NCube/papyrus huggingface dataset:
Genetic and environmental influences on height from infancy to early adulthood : an individualbased pooled analysis of 45 twin cohorts

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.

Keyphrases: Epidemiology, Quantitative trait
Does cortisol moderate the environmental association between peer victimization and depression symptoms? a genetically informed twin study

Many youths who are victimized by peers suffer from depression symptoms. However, not all bullying victims become depressed and individuals’ biological sensitivity may play an important moderating role in this regard. In line with this notion, peer victimization has been associated with increased depressive symptoms in youth with higher basal cortisol secretion. It is unclear, however, whether this moderating effect of cortisol really concerns the environmental effect of peer victimization on depression. Indeed, genetic factors can also influence individuals’ environmental experiences, including peer victimization, and part of these genetic factors may be those associated with depression. Using a genetically informed design based on 159 monozygotic and 120 dizygotic twin pairs (52% girls) assessed at age 14 years, this study examined whether cortisol secretion moderates the environmental or the genetic association between peer victimization and depression symptoms. Salivary cortisol at awakening was obtained with buccal swabs during four school week days. Peer victimization and depression were assessed via self-reports. Cholesky modeling revealed that peer victimization was associated with depression symptoms via both genetic and environmental pathways. Moreover, the environmental association between peer victimization and depression symptoms steadily increased with increasing levels of morning cortisol. The genetic association between peer victimization and depression symptoms also varied, albeit less, as a function of individuals’ cortisol secretion. These findings support the hypothesis that peer victimization increases internalizing psychopathology mainly in youth with heightened biological reactivity to environmental conditions.

Keyphrases: Peer Victimization, Depression Symptoms, Cortisol Secretion, Behavioral Genetics, Adolescents
Longitudinal links between gambling participation and academic performance in youth : a test of four models

Gambling participation and low academic performance are related during adolescence, but the causal mechanisms underlying this link are unclear. It is possible that gambling participation impairs academic performance. Alternatively, the link between gambling participation and low academic performance could be explained by common underlying risk factors such as impulsivity and socio-family adversity. It could also be explained by other current correlated problem behaviors such as substance use. The goal of the present study was to examine whether concurrent and longitudinal links between gambling participation and low academic performance exist from age 14 to age 17 years, net of common antecedent factors and current substance use. A convenience sample of 766 adolescents (50.6% males) from a longitudinal twin sample participated in the study. Analyses revealed significant, albeit modest, concurrent links at both ages between gambling participation and academic performance. There was also a longitudinal link between gambling participation at age 14 and academic performance at age 17, which persisted after controlling for age 12 impulsivity and socio-family adversity as well as current substance use. Gambling participation predicts a decrease in academic performance during adolescence, net of concurrent and antecedent personal and familial risk factors.

Keyphrases: Gambling participation, Academic performance, Impulsivity, Socio-family risk, Substance use, Adolescence
Twin classroom dilemma : to study together or separately?

There is little research to date on the academic implications of teaching twins in the same or different classroom. Consequently, it is not clear whether twin classroom separation is associated with positive or negative educational outcomes. As a result, parents and teachers have insufficient evidence to make a well-informed decision when twins start school. This study addresses two research questions: Are there average positive or negative effects of classroom separation? Are twins taught in different classes more different from each other than twins taught in the same class? Twin pairs from two large representative samples from Quebec (Canada) and the United Kingdom were evaluated across a large age range (7 to 16 years) on academic achievement, several cognitive abilities and motivational measures. Our results show almost no sizable positive or negative average effect of classroom separation on twins' achievement, cognitive ability and motivation. Twin pairs at age 12 (Quebec, Canada) and at age 16 (United Kingdom) were slightly more similar on achievement if placed in the same classroom, with slightly greater similarity among monozygotic twins than dizygotic twins. However, the few effects found were weak, and it remains unclear whether they result from classroom separation or other factors. These results suggest that in terms of educational outcomes, policymakers should not impose rigid guidelines to separate twin pairs during their education. The choice of whether to educate twin pairs together or separately should be up to parents, twins and teachers, in response to twins' individual needs.

Keyphrases: Twins, Classroom separation, Academic achievement, Motivation, Cognitive abilities, Educational policies
The moderating role of peer norms in the associations of social withdrawal and aggression with peer victimization

This study examined the moderating role of classroom injunctive norms salience regarding social withdrawal and regarding aggression in the longitudinal association between these behaviors and peer victimization. A total of 1,769 fourth through sixth graders (895 girls, M = 10.25 years, SD = 1.03) from 23 schools (67 classrooms) completed a peer nomination inventory in the fall (T1) and spring (T2) of the same academic year. Participants circled the name of each student who fit the description provided for social withdrawal, aggression, and peer victimization at T1 and T2. The salience of injunctive norms was sex-specific and operationalized by the extent to which children displaying the behavior were socially rewarded or sanctioned by their classmates. Generalized estimation equations (GEE) showed that the association between social withdrawal at T1 and peer victimization at T2 was moderated by injunctive norms. Social withdrawal at T1 was positively associated with peer victimization at T2 in classrooms where injunctive norms for this behavior were salient and unfavorable, as well as in classrooms where injunctive norms for aggression were salient and favorable, albeit for girls only. The association between aggression at T1 and peer victimization at T2 was also moderated by the injunctive norms regarding this behavior. Aggressive children were less likely to be victimized in classrooms where this behavior was rewarded. These results support bullying interventions that target factors related to the larger peer context, including social norms.

Keyphrases: Social withdrawal, Peer victimization, Aggression, Salience of injunctive norms, Childhood
Phenotypic and genetic associations between reading comprehension, decoding skills, and ADHD dimensions : evidence from two population-based studies

BACKGROUND:  The phenotypic and genetic associations between decoding skills and ADHD dimensions have been documented but less is known about the association with reading comprehension. The aim of the study is to document the phenotypic and genetic associations between reading comprehension and ADHD dimensions of inattention and hyperactivity/impulsivity in early schooling and compare them to those with decoding skills. METHODS:  Data were collected in two population-based samples of twins (Quebec Newborn Twin Study - QNTS) and singletons (Quebec Longitudinal Study of Child Development - QLSCD) totaling ≈ 2300 children. Reading was assessed with normed measures in second or third grade. Teachers assessed ADHD dimensions in kindergarten and first grade. RESULTS:  Both decoding and reading comprehension were correlated with ADHD dimensions in a similar way: associations with inattention remained after controlling for the other ADHD dimension, behavior disorder symptoms and nonverbal abilities, whereas associations with hyperactivity/impulsivity did not. Genetic modeling showed that decoding and comprehension largely shared the same genetic etiology at this age and that their associations with inattention were mostly explained by shared genetic influences. CONCLUSION:  Both reading comprehension and decoding are uniquely associated with inattention through a shared genetic etiology.

Keyphrases: Reading, Comprehension, Decoding, Hyperactivity/impulsivity, Inattention, Population-based studies
Intimate partner violence and new-onset depression : a longitudinal study of women's childhood and adult histories of abuse

Background—Studies indicate that women victims of intimate partner violence are at increased risk for poor mental health. This research disentangled the effect of partner violence on new-onset depression and psychosis spectrum symptoms from effects of child maltreatment and other confounding factors, including substance abuse and antisocial personality. Methods—Participants were 1,052 mothers involved in the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally representative cohort of families followed prospectively. To test the directionality of associations between partner violence and depression, only women without a history of depression at the beginning of the study were considered (n = 978). Partner violence and mental health were assessed during face-to-face interviews with women across three time points. Results—Four of 10 women reported being the victim of violence from their partner in a 10-year period. They represent 33% of our cohort and they account for 51% of new-onset depression. These women had a twofold increase in their risk of suffering from new-onset depression once the effect of childhood maltreatment, socioeconomic deprivation, antisocial personality, and young motherhood were controlled. Women who were abused both in childhood and adulthood were four to seven times more likely to suffer from depression than never-abused women. We observed similar associations with psychosis spectrum symptoms. Conclusions—Women victims of partner violence account for more than their share of depression. Findings strengthen existing evidence that partner violence independently contributes to women’s poor mental health. Psychological difficulties among a considerable number of women could be reduced by stopping partner violence.

Keyphrases: Depression, Partner violence, Interpersonal violence, Victimization, Women, Longitudinal study
The interactive effects of parental knowledge with impulsivity and sensation seeking in adolescent substance use

This study examined whether interactions of parental knowledge of adolescent’s whereabouts with impulsivity and sensation seeking in the prediction of adolescent substance use supported the diathesis–stress or differential susceptibility model in 230 15-year old adolescents (53% girls). Interactions between impulsivity and parental knowledge supported the diathesis–stress model with high impulsivity as a vulnerability factor: when impulsivity was higher, low levels of parental knowledge were associated with higher levels of substance use. Interactions between sensation seeking and parental knowledge supported differential susceptibility with low sensation seeking as a susceptibility factor; low parental knowledge was associated with higher substance use and high parental knowledge with lower substance use when sensation seeking was lower. Our results show that impulsivity and sensation seeking should be considered independently. Results support previous research suggesting that impulsivity in adolescence may act as a vulnerability factor and suggests that low sensation seeking may be a susceptibility factor.

Keyphrases: Personality, Monitoring, Alcohol, Drugs, Moderation
Interactive effects of early and recent exposure to stressful contexts on cortisol reactivity in middle childhood

Background: Given mixed findings as to whether stressful experiences and relationships are associated with increases or decreases in children’s cortisol reactivity, we tested whether a child’s developmental history of risk exposure explained variation in cortisol reactivity to an experimentally induced task. We also tested whether the relationship between cortisol reactivity and children’s internalizing and externalizing problems varied as a function of their developmental history of stressful experiences and relationships. Method: Participants included 400 children (M = 9.99 years, SD = 0.74 years) from the Children’s Experiences and Development Study. Early risk exposure was measured by children’s experiences of harsh, nonresponsive parenting at 3 years. Recent risk exposure was measured by children’s exposure to traumatic events in the past year. Children’s cortisol reactivity was measured in response to a social provocation task and parents and teachers described children’s internalizing and externalizing problems. Results: The effect of recent exposure to traumatic events was partially dependent upon a child’s early experiences of harsh, nonresponsive parenting: the more traumatic events children had recently experienced, the greater their cortisol reactivity if they had experienced lower (but not higher) levels of harsh, nonresponsive parenting at age 3. The lowest levels of cortisol reactivity were observed among children who had experienced the most traumatic events in the past year and higher (vs. lower) levels of harsh, nonresponsive parenting in early childhood. Among youth who experienced harsh, nonresponsive parent–child relationships in early childhood and later traumatic events, lower levels of cortisol reactivity were associated with higher levels of internalizing and externalizing problems. Conclusions: Hypothalamic–pituitary–adrenal (HPA) axis reactivity to psychological stressors and the relationship between HPA axis reactivity and children’s internalizing and externalizing problems vary as a function of a child’s developmental history of exposure to stressful relationships and experiences.

Keyphrases: Cortisol reactivity, Stress, Parenting, Internalizing, Externalizing
Previous pregnancy outcomes and subsequent pregnancy anxiety in a Quebec prospective cohort

Introduction— Pregnancy anxiety is an important psychosocial risk factor that may be more  strongly associated with adverse birth outcomes than other measures of stress. Better  understanding of the upstream predictors and causes of pregnancy anxiety could help to identify  high-risk women for adverse maternal and infant outcomes. The objective of the present study was  to measure the associations between five past pregnancy outcomes (live preterm birth (PTB), live  term birth, miscarriage at <20 weeks, stillbirth at ≥20 weeks, and elective abortion) and pregnancy  anxiety at three trimesters in a subsequent pregnancy. Methods— Analyses were conducted using data from the 3D Cohort Study, a Canadian birth  cohort. Data on maternal demographic characteristics and pregnancy history for each known  previous pregnancy were collected via interviewer-administered questionnaires at study entry.  Pregnancy anxiety for the index study pregnancy was measured prospectively by self-administered  questionnaire following three prenatal study visits. Results— Of 2366 participants in the 3D Study, 1505 had at least one previous pregnancy. In  linear regression analyses with adjustment for confounding variables, prior live term birth was  associated with lower pregnancy anxiety in all three trimesters, whereas prior miscarriage was  significantly associated with higher pregnancy anxiety in the first trimester. Prior stillbirth was  associated with greater pregnancy anxiety in the third trimester. Prior elective abortion was significantly associated with higher pregnancy anxiety scores in the first and second trimesters,  with an association of similar magnitude observed in the third trimester. Discussion— Our findings suggest that the outcomes of previous pregnancies should be  incorporated, along with demographic and psychosocial characteristics, into conceptual models  framing pregnancy anxiety.

Keyphrases: Pregnancy, Anxiety, Perinatal mental health, Adverse pregnancy outcomes, Perinatal loss
Complex effects of dyslexia risk factors account for ADHD-traits : evidence from two independent samples

Background: Developmental dyslexia (DD) and attention deficit/hyperactivity disorder (ADHD) are among the most common neurodevelopmental disorders, whose etiology involves multiple risk factors. DD and ADHD co-occur in the same individuals much more often than would be expected by chance. Several studies have found significant bivariate heritability, and specific genes associated with either DD or ADHD have been investigated for association in the other disorder. Moreover, there are likely to be gene-by-gene and gene-by-environment interaction effects (GxG and GxE, respectively) underlying the comorbidity between DD and ADHD. We investigated the pleiotropic effects of 19 SNPs spanning five DD genes (DYX1C1, DCDC2, KIAA0319, ROBO1 and GRIN2B) and seven DD environmental factors (smoke, miscarriage, birth weight, breastfeeding, parental age, socioeconomic status and parental education) for main, either 1) genetic or 2) environmental, 3) G×G, and 4) G×E upon inattention and hyperactivity/impulsivity. We then attempted replication of these findings in an independent twin cohort. Methods: Marker-trait association was analyzed by implementing the Quantitative Transmission Disequilibrium Test (QTDT). Environmental associations were tested by partial correlations. GxG were investigated by a general linear model equation and a family-based association test. GxE were analyzed through a general test for GxE in sib-pair-based association analysis of quantitative traits. Results: DCDC2-rs793862 was associated with hyperactivity/impulsivity via G×G (KIAA0319) and G×E (miscarriage). Smoke was significantly correlated with hyperactivity/impulsivity. We replicated the DCDC2×KIAA0319 interaction upon hyperactivity/impulsivity in the twin cohort. Conclusions: DD genetic (DCDC2) and environmental factors (smoke and miscarriage) underlie ADHD-traits supporting a potential pleiotropic effect.

Keyphrases: Developmental dyslexia, ADHD, Association study, Gene-by-environment interaction, Pleiotropy, Gene-by-gene interaction
The genetic and environmental etiology of the association between vocabulary and syntax in first grade

This study examined the genetic and environmental etiology of vocabulary, syntax, and their association in first graders. French-speaking same-sex twins (N = 555) completed two vocabulary tests, and two scores of syntax were calculated from their spontaneous speech at 7 years of age. Multivariate latent factor genetic analyses showed that lexical skills were influenced mainly by the environment shared between the twins, whereas syntactic skills were influenced exclusively by genes and unique environment. Moreover, the moderate association between vocabulary and syntax was mostly due to common genetic factors. These novel findings may be attributable to the use of latent factors and the population studied. More research is needed to determine the specific factors involved in lexical and syntactic skills at this developmental period.

Keyphrases: Vocabulary, Syntax, Behavioural genetics, School entry
Similarities and differences between behavioral and electrophysiological visual acuity thresholds in healthy infants during the second half of the first year of life

Purpose Behavioral and electrophysiological methods for visual acuity estimation typically correlate well in children and adult populations, but this relationship remains unclear in infants, particularly during the second half of the first year of life. It has been suggested that the agreement between both methods mostly relies on age and/or subjective acuity factors. The present study aimed at comparing acuity thresholds obtained with both approaches in a sample of healthy infants in a relatively narrow age range, that is 6–10 months old. Methods Acuity thresholds were assessed in 61 healthy infants aged between 6 and 10 months using the Teller acuity cards (TAC) and sweep visual evoked potentials (sVEP). The TAC stimuli (stationary vertical gratings displayed on laminated cards) ranged from 0.31 to 38 cycles per degree (cpd). The TAC acuity threshold was estimated according to the highest spatial frequency scored by the experimenter as seen by the infant. The sVEP stimuli (high-contrast vertical gratings counter-phased at 12 reversals/s) ranged from 13.5 to 1 cpd. sVEP were recorded at Oz and acuity threshold was estimated using regression linear fitting. Results Considering the entire sample, sVEP acuity thresholds (8.97 ± 2.52 cpd) were significantly better than TAC scores (5.58 ± 2.95 cpd), although the difference was within 1 octave for 64% of the infants. Neither Pearson nor intra-class correlations between the two methods were significant (0.18 and 0.03, respectively). While age at assessment was not related to any dependent variable (TAC, sVEP, sVEP–TAC difference score), subjective (behavioral) acuity was found to underlie the difference between the two methods. The difference between sVEP and TAC scores decreased as a function of subjective acuity, and at the highest subjective acuity level (>10 cpd), TAC acuity slightly exceeded sVEP acuity. Conclusions The superiority of sVEP acuity often reported in the literature was evident in our infant sample when subjective acuity (TAC) was low or moderate, but not when it was high (>10 cpd). The relationship between the two estimation methods was not dependent on age, but on subjective acuity.

Keyphrases: Visual acuity, Teller acuity cards, Sweep visual evoked potentials, Infant