Arizona Twin Project: Specificity in Risk and Resilience for Developmental Psychopathology and Health

The Role of Sleep in Links Between Daily Interpersonal Stress and Internalizing and Externalizing Symptoms During Middle Childhood

Background

Interpersonal stress has been consistently linked with poorer adjustment, and healthy sleep may play a promotive or protective role in this relation. However, little is known regarding such associations among children. The current study examined longitudinal associations between daily interpersonal stress, sleep, and internalizing/externalizing symptoms during middle childhood.

Methods

At age 8 years, participants wore actigraphy watches for 7 days to capture sleep, and primary caregivers reported on children's daily interpersonal stress, internalizing/externalizing symptoms, and sleep problems. At age 9 years, children self-reported symptoms.

Results

Greater daily interpersonal stress at age 8 years predicted greater internalizing/externalizing symptoms at age 9 years. Higher sleep efficiency predicted fewer externalizing symptoms. Sleep duration moderated links between interpersonal stress and internalizing/externalizing symptoms, but associations were positive and significant for children with average and high duration only.

Conclusion

Findings advance our understanding of links between interpersonal stress, sleep, and child adjustment and can inform targeted family and school interventions.

The moderating role of early-life parental adverse and positive factors in the genetic and environmental contributions to objectively assessed sleep duration in middle childhood

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.

Cascading Influences of Caregiver Experiences of Discrimination and Adolescent Antisocial Behavior

OBJECTIVE

Although a growing body of work has found that parents' experiences of racial and socioeconomic (SES) based discrimination are directly related to their children's behavior problems , more work is needed to understand possible pathways by which these factors are related and to identify potential targets for prevention and/or intervention.

METHOD

Using a large (N = 572), longitudinal sample of low-income families from diverse racial backgrounds, the current study explored whether caregivers' experiences of racial and SES discrimination during their children's middle childhood (i.e. ages 7.5-9.5) predicted youth-reported antisocial behavior during adolescence and potential factors mediating these associations (e.g. caregiver depressive symptoms and positive parenting practices).

RESULTS

We found that higher levels of caregiver experiences of discrimination at child ages 7.5-9.5 predicted higher levels of caregiver depressive symptoms at child age 10.5, which were related to lower levels of caregiver endorsement of positive parenting practices at child age 14.5, which in turn, predicted higher levels of youth-reported antisocial behavior at age 16.

CONCLUSION

The findings highlight the adverse effects of racism and discrimination in American society. Second, the findings underscore the need to develop interventions which mitigate racism and discrimination among perpetrators and alleviate depressive symptoms among caregivers.

Concordance in parent-child and sibling actigraphy-measured sleep: Evidence among early adolescent twins and primary caregivers

STUDY OBJECTIVES

Growing evidence suggests concordance between parent and youth sleep. However, no known study has simultaneously examined concordance among siblings' sleep patterns. This study investigated daily and average concordance in (1) parent-youth and (2) sibling actigraphy-measured sleep, as well as the degree to which sibling concordance varied by sleeping arrangements.

METHODS

516 twin siblings (Mage = 10.74, 51% female; 30% monozygotic (MZ) twin pairs, 37% same-sex dizygotic pairs (DZ-ss), 33% opposite-sex DZ pairs (DZ-os)) and their primary caregivers (Mage = 40.59, 95% female) wore wrist-based accelerometers for 7 consecutive nights to measure sleep duration, efficiency, midpoint time, and latency. Primary caregivers also reported on demographics, youth pubertal status, and room-sharing. Two-level multilevel models were estimated to examine daily and average concordance in parent-youth and sibling sleep.

RESULTS

Daily concordance was observed between parent and youth sleep duration and midpoint; average concordance was found for sleep duration, midpoint, and latency. Within sibling dyads, daily and average concordance was evident across all sleep parameters (duration, efficiency, midpoint, latency), with generally stronger concordance patterns for MZ than DZ twin pairs, and for twins who shared a room with their co-twin.

CONCLUSIONS

This is the first known study to document concordance among parent-youth and siblings' actigraphy-measured sleep within the same study (i.e., triad). Our findings can help inform the development of family-level interventions targeting daily and overall sleep hygiene.

Novel measures of family orientation and childhood self-regulation: A genetically informed twin study

There is a dearth of research examining the relation between culture and childhood self-regulation in family psychology. Family orientation refers to the emphasis on providing support, respect, and obligation to the family system, and it is important for children's functioning, yet existing literature on related constructs often relies on parent-reported measures. Additionally, twin research has neglected the role of culture in the genetic and environmental contributions to children's self-regulation. Using observational and self-reported data from children, parents, and teachers, this study (a) proposed novel coding schemes and factor analytic approaches to capture family orientation, (b) examined associations between family orientation and self-regulation, and (c) tested whether family orientation moderated the heritability of self-regulation in middle childhood. Twin children (N = 710; Mage = 8.38 years, SD = 0.66; 49.1% female; 28.3% Hispanic/Latino/x, 58.5% White) were drawn from the Arizona Twin Project, which recruited children from birth records at 12 months of age. Family orientation values were indexed by parent-reported familism, and family orientation behaviors comprised coded measures of children's family orientation and experimenter ratings of caregiver and child behavior. Self-regulation was assessed using multiple task-based assessments of executive function and parent- and teacher-reported effortful control. Net of covariates, higher family orientation behaviors positively predicted nearly all measures of children's self-regulation, and associations were consistent across sex, family socioeconomic status, and race/ethnicity. There was no evidence that family orientation values nor behaviors moderated the heritability of children's self-regulation. This study highlights the complex nature of cultural variation within the family and its importance for children's self-regulatory abilities. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Genetic and environmental links between executive functioning and effortful control in middle childhood

There is a need to understand the components of self-regulation, given its link to nearly every domain of functioning across the life span. This study examined the etiological underpinnings of covariance between measures of executive functioning (EF) and effortful control (EC) in middle childhood. The extent that genetic and environmental factors explain the association between EF and EC is unknown. Families were drawn from a longitudinal twin study (N = 894 twins; Mage = 8.87 years, SD = 1.10; 51.4% female; 46.8% non-Hispanic White, 28% Latino/a/x) and twins completed EF tasks during a home visit (Flanker Task, Continuous Performance Task, and Digit Span Backward) and primary caregivers (93.8% mothers) reported on their twins' EC (Attentional Focusing and Inhibitory Control). Univariate twin models showed additive genetic and nonshared environmental influences on the Flanker Task, Continuous Performance Task, Digit Span Backward, and parent-reported Inhibitory Control, and dominant genetic influences were implicated in parent-reported Attentional Focusing. Bivariate twin models revealed that additive genetic influences explained the small covariance between EF and EC. Executive attention could explain the genetic covariance between measures of EF and EC. This study suggests that EF and EC tap into the same underlying self-regulation construct, with weak correlations between constructs being attributed to measurement, rather than conceptual, differences. Elucidating the overlap between EF and EC can bring researchers closer to understanding how best to foster adaptive self-regulation. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Does stress predict the development of internalizing symptoms in middle childhood? An examination of additive, mediated, and moderated effects of early family stress, daily interpersonal stress, and physiological stress

Early life stress, daily life experiences, and the stress responsive hypothalamic-pituitary-adrenal (HPA) axis have each been examined as predictors of the development of psychopathology. Rarely have researchers attempted to understand the covariation or interaction among these stress domains using a longitudinal design in the prediction of symptoms of internalizing psychopathology, particularly during childhood. This study examined early family stress, daily interpersonal stress, indicators of diurnal cortisol, and internalizing symptoms in a racially/ethnically and socioeconomically diverse sample of twins (N = 970 children; Mage at outcome = 9.73; 52% female; 23.7% Hispanic/Latino, 58.8% White; 30% below middle class; Lemery-Chalfant et al., 2019). An additive model of stress, a stress mediation model, and a stress sensitization framework model each delineated potential pathways linking stress and internalizing symptoms. Supporting additive pathways, multilevel models showed that all 3 stress indicators uniquely predicted internalizing symptoms. There was a significant indirect path from early family stress to 9 year internalizing symptoms through interpersonal stress, supporting stress mediation. Family stress moderated the association between interpersonal stress and internalizing symptoms, though not in the direction that would support stress sensitization. Child stress, including daily interpersonal stress and HPA axis activity, and internalizing symptoms are prevalent and family stress is a significant precursor to child internalizing symptoms across child development. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Early Life Socioeconomic Differences in Associations between Childhood Sleep and Academic Performance

Poor sleep can negatively impact children's academic performance. However, it is unknown whether early-life socioeconomic status (SES) moderates later sleep and academics. We tested associations between actigraphy-based sleep duration and midpoint time, and parent-reported sleep problems with objective and subjective measures of academic performance. We also examined whether relations varied by early and concurrent SES. Children (n=707; 52% female; M _age=8.44 years; 28.7% Hispanic/Latinx; 29.7% at/below poverty line) were assessed at 12 months for SES and eight years for SES, sleep, and academics. There were no main effects of sleep on academics. More sleep problems predicted lower Applied Problems performance for low SES children (b=-.73, p<.05) and better performance for high SES children (b=.69, p<.05). For high SES children, greater sleep problems (b=-.11, p<.05) and longer sleep duration (b=-.11, p<.05) predicted lower academic achievement. However, most associations were consistent across SES, illustrating the complex interplay between sleep, academic outcomes, and SES.

Effortful control and health among triads of mothers and twin children: An actor-partner interdependence modeling approach

Associations between effortful control and physical and mental health were examined among triads of mothers and twin children by simultaneously modeling the effects of one's own effortful control on one's own health (actor effects) with the effects of the other two family members' effortful control on one's health (partner effects). Families (N = 761 individuals; 254 families) included mothers (M_age = 39.98, SD = 5.64) and their twin children (M_age = 8.58, SD = 0.57; 51% female; 54.7% non-Hispanic White, 28% Hispanic). Mothers completed online and in-person questionnaires, and mothers' and children's body composition indicators and dominant-handgrip strength were directly assessed during two home visits. Actor effects dominated in families with twin boys and mixed-sex twins, whereas partner effects were more apparent in families with twin girls. In addition, the effects of children's effortful control on mothers' health depended on the sex of the twins. Findings uncovered important family dynamics linking effortful control to health, including that associations may vary by sex match of children in the family. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The onset of pubertal development and actigraphy-assessed sleep during middle childhood: Racial, gender, and genetic effects

OBJECTIVE

This study (1) examined pubertal development in relation to actigraphy-assessed sleep in twin children, and tested whether associations differed by child race and gender, (2) modeled genetic and environmental influences on pubertal development and sleep indicators, and (3) examined genetic and environmental influences on the covariation of puberty and sleep.

DESIGN

The classic twin design was used to examine genetic and environmental contributions to puberty and sleep and their associations.

SETTING

Data were collected from community-dwelling urban and rural families of twins in the southwestern U.S.

PARTICIPANTS

The racially and socioeconomically diverse sample included 596 twin children (M_age = 8.41, SD = 0.69; 51.7% female; 66.3% white; 33.7% Hispanic; 170 monozygotic, 236 same-sex dizygotic, 188 opposite-sex dizygotic).

MEASUREMENTS

Pubertal development was assessed via parent report. Children wore actigraph watches for 7 nights (M = 6.81, SD = 0.67) to capture sleep duration, efficiency, midpoint, onset latency, and duration variability.

RESULTS

In contrast to extant literature with older youth, more advanced pubertal development was associated with longer sleep durations in Hispanic and white girls and higher sleep efficiency in white girls, though Hispanic girls demonstrated later sleep midpoints. Pubertal development was moderately heritable and there was a genetic influence on the covariance between puberty and sleep indicators.

CONCLUSIONS

This was the first study to examine the genetic and environmental influences on the covariation between puberty and sleep, and found genetic underpinnings between pubertal development and actigraphy-assessed sleep duration and efficiency, though sleep and puberty were almost entirely independent in twins at this age.

School Readiness and Achievement in Early Elementary School: Moderation by Students' Temperament

The goals of this study were to examine the longitudinal relations between school readiness and reading and math achievement and to test if these relations were moderated by temperament. The sample included socio-economically and ethnically diverse twins (N=551). Parents reported on school readiness when children were five years old. Teachers reported on temperament (effortful control, anger, and shyness) three years later. Standardized measures of reading and math were obtained when children were eight years old. Effortful control and shyness moderated the effect of school readiness on reading. Prediction of reading from school readiness was strongest when students were high in effortful control and low in shyness. Effortful control and shyness predicted math beyond school readiness. There were no relations involving anger. Findings demonstrate that temperament can potentiate the relations between school readiness and reading and highlight the importance of promoting school readiness and effortful control, while decreasing shyness.

Pediatric recurring pain in the community: the role of children's sleep and internalizing symptoms

Associations between poor sleep and pain may be amplified for children who also have depressive or anxious symptoms. This study examined associations between child sleep at eight years and recurrent pain at nine years along with the moderating role of internalizing symptoms. Families were from a community-based, ongoing longitudinal study (N = 632 children). At eight and nine years, twins (49.2% female, 56.7% non-Latinx European American, 28.8% Latinx) and caregivers participated in assessments focused on child sleep and pain, respectively. Approximately 53% of children had pain in at least one location at least monthly. Internalizing symptoms at age eight were positively associated with number of pain sites at age nine. Lower sleep efficiencies were associated with more pain sites for children with higher levels of internalizing symptoms. Later midpoint times were associated with more pain sites for children with lower levels of internalizing symptoms. Interventions focused on improving children's pain outcomes may consider targeting sleep behaviors and mental health.

The effectiveness of parental distraction during children's acute pain: The moderating effect of socioeconomic status

BACKGROUND

Parental responses to children's pain shape how children interpret and cope with pain symptoms through parental modelling and operant conditioning. Evidence suggests that parental distraction is effective in reducing children's acute pain responses, but findings are inconsistent across pain tolerance, intensity and unpleasantness, and are limited to samples of primarily middle and upper-middle class families. Although socioeconomically disadvantaged families may have fewer psychological resources to cope with pain, no studies have examined whether the utility of parent distraction varies by family socioeconomic status (SES). The current study tested the hypothesis that relations between parental distraction and acute pain responses in children vary by family SES, with children from higher versus lower SES families experiencing more substantial benefits.

METHODS

Children's pain symptoms and parents' use of verbal distraction during a cold pressor task were examined in a community sample of 530 twin children aged 7-12 years old and their primary caregivers.

RESULTS

Parental distraction was positively associated with children's pain tolerance and unrelated to intensity and unpleasantness, but these associations are qualified by significant moderation. In families with higher SES, parental distraction was an effective technique in children's pain management, associated with more pain tolerance and less pain intensity and unpleasantness. However, for families with lower SES, these same benefits were not present.

CONCLUSIONS

Findings suggest that the effectiveness of parental distraction for children's acute pain may depend on family SES.

SIGNIFICANCE

Study findings suggest that the effects of parental distraction on children's responses to an acute pain task vary by family SES. Although parental distraction may be effective for higher SES children, further research is needed to identify whether and why distraction may not be beneficial for lower SES families.

Children's sleep, impulsivity, and anger: shared genetic etiology and implications for developmental psychopathology

BACKGROUND

Prior research has established links between poor sleep and problems in emotion regulation. Impulsivity and anger/frustration are core features of child psychopathology. Further, sleep problems are commonly associated with psychopathology. This study examined shared and unique genetic and environmental influences on sleep, impulsivity, and anger/frustration in the middle childhood period with potential ramifications for psychopathology.

METHODS

Families (29.9% monozygotic, 38.6% same-sex dizygotic, 31.5% opposite-sex dizygotic) from a longitudinal twin study participated (N = 613 twins). Twins (M_age  = 8.37, SD = 0.66; 49% female; 58% non-Latinx European American, 30% Latinx) wore actigraph watches for seven days to assess sleep. Primary caregivers (95.3% mothers) completed standardized questionnaires to assess twins' temperament (impulsivity, anger/frustration).

RESULTS

Univariate ACE twin structural equation models indicated strong genetic influences (76%) on impulsivity, whereas the largest proportion of variance in anger/frustration was attributed to the shared environment (56%). Bivariate model fitting indicated that sleep-impulsivity and sleep-anger/frustration associations in children are genetic; thus, a mutual underlying genetic factor likely contributes to the commonality in these associations.

CONCLUSIONS

Given evidence that sleep problems, impulsivity, and anger/frustration are mechanisms associated with psychopathology, our findings suggest a genetic commonality and the need to focus on shared and unique risk factors when understanding etiology. Early intervention and prevention efforts should target both sleep problems and high levels of impulsivity and anger/frustration in children, which may have implications for later psychopathology.

Epigenetic differences in inflammation genes of monozygotic twins are related to parent-child emotional availability and health

The inflammatory response is an immune defense engaged immediately after injury or infection. Chronic inflammation can be deleterious for various health outcomes and is characterized by high levels of pro-inflammatory markers such as C-reactive protein (CRP), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-α). A large body of research demonstrates these inflammatory markers are responsive to stress and quality of social relationships throughout the lifespan. For example, the quality of the early parental bond predicts various health outcomes and may be driven by changes in immune function. Epigenetic processes, such as DNA methylation, may be one mechanism by which early social experiences shape immune functioning. The present study used a monozygotic twin difference design to assess if mother-reported emotional availability at 1 year and 2.5 years predicted immune gene methylation at 8 years of age. Further, we assessed if inflammation gene methylation was related to general health problems (e.g. infections, allergies, etc.). We found that mother-reported emotional availability at 1 year, but not 2.5 years, was related to methylation of various immune genes in monozygotic twins. Furthermore, twin pairs discordant in health problems have more difference in immune gene methylation compared to twin pairs concordant for health problems, suggesting that methylation of immune genes may have functional consequences for general health. These results suggest that the emotional component of attachment quality during infancy contributes to immune epigenetic profiles in childhood, which may influence general health.