential target for intervention to reduce eating and PA behaviors that promote weight gain. Experimental studies could elucidate mechanisms underlying tiredness in individuals with higher BMI and investigate causal relationships between sleep debt, BMI, and lifestyle.
Topics: Body Mass Index; Cross-Sectional Studies; Humans; Life Style; Sleep; Twins, Monozygotic; Young Adult
PubMed: 34193396
DOI: 10.1016/j.sleh.2021.04.002 -
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 Clinical Endocrinology... Dec 2022Clarification of the association among phenotypes, genetic, and environmental factors with clinical laboratory traits can reveal the cause of diseases and assist in...
CONTEXT
Clarification of the association among phenotypes, genetic, and environmental factors with clinical laboratory traits can reveal the cause of diseases and assist in developing methods for the prediction and prevention of diseases. It is difficult to investigate the environmental effect on phenotypes using individual samples because their genetic and environmental factors differ, but we can easily investigate the influence of environmental factors using monozygotic (MZ) twins because they have the same genetic factors.
OBJECTIVE
We aimed to examine the methylation level of CpG sites as an environmental factor affecting adiponectin levels on the basis of the same genetic background using MZ twins and to identify the epigenetic factors related to adiponectin levels and the genetic factors associated with sensitivity to acquired changes in adiponectin.
METHODS
Using 2 groups built from each twin of 232 MZ twin pairs, we performed a replicated epigenome-wide association study to clarify the epigenetic factors affecting adiponectin levels adjusted by genetic risk score. Moreover, we divided twin pairs into concordant and discordant for adiponectin levels. We conducted a genome-wide association study to identify a genetic background specific for discordance.
RESULTS
Methylation levels at 38 CpG sites were reproducibly associated with adjusted adiponectin levels, and some of these CpG sites were in genes related to adiponectin, including CDH13. Some genes related to adiponectin or insulin resistance were found to be genetic factors specific for discordance.
CONCLUSION
We clarified specific epigenetic factors affecting adiponectin levels and genetic factors associated with sensitivity to acquired changes in adiponectin.
Topics: Humans; Adiponectin; DNA Methylation; Genome-Wide Association Study; Twins, Monozygotic; Epigenesis, Genetic
PubMed: 36082629
DOI: 10.1210/clinem/dgac532 -
Acta Odontologica Scandinavica Apr 2022To resolve how the preferred chewing side (PCS) affects facial asymmetry in twins, whether there are differences between monozygotic (MZ) and dizygotic (DZ) twins, and...
OBJECTIVE
To resolve how the preferred chewing side (PCS) affects facial asymmetry in twins, whether there are differences between monozygotic (MZ) and dizygotic (DZ) twins, and whether the twins with PCS have more asymmetric faces compared to symmetrically chewing twins.
MATERIAL AND METHODS
The study included 106 Lithuanian twin pairs of the same sex, 59 MZ and 47 DZ pairs. The data were analysed from facial 3D images and manually added landmarks. 3D images were analysed by Rapidform2006 software and statistical analyses were done by using the R software environment version 4.1.0.
RESULTS
The contralateral effect of PCS and larger chin side was dominant among right and non-right side chewing twins. Being female increased the whole face symmetry.
CONCLUSION
The volume of the chin becomes larger on the side opposite to the twins' habitual chewing side. As the results are quite similar in both twin types, functional factors are more prominent than heredity.
Topics: Face; Facial Asymmetry; Female; Humans; Mastication; Twins, Dizygotic; Twins, Monozygotic
PubMed: 34619067
DOI: 10.1080/00016357.2021.1985166 -
BMC Psychiatry Jun 2023The causes of obsessive-compulsive disorder (OCD) remain unknown. Gene-searching efforts are well underway, but the identification of environmental risk factors is at...
BACKGROUND
The causes of obsessive-compulsive disorder (OCD) remain unknown. Gene-searching efforts are well underway, but the identification of environmental risk factors is at least as important and should be a priority because some of them may be amenable to prevention or early intervention strategies. Genetically informative studies, particularly those employing the discordant monozygotic (MZ) twin design, are ideally suited to study environmental risk factors. This protocol paper describes the study rationale, aims, and methods of OCDTWIN, an open cohort of MZ twin pairs who are discordant for the diagnosis of OCD.
METHODS
OCDTWIN has two broad aims. In Aim 1, we are recruiting MZ twin pairs from across Sweden, conducting thorough clinical assessments, and building a biobank of biological specimens, including blood, saliva, urine, stool, hair, nails, and multimodal brain imaging. A wealth of early life exposures (e.g., perinatal variables, health-related information, psychosocial stressors) are available through linkage with the nationwide registers and the Swedish Twin Registry. Blood spots stored in the Swedish phenylketonuria (PKU) biobank will be available to extract DNA, proteins, and metabolites, providing an invaluable source of biomaterial taken at birth. In Aim 2, we will perform within-pair comparisons of discordant MZ twins, which will allow us to isolate unique environmental risk factors that are in the causal pathway to OCD, while strictly controlling for genetic and early shared environmental influences. To date (May 2023), 43 pairs of twins (21 discordant for OCD) have been recruited.
DISCUSSION
OCDTWIN hopes to generate unique insights into environmental risk factors that are in the causal pathway to OCD, some of which have the potential of being actionable targets.
Topics: Female; Humans; Infant, Newborn; Pregnancy; Brain; Diseases in Twins; Obsessive-Compulsive Disorder; Risk Factors; Twins, Monozygotic; Twin Studies as Topic
PubMed: 37328750
DOI: 10.1186/s12888-023-04897-4 -
Twin Research and Human Genetics : the... Apr 2024Between 2006 and 2021, the Hungarian Twin Registry (HTR) operated a volunteer twin registry of all age groups (50% monozygotic [MZ], 50% dizygotic [DZ], 70% female,...
Between 2006 and 2021, the Hungarian Twin Registry (HTR) operated a volunteer twin registry of all age groups (50% monozygotic [MZ], 50% dizygotic [DZ], 70% female, average age 34 ± 22 years), including 1044 twin pairs, 24 triplets and one quadruplet set. In 2021, the HTR transformed from a volunteer registry into a population-based one, and it was established in the Medical Imaging Centre of Semmelweis University in Budapest. Semmelweis University's innovation fund supported the development of information technology, a phone bank and voicemail infrastructure, administrative materials, and a new website was established where twins and their relatives (parent, foster parent or caregiver) can register. The HTR's biobank was also established: 157,751 individuals with a likely twin-sibling living in Hungary (77,042 twins, 1194 triplets, 20 quadruplets, and one quintuplet) were contacted between February and March of 2021 via sealed letters. Until November 20, 2022, 12,001 twin individuals and their parents or guardians (6724 adult twins, 3009 parents/guardians and 5277 minor twins) registered, mostly online. Based on simple self-reports, 37.6% of the registered adults were MZ twins and 56.8% were DZ; 1.12% were triplets and 4.5% were unidentified. Of the registered children, 22.3% were MZ, 72.7% were DZ, 1.93% were triplets, and 3.05% were unidentified. Of the registered twins, 59.9% were female (including both the adult and minor twins). The registration questionnaire consists of eight parts, including socio-demographic and anthropometric data, smoking habits and medical questions (diseases, operations, therapies). Hungary's twin registry has become the sole and largest population-based twin registry in Central Eastern Europe. This new resource will facilitate performing world-class modern genetic research.
Topics: Humans; Registries; Hungary; Female; Male; Adult; Twins, Dizygotic; Twins, Monozygotic; Child; Middle Aged; Adolescent; Child, Preschool; Aged; Diseases in Twins; Young Adult; Infant
PubMed: 38745426
DOI: 10.1017/thg.2024.15 -
Twin Research and Human Genetics : the... Dec 2019The aim of the Avera Twin Register (ATR) is to establish a prospective longitudinal repository of twins, multiples, siblings and family members' biological samples to... (Review)
Review
The aim of the Avera Twin Register (ATR) is to establish a prospective longitudinal repository of twins, multiples, siblings and family members' biological samples to study environmental and genetic influences on health and disease. Also, it is our intention to contribute to international genome-wide association study (GWAS) twin consortia when appropriate sample size is achieved within the ATR. The ATR is young compared with existing registers and continues to collect a longitudinal repository of biological specimens, survey data and health information. Data and biological specimens were originally collected via face-to-face appointments or the postal department and consisted of paper-informed consents and questionnaires. Enrollment of the ATR began on May 18, 2016 and is located in Sioux Falls, South Dakota, a rural and frontier area in the Central United States with a regional population of approximately 880,000. The original target area for the ATR was South Dakota and the four surrounding states: Minnesota, Iowa, North Dakota and Nebraska. The ATR has found a need to expand that area based on twin and multiple siblings who live in various areas surrounding these states. A description of the state of the ATR today and its transition to online data collection and informed consent will be presented. The ATR collects longitudinal data on lifestyle, including diet and activity levels, aging, plus complex traits and diseases. All twins and multiples participating in the ATR are genotyped on the Illumina Global Screening Array and receive zygosity results.
Topics: Human Genetics; Humans; Registries; Twin Studies as Topic; Twins, Dizygotic; Twins, Monozygotic
PubMed: 31608846
DOI: 10.1017/thg.2019.73 -
Twin Research and Human Genetics : the... Jun 2022In this study, we analyzed the estimated frequency of monozygotic (MZ) and dizygotic (DZ) spontaneous twins in Lombardy during the period 2007-2017. This is a...
In this study, we analyzed the estimated frequency of monozygotic (MZ) and dizygotic (DZ) spontaneous twins in Lombardy during the period 2007-2017. This is a population-based study using the regional healthcare utilization databases of the Lombardy Region. The total number of spontaneous twin deliveries, in separate strata of like and unlike sex, was obtained. Moreover, estimates of DZ and MZ twin births were calculated using Weinberg's method. The standardized rates (SRs), adjusted for maternal age, of DZ and MZ twin births were computed according to calendar period. The twinning rates were calculated among strata of parity and maternal age. Finally, DZ:MZ ratio was calculated. Among the 734,278 spontaneous deliveries, 9176 (12.5 out of 1000 births) couples of twins were identified. In the three periods considered (i.e. 2007-2010, 2011-2014 and 2015-2017), no trend in the SRs of MZ twins was observed, respectively 0.41 (95% CI [0.40, 0.43]), 0.43 (95% CI [0.42, 0.45]) and 0.43 (95% CI[0.42, 0.45]). Differently, a slightly decreasing trend was observed in DZ twins SRs, respectively 0.87 (95% CI [0.84, 0.89]), 0.81 (95% CI [0.79, 0.83]), and 0.78 (95% CI [0.76, 0.80]). As concerns parity and maternal age, the rate of DZ twin births was consistently higher in nulliparae women aged 35 years or more. In our cohort, despite the increase of maternal age, a decline of spontaneous twin births emerged, especially due to the downward trend of DZ twins.
Topics: Adult; Female; Humans; Maternal Age; Pregnancy; Pregnancy, Twin; Twinning, Dizygotic; Twins, Dizygotic; Twins, Monozygotic
PubMed: 35765814
DOI: 10.1017/thg.2022.19 -
Twin Research and Human Genetics : the... Feb 2020In 1984, Hrubec and Robinette published what was arguably the first review of the role of twins in medical research. The authors acknowledged a growing distinction... (Review)
Review
In 1984, Hrubec and Robinette published what was arguably the first review of the role of twins in medical research. The authors acknowledged a growing distinction between two categories of twin studies: those aimed at assessing genetic contributions to disease and those aimed at assessing environmental contributions while controlling for genetic variation. They concluded with a brief section on recently founded twin registries that had begun to provide unprecedented access to twins for medical research. Here we offer an overview of the twin research that, in our estimation, best represents the field has progress since 1984. We start by summarizing what we know about twinning. We then focus on the value of twin study designs to differentiate between genetic and environmental influences on health and on emerging applications of twins in multiple areas of medical research. We finish by describing how twin registries and networks are accelerating twin research worldwide.
Topics: Biomedical Research; Diseases in Twins; Epigenesis, Genetic; Female; Gene-Environment Interaction; Humans; Male; Microbiota; Registries; Stem Cells; Twin Studies as Topic; Twins, Dizygotic; Twins, Monozygotic
PubMed: 31983355
DOI: 10.1017/thg.2020.4 -
Reproductive Biology and Endocrinology... Jun 2023Monozygotic twins (MZTs) are associated with high risks of maternal and fetal complications. Even with the widely used elective single embryo transfer (SET), the risk of...
BACKGROUND
Monozygotic twins (MZTs) are associated with high risks of maternal and fetal complications. Even with the widely used elective single embryo transfer (SET), the risk of MZTs following assisted reproductive technology (ART) treatments remains. However, most studies of MZTs focused on the relevant etiology, with few studies describing pregnancy and neonatal outcomes.
METHODS
This retrospective cohort study included 19,081 SET cycles resulting from in-vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), preimplantation genetic testing (PGT) and testicular sperm aspiration (TESA) performed between January 2010 and July 2020 in a single university-based center. A total of 187 MZTs were included in this investigation. The main outcome measures were the incidence, pregnancy and neonatal outcomes of MZTs. Multivariate logistic regression analysis was performed to figure out the risk factors for pregnancy loss.
RESULTS
The overall rate of MZTs from ART treatment in SET cycles was 0.98%. No significant difference was found in the incidence of MZTs among the four groups (p = 0.259). The live birth rate of MZTs in the ICSI group (88.5%) was significantly more favorable than in the IVF, PGT and TESA groups (60.5%, 77.2% and 80%, respectively). IVF resulted in a significantly increased risk of pregnancy loss (39.4%) and early miscarriage (29.5%) in MZT pregnancies compared to ICSI (11.4%, 8.5%), PGT (22.7%, 16.6%) and TESA (20%, 13.3%). The total rate of twin-to-twin transfusion syndrome (TTTS) in MZTs was 2.7% (5/187); however, the TESA group had the highest rate at 20% and was significantly higher than the PGT group (p = 0.005). The four ART groups had no significant effect on the occurrence of congenital abnormalities or other neonatal outcomes in newborns from MZT pregnancies. Multivariate logistic regression analysis revealed that infertility duration, cause of infertility, the total dose of Gn used, history of miscarriages, and the number of miscarriages were not related to the risk of pregnancy loss (p > 0.05).
CONCLUSIONS
The rate of MZTs was similar among the four ART groups. The pregnancy loss and the early miscarriage rate of MZTs was increased in IVF patients. Neither the cause of infertility nor the history of miscarriage was correlated with the risk of pregnancy loss. MZTs in the TESA group had a higher risk of TTTS, placental effects influenced by sperm and paternally expressed genes may play a role. However, due to the small total number, studies with larger sample sizes are still needed to validate these result. Pregnancy and neonatal outcomes of MZTs after PGT treatment seem to be reassuring but the duration of the study was short, and long-term follow-up of the children is needed.
Topics: Female; Humans; Infant, Newborn; Male; Pregnancy; Abortion, Spontaneous; Embryo Transfer; Fertilization in Vitro; Infertility; Placenta; Pregnancy Rate; Retrospective Studies; Semen; Twins, Monozygotic
PubMed: 37268975
DOI: 10.1186/s12958-023-01104-7