Early-life positive and adverse parental factors, such as positive parent personality and parental stress, affect the environmental context in which children develop and may influence individual differences in children\'s sleep health. This study examined the moderating role of early-life parental factors in the heritability (i.e., the extent to which individual differences are due to genetic influences) of objectively assessed childhood sleep duration. A total of 351 families from the Arizona Twin Project were studied. Primary caregivers (95% mothers) reported on multiple dimensions of stress and facets of their own personality when the twins were 12 months old. Seven years later (Mage = 8.43 years, SD = 0.68), families completed a home visit, and twins (51% female; 57% White, 29% Hispanic; 30% monozygotic, 39% same-sex dizygotic, 31% other-sex dizygotic) wore actigraph watches to assess their sleep, with caregivers completing similar assessments on their personality attributes and stress. Early-life positive parent personality moderated the heritability of sleep duration (Δ-2LL [-2 log likelihood] = 2.54, Δdf = 2, p = .28), such that as positive parent personality increased, the heritability of duration decreased. Early-life parental stress also moderated the genetic contribution to sleep duration (Δ-2LL = 2.02, Δdf = 2, p = .36), such that as stress increased, the heritability of duration increased. Concurrent positive parent personality and parental stress composites showed similar patterns of findings. Results highlight the likely contribution of parent positive traits and adverse experiences to the etiology of children\'s sleep health, with genetic influences on children\'s sleep more prominent in \"riskier\" environments. Understanding how genetics and environments work together to influence the etiology of sleep may inform prevention programs.

BACKGROUND: Epigenetic clocks were known as promising biomarkers of aging, including original clocks trained by individual CpG sites and principal component (PC) clocks trained by PCs of CpG sites. The effects of genetic and environmental factors on epigenetic clocks are still unclear, especially for PC clocks.
METHODS: We constructed univariate twin models in 477 same-sex twin pairs from the Chinese National Twin Registry (CNTR) to estimate the heritability of five epigenetic clocks (GrimAge, PhenoAge, DunedinPACE, PCGrimAge, and PCPhenoAge). Besides, we investigated the longitudinal changes of genetic and environmental influences on epigenetic clocks across 5 years in 134 same-sex twin pairs.
RESULTS: Heritability of epigenetic clocks ranged from 0.45 to 0.70, and those for PC clocks were higher than those for original clocks. For five epigenetic clocks, the longitudinal stability was moderate to high and was largely due to genetic effects. The genetic correlations between baseline and follow-up epigenetic clocks were moderate to high. Special unique environmental factors emerged both at baseline and at follow-up. PC clocks showed higher longitudinal stability and unique environmental correlations than original clocks.
CONCLUSIONS: For five epigenetic clocks, they have the potential to identify aging interventions. High longitudinal stability is mainly due to genetic factors, and changes of epigenetic clocks over time are primarily due to changes in unique environmental factors. Given the disparities in genetic and environmental factors as well as longitudinal stability between PC and original clocks, the results of studies with original clocks need to be further verified with PC clocks.

BACKGROUND: Strategies of prevention for psychiatric disorders need a deep understanding of the aetiological factors involved in the psychopathological processes. Our twin study aims at disentangling the contributions of genes and environment to schizotypal and hypomanic dimensions, considering the role of stressful life events (LEs) and the quality of family relationships.
METHODS: The Magical Ideation Scale (MIS) and Perceptual Aberration Scale (PAS) were used to assess positive schizotypy, while Hypomanic Personality Scale (HPS) and its sub-scales were used to investigate proneness to affective disorders. 268 twins (54.5 % female; aged 18.0 ± 6.68) were included. Participants filled out a questionnaire on LEs and their parents provided an evaluation of intra-family relationship (Relationship Quality Index, RQI). Classic univariate twin models for quantitative traits were fitted for scales, and the effects of covariates (LEs and RQI) were assessed.
RESULTS: For MIS, HPS and its sub-scales, significant common and unique environmental effects were detected, with genetic factors affecting only HPS Social Vitality sub-scale. Unique environment was the only source of variance of PAS score. The number of recent LEs influenced MIS and PAS models, while RQI score affected MIS model.
CONCLUSIONS: The main limitation of the study is the small sample size, which reduces statistical power and may potentially lead to an underestimation of heritability. Additionally, the cross-sectional design limits the possibility to draw causal considerations.
CONCLUSIONS: Findings provide preliminary evidence for a significant environmental role in modulating states of vulnerability. Moreover, the expression of positive schizotypy resulted influenced by recent stressors and intra-family relationships.

Social science research argues that differences in individuals\' literary and cultural tastes originate in social environments. Yet, it might be that these differences are partly associated with genetic differences between individuals. To address this possibility, we use nation-scale registry data on library borrowing among Danish twins (N = 67,900) to assess the heritability of literary tastes. We measure literary tastes via borrowing of books of different genres (e.g., crime and biographical novels) and formats (physical, digital, and audio) and decompose the total variance in literary tastes into components attributable to shared genes (heritability), shared environments (social environment shared by siblings), and unique environments (social environments not shared by siblings). We find that genetic differences account for 45-70 percent of the total variance in literary tastes, shared environments account for almost none of the variance, and unique environments account for a moderate share. These results suggest that literary tastes are approximately as heritable as other human phenotypes (e.g., physical traits, cognition, and health). Moreover, heritability is higher for socioeconomically disadvantaged groups than for advantaged groups. Overall, our results suggest that research should consider the role of genetic differences in accounting for individual differences in literary and broader cultural tastes.

The aim of this study is to investigate the mediating role of sleep quality in the relationship between multidimensional perceived social support and fatigue among mothers of twin infants. One hundred and six (106) twin mothers participated in this cross-sectional study, who completed the Descriptive Information Form, Multidimensional Scale of Perceived Social Support, Pittsburgh Sleep Quality Index, and Checklist Individual Strength. The scale score averages of the mothers in the study are as follows: social support, 61.41 ± 23.86; fatigue, 77.64 ± 28.68; and sleep quality, 8.26 ± 2.38. According to the path model, perceived social support has a negative effect on poor sleep quality (p = .001, Beta = -0.411), and poor sleep quality has a positive effect on fatigue (p = .001, Beta = 0.335). Sleep quality also mediates the effect of multidimensional perceived social support on mothers\' fatigue levels (p = .001, Beta = -0.138). The study results suggest that the perceived social support and fatigue levels of twin mothers are moderate, while their sleep quality is poor. Therefore, mothers of twin infants may benefit from increased social support to alleviate fatigue and enhance sleep quality.

BACKGROUND: Adolescents raised in families with different maternal and paternal parenting combinations exhibit variations in neurocognition and psychopathology; however, whether neural differences exist remains unexplored. This study used a longitudinal twin sample to delineate how different parenting combinations influence adolescent brain structure and to elucidate the genetic contribution.
METHODS: A cohort of 216 twins participated in parenting assessments during early adolescence and underwent MRI scanning during middle adolescence. We utilized latent profile analysis to distinguish between various maternal and paternal parenting profiles and subsequently investigated their influences on brain anatomy. Biometric analysis was applied to assess the genetic influences on brain structure, and associations with internalizing symptoms were explored.
RESULTS: In early adolescence, four parenting profiles emerged characterized by levels of harshness and hostility in one or both parents. Compared to adolescents in \"catparent\" families (low harshness/hostility in both parents), those raised in \"tigermom\" families (harsh/hostile mother only) exhibited smaller nucleus accumbens volume and larger temporal cortex surface area; those in \"tigerdad\" families demonstrated larger thalamus volumes; those in \"tigerparent\" families displayed smaller volumes in the mid-anterior corpus callosum. Genetic risk factors contributed significantly to the observed brain structural heterogeneity and internalizing symptoms. However, the influences of parenting profiles and brain structure on internalizing symptoms were not significant.
CONCLUSIONS: The findings underscore distinct brain structural features linked to maternal and paternal parenting combinations, particularly in terms of subcortical volume and cortical surface area. This study suggests an interdependent role of maternal and paternal parenting in shaping adolescent neurodevelopment.

OBJECTIVE: To systematically review the literature regarding the concordance of sleep bruxism (SB) between monozygotic (MZ) and dizygotic (DZ) twins.
METHODS: The registration for this systematic review was accomplished in the International Prospective Register of Systematic Reviews (PROSPERO, No. CRD42021251751). As of July 2022, four databases were searched, including PubMed, Scopus, Embase, and Web of Science, as well as the grey literature in Google Scholar and OpenGrey. Observational studies evaluating SB in MZ and DZ twins of any age and sex were included. For the evaluation of the risk of bias, the Joanna Briggs checklist was utilized. The certainty of evidence was assessed via the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Pooled and subgroup meta-analyses were performed to estimate concordance of SB ​​between twins (p < 0.05).
RESULTS: In total, 3,155 records were identified. In the qualitative analysis, eleven studies were included; of these, seven were included in the meta-analysis. The majority of the articles exhibited a low risk of bias (63.6%). Greater SB concordance was observed between MZ twins than between DZ twins in the analysis of general concordance (OR = 1.47; 95% CI = 1.07-2.02) and also positive concordance (OR = 1.53; 95% CI = 1.29-1.81). Within the subgroup analyses, the significance of the findings remained only for the reported/self-reported SB regarding general concordance (OR = 1.44; 95% CI = 1.07-1.95) and positive concordance (OR = 1.55; 95% CI = 1.28-1.88). Low certainty of the evidence was observed for the general concordance analysis, while moderate certainty was observed for the positive concordance.
CONCLUSIONS: There was a higher concordance of SB in MZ twins compared to DZ twins, indicating a possible genetic influence on the condition\'s occurrence.

Twin pregnancy in cattle is undesirable for a number of reasons, including a higher abortion risk compared to pregnancies with a single foetus. Yet, the abortion risk is significantly influenced by the intrauterine location of the foetuses, that is, the abortion risk is several times higher if they are implanted in the same uterine horn (unilateral twin pregnancy) than if they are implanted with one foetus in each uterine horn (bilateral twin pregnancy). The reason for the higher abortion risk in unilateral twin pregnancies is unknown, but it may be related to malnutrition of the outermost foetus due to a limited placental capacity, as is the case for equine twin foetuses. A slaughterhouse study was performed and the foetuses of cattle pregnant with twins were measured. We identified 65 cases of twin pregnancies, of which 35 were unilateral twin pregnancies and 30 were bilateral twin pregnancies. There was no significant difference between the outermost and the more centrally located foetus in unilateral twin pregnancies in terms of body weight and length of the metacarpal diaphysis. Growth retardation of the outermost foetus could therefore not be confirmed as the cause of the higher abortion risk in unilateral bovine twin pregnancies. Four cases of pre-slaughter foetal mortality were identified. In three of these cases, both twins were dead, of equal size and at a comparable level of degradation. In the fourth case, with approximately 40-day-old twin foetuses of equal size, only one of the foetuses showed signs of pre-slaughter death.

OBJECTIVE: Pediatric loss-of-control (LOC) eating is associated with high BMI and predicts binge-eating disorder and obesity onset with age. Research on the etiology of this common comorbidity has not explored the potential for shared genetic risk. This study examined genetic and environmental influences on LOC eating and its shared influence with BMI.
METHODS: Participants were 499 monozygotic and 398 same-sex dizygotic twins (age = 17.38 years ± 0.67, BMIz = 0.03 ± 1.03, 54% female) from the Colorado Center for Antisocial Drug Dependence Study. LOC eating was assessed dichotomously. Self-reported height and weight were converted to BMIz. Univariate and bivariate twin models estimated genetic and environmental influences on LOC eating and BMIz.
RESULTS: More girls (21%) than boys (9%, p < 0.001) reported LOC eating. The phenotypic correlation with BMIz was 0.03 in girls and 0.18 in boys. Due to the nonsignificant phenotypic correlation in girls, bivariate twin models were fit in boys only. Across all models, the best-fitting model included genetic and unique environmental effects. Genetic factors accounted for 0.51 (95% CI: 0.23, 0.73) of the variance of LOC eating in girls and 0.54 (0.18, 0.90) in boys. The genetic correlation between LOC eating and BMIz in boys was 0.45 (0.15, 0.75).
CONCLUSIONS: Findings indicate moderate heritability of LOC eating in adolescence, while emphasizing the role of unique environmental factors. In boys, LOC eating and BMIz share a proportion of their genetic influences.

OBJECTIVE: To investigate the risk factors for bronchopulmonary dysplasia (BPD) in twin preterm infants with a gestational age of <34 weeks, and to provide a basis for early identification of BPD in twin preterm infants in clinical practice.
METHODS: A retrospective analysis was performed for the twin preterm infants with a gestational age of <34 weeks who were admitted to 22 hospitals nationwide from January 2018 to December 2020. According to their conditions, they were divided into group A (both twins had BPD), group B (only one twin had BPD), and group C (neither twin had BPD). The risk factors for BPD in twin preterm infants were analyzed. Further analysis was conducted on group B to investigate the postnatal risk factors for BPD within twins.
RESULTS: A total of 904 pairs of twins with a gestational age of <34 weeks were included in this study. The multivariate logistic regression analysis showed that compared with group C, birth weight discordance of >25% between the twins was an independent risk factor for BPD in one of the twins (OR=3.370, 95%CI: 1.500-7.568, P<0.05), and high gestational age at birth was a protective factor against BPD (P<0.05). The conditional logistic regression analysis of group B showed that small-for-gestational-age (SGA) birth was an independent risk factor for BPD in individual twins (OR=5.017, 95%CI: 1.040-24.190, P<0.05).
CONCLUSIONS: The development of BPD in twin preterm infants is associated with gestational age, birth weight discordance between the twins, and SGA birth.
目的: 分析胎龄<34周双胎早产儿发生支气管肺发育不良（bronchopulmonary dysplasia, BPD）的危险因素，为临床早期识别双胎早产儿BPD的发生提供依据。方法: 回顾性收集全国22家医院2018年1月—2020年12月收治的胎龄<34周双胎早产儿，根据双胎儿患病情况分为三组：两胎均为BPD组、仅一胎为BPD组、两胎均非BPD组，分析双胎早产儿发生BPD的危险因素；并对仅一胎为BPD组患儿进一步分析，组内配对分析双胎早产儿发生BPD的产后危险因素。结果: 共纳入胎龄<34周的双胎儿共904对。多因素logistic回归分析中，与两胎均非BPD组相比，双胎出生体重差异>25%是双胎中仅一胎患BPD的危险因素 （OR=3.370，95%CI：1.500~7.568，P<0.05），胎龄大是双胎均患BPD的保护因素（P<0.05）。对双胎中仅一胎为BPD组进行组内条件logistic回归分析，提示小于胎龄儿是双胎内个体发生BPD的危险因素（OR=5.017，95%CI：1.040~24.190，P<0.05）。结论: 双胎早产儿BPD的发生不仅与胎龄相关，也与双胎出生体重差异、小于胎龄儿密切相关。.