Abstract Background In recent years, several twin studies adopted a dimensional approach to Autism Spectrum Disorders (ASD) and estimated the contribution of genetic and environmental influences to ...variation in autistic traits. However, no study was performed on adults over 18 years of age and all but two studies were based on parent or teacher ratings. Also, the genetic and environmental contributions to the interplay between autistic traits and adult personality dimensions have not been investigated. Methods A sample of 266 complete twin pairs (30% males, mean age 40 ± 12 years) drawn from the population-based Italian Twin Register was administered the Autism-Spectrum Quotient, Temperament and Character Inventory (TCI-125), and General Health Questionnaire (GHQ-12). Genetic structural equation modelling was performed with the Mx program. Estimates were adjusted for gender, age, and GHQ-12 score. Results Genetic factors accounted for 44% and 20%–49% of individual differences in autistic traits and TCI dimensions, respectively. Unshared environmental factors explained the remaining proportion of variance. Consistently with the notion of a personality profile in ASD characterised by obsessive temperament, autistic traits showed significant phenotypic correlations with several TCI dimensions (positive: HA; negative: NS, RD, SD, C). Genetic and unshared environmental correlations between AQ and these TCI dimensions were significant. The degree of genetic overlap was generally greater than the degree of environmental overlap. Conclusions Despite some limitations, this study suggests that genetic factors contribute substantially to individual differences in autistic traits in adults, with unshared environmental influences also playing an important role. It also suggests that autistic traits and the majority of temperament and character dimensions share common genetic and environmental aetiological factors.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The elasticity of the internal jugular vein (IJV) is a major determinant of cerebral venous drainage and right atrium venous return. However, the level of genetic determination of IJV dimensions, ...compliance and distensibility has not been studied yet.
170 adult Caucasian twins (43 monozygotic MZ and 42 dizygotic DZ pairs) were involved from the Italian twin registry. Anteroposterior and mediolateral diameters of the IJV were measured bilaterally by ultrasonography. Measurements were made both in the sitting and supine positions, with or without Valsalva maneuver. Univariate quantitative genetic modeling was performed.
Genetic factors are responsible for 30-70% of the measured properties of IJV at higher venous pressure even after adjustment for age and gender. The highest level of inheritance was found in the supine position regarding compliance (62%) and venous diameter during Valsalva (69%). Environmental and measurement-related factors instead are more important in the sitting position, when the venous pressure is low and the venous lumen is almost collapsed. The range of capacity changes between the lowest and highest intraluminal venous pressure (full distension range) are mainly determined by genetic factors (58%).
Our study has shown substantial heritability of IJV biomechanics at higher venous pressures even after adjustment for age and gender. These findings yield an important insight to what degree the geometric and elastic properties of the vascular wall are formed by genetic and by environmental factors in humans.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The Italian National Institute of Health (Istituto Superiore di Sanità) funded a 30-month project (July 2021-January 2024) to conduct a twin study of the relationships between Positive Mental Health ...(PMH) and cellular longevity. Only a few previous studies have focused on the biomarkers of aging in relation to psychological well-being, and none of them exploited the potential of the twin design.
In this project, following the standard procedures of the Italian Twin Registry (ITR), we aim to recruit 200 adult twin pairs enrolled in the ITR. They are requested to complete a self-report questionnaire battery on PMH and to undergo a blood withdrawal for the assessment of aging biomarkers, i.e., telomere length and mitochondrial DNA functionality. The association between psychological and aging biomarker measures will be assessed, controlling for genetic and familial confounding effects using the twin study design.
Biomarker assays are underway. Once data are available for the total study sample, statistical analyses will be performed. The project's results may shed light on new mechanisms underlying the mind-body connection and may prove helpful to promote psychological well-being in conjunction with biological functioning.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
ABSTRACT
BACKGROUND AND PURPOSE
In contrast with the carotid arteries, the vertebral arteries (VAs) show considerable variation in length, caliber, and vessel course. This study investigated whether ...the variation in diameter and flow characteristics of the VAs might be inherited.
METHODS
A total of 172 Italian twins from Padua, Perugia, and Terni (54 monozygotic, 32 dizygotic) recruited from the Italian Twin Registry underwent B‐mode and pulsed‐wave Doppler ultrasound assessment of their VAs. VA diameters, peak systolic velocity (PSV) and end diastolic velocity (EDV) were assessed at the level of a horizontal V2 segment. Univariate quantitative genetic modeling was performed.
RESULTS
Fourteen percent of the sample had VA hypoplasia. Within pair correlation in monozygotic twins was higher than in dizygotics (.552 vs. .229) for VA diameter. Age‐ and sex‐adjusted genetic effect, under the most parsimonious model, accounted for 54.7% (95% CI: 42.2‐69.1%) of the variance of VA diameter, and unshared environmental effect for 45.3% (95% CI: 30.9‐57.8%). No heritability was found for the PSV of VA, but shared (34.1%; 95% CI: 16.7‐53.7%) and unshared (65.9%; 95% CI: 45.9‐83.1%) environmental factors determined the variance. EDV of VA is moderately genetically influenced (42.4%; 95% CI: 16.1‐64.9%) and also determined by the unshared environment (57.6%; 95% CI: 34.7‐83.7%).
CONCLUSIONS
The diameter of the VAs is moderately genetically determined. Different factors influence the PSV and EDV of VAs, which may highlight the complex hemodynamic background of VA flow and help to understand the vertebral flow anomalies found by ultrasound.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The Italian Twin Register has been in place for more than 10 years. Since its establishment, it has been focusing, on the one hand, on a continuous update of the existing information, and on the ...other hand, on new phenotypes and sample collection. Demographic data on about 140,000 twins have been updated using the municipality registries. The Italian Twin Register has been carrying out several new studies during the last few years. A birth cohort of twins, Multiple Births Cohort Study, has been started and the enrollment is ongoing. For this cohort, data on pregnancy and birth are collected, and periodical follow-ups are made. DNA is being collected for the twins and their parents. In the area of behavioral genetics, most efforts have been directed to psychological well being assessed with self-reported tools. Research on age-related traits continues with studies on arteriosclerosis development, early biomarkers in mild cognitive impairment, and the relation between lifestyle habits and mutagen sensitivity. The Italian Twin Register biobanking has grown in its size and in its know-how in terms of both technical issues and ethical procedures implementation. Furthermore, attitudes toward biobank-based research, together with willingness and motivation for donation, are being investigated. A valuable key resource for the Italian Twin Register is the possibility of linking twin data with disease registries. This approach has been yielding several important results, such as the recent study on the heritability of type 1 diabetes.
•One of the few longitudinal studies on mental health problems related to COVID-19.•Depressive symptoms occurring from immediately before to immediately after lockdown.•Socio-demographic and cultural ...characteristics are associated to depressive symptoms.
Italy was one of the first countries to be heavily hit by the spread of the new Coronavirus. Longitudinal studies are needed to investigate the real effect of COVID-19 on adult mental health. The Italian Twin Registry carried out a study to investigate, over time, the course of depressive symptoms in the general population.
The study relies on data collected just before the beginning (February 2020) and the end (June 2020) of the first lockdown. Symptoms of depression were assessed using the Patient Health Questionnaire, and total scores or categorized depression scores were considered in the analyzes.
A total of 1690 adult twins were recruited. The study showed a mean depression score of 1.11 immediately before lockdown and 1.20 immediately after, with an overall prevalence of depressive symptoms increasing from 33.6 to 38.9%. Depressive symptoms immediately after the restriction period were associated with Covid-19 symptoms affecting households, financial problems due to the pandemic and poor social support. Independently of the baseline risk of depressive symptoms, we observed an increased risk among younger and less educated people. Compared to the pre-lockdown period, women and middle-aged people also were found to be at greater risk of developing depressive symptoms.
Possible participation bias and residual selection bias.
The study shows that the COVID-19 pandemic was associated with an increased depressive symptomatology and that, in such health emergency times, the most vulnerable persons are young adults, women, and those living in a socially, culturally, or economically disadvantaged environment.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Summary Background An association between reduced lung function and increased cardiovascular risk has been reported, but the underlying mechanisms are unknown. The aim of this study was to assess the ...heritability of lung function and to estimate its genetic association with arterial stiffness. Methods 150 monozygotic and 42 dizygotic healthy Hungarian and American Caucasian twin pairs (age 43 ± 17 years) underwent spirometry (forced vital capacity/FVC/, forced expiratory volume in 1 s/FEV1 /; MIR Minispir, USA); and their brachial and central augmentation indices (AIx), and aortic pulse wave velocity (PWV) were measured by oscillometric Arteriograph (TensioMed Ltd, Budapest, Hungary). Phenotypic correlations and bivariate Cholesky decomposition models were applied. Results Age-, sex-, country- and smoking-adjusted heritability of FEV1 , percent predicted FEV1 , FVC and percent predicted FVC were 73% (95% confidence interval /CI/: 45–85%), 28% (95% CI: 0–67%), 68% (95% CI: 20–81%) and 45% (95% CI: 0–66%), respectively. Measured and percent predicted FVC and FEV1 values showed no significant phenotypic correlations with AIx or aortic PWV, except for phenotypic twin correlations between measured FEV1 , FVC with brachial or aortic augmentation indices which ranged between −0.12 and −0.17. No genetic covariance between lung function and arterial stiffness was found. Conclusions Lung function is heritable and the measured FVC and FEV are phenotypically, but not genetically, associated with augmentation index, a measure of wave reflection. This relationship may in turn reveal further associations leading to a better mechanistic understanding of vascular changes in various airway diseases.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Background: the genetic and environmental origins of individual differences in specific cognitive abilities in the elderly are poorly understood. One reason is the lack of studies performed in ...cohorts with normal cognitive functions. Objective: to estimate the relative contributions of genetic and environmental factors in determining inter-individual variation in neurocognitive abilities in the Italian population. Design: cross-sectional analysis of twin data. Setting: a sample of older twins with normal cognition from the population-based Italian Twin Registry (ITR). Subjects: twin pairs resident in Rome and born between 1926 and 1940, identified through the ITR in 2002. The final study population included 93 twin pairs. Methods: subjects underwent neuropsychological tests providing information about different cognitive domains. The contributions of genetic and environmental effects were assessed using standard univariate twin modelling based on linear structural equations. Results: the best-fitting model incorporated additive genetic (A) and unique environmental (E) sources of variance for the following tests: Mini-Mental State Examination (A = 55%), Raven (A = 56%), Attentional Matrices (A = 79%), Copying Drawings (A = 69%) and Story Recall (A = 54%). For Phonological and Semantic Verbal Fluency, the best model included non-additive (D) and unique environmental influences (D = 62 and 54%, respectively). Cigarette smoking was estimated to be negatively associated with the score of Phonological Verbal Fluency. For Token test, the inter-individual variance was entirely due to environmental factors not shared by the twins. Conclusion: our data showed that most of the specific cognitive abilities are moderately to highly heritable, and that the environmental factors of relevance for these abilities are those causing within-family differences.
Our study examined the use of green spaces before and during the pandemic in a large cohort of Italian twins and evaluated its impact on measures of mental health (depressive, anxiety, stress ...symptoms). Twins were analysed as individuals and as pairs. A twin design approach was applied to minimize confounding by genetic and shared environmental factors. Questionnaires from 2,473 twins enrolled in the Italian Twin Registry were screened. Reduced green space use was associated with significantly higher levels of depression, anxiety and distress. Being a woman, residing in urban areas, and having a high perceived risk of the outbreak resulted in a higher likelihood to modify green space use, with a negative impact on mental health.
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•Reduced green exposure resulted in higher levels of depression, anxiety, and distress.•Being a woman resulted in a higher likelihood to reduce free time spent outdoors.•The younger age group showed reduced use of green spaces.•Higher perceived COVID-19 risk was associated with increased stress/anxiety symptoms.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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