In this paper we provide an integrative synthesis of eight systematic reviews that compromise our systematic review series entitled ‘Population Perspectives on Nurturing Relational Health from Early Life’. We reflect on what we know, what we don’t know, and what we need to know to better safeguard the interpersonal world of the child. Our review series brings forth evidence addressing a fundamental question: How do we create the basis for optimal development of relational skills that enable humans to establish trust, regulate their emotions, engage in exploratory behaviour, communicate effectively, apply introspection, and be more self-efficacious in meeting opportunities and challenges. The collaborating authors provide a unique opportunity to view the current status of this evidence across the bioecology of early human development. They find that our current view of relational health is limited. Much of the extant evidence is concentrated in the microsystem of early life, and it is overly focussed on the mother-infant dyad. Intergenerational findings from longitudinal cohorts point to additional influences on early relational health prior to conception extending back into the life histories of parents; however, these data remain exceptionally rare. There are also immense gaps in cross-cultural applications and extensions that measure, describe and inform the developmental model of relational health along with a glaring and urgent gap in the impacts of the digital social ecology on relational health. Pleasingly, evaluated interventions to promote and influence relational health exist and some are being implemented at scale. However, the outcomes of implementation are almost an after-thought in evaluation designs. We conclude by reflecting on the challenges faced by researchers, governments, policy makers, and agencies in moving relational interventions to scale, and particularly the challenges posed to their onward sustainability, in place, and more universally.

Purpose: This unprecedented longitudinal twin study focused on the arc of language acquisition from first words to adolescence, with data collection at 2, 4, and 6 years of age, reported in four previous studies and now new data at ages 9 and 14 years. Method: The method is a classic twin study design for estimating inherited versus environmental effects. The sample consisted of 1,188 children from 594 twin pairs, ascertained from birth records and followed for studying language and cognitive development. Here, we report language and nonverbal cognitive phenotypes at ages 9 and 14 years. Previous research reports from the sample at younger ages, as well as data from cross-sectional samples in other studies, supported the following generalizations: (a) Twinning effects persisted into adolescence for young children, such that twin children's language milestones were delayed relative to norms for singleton children; (b) twin type, that is, zygosity effects persisted although perhaps reduced with age; (c) gender also played a role for young children with advantages for girls relative to boys; and (d) heritability increased with age. Results: As in earlier studies, twins' standard scores for language were below the expected mean scores of 100 provided by test developers, 97 ( SD = 14) at age 9 years and 95 ( SD = 15) at age 14 years, although the gap relative to age peers is closing. Twin type effects, in which there was a slight disadvantage for monozygotic twins at age 4 years, disappeared at ages 9 and 14 years. Gender was significant at ages 9 and 14 years for vocabulary only but in the opposite direction than expected—with boys outperforming girls; however, this is consistent with singleton longitudinal findings from our lab. Models of heritability included adjustments for gender effects and other covariates. Heritability estimates at ages 9 and 14 years did not significantly differ. The final heritability estimates at age 14 years were .49, .71, and .85 for vocabulary, omnibus language, and nonverbal intelligence quotient (IQ), respectively, suggesting greater environmental effects for vocabulary relative to language and nonverbal IQ. Conclusion: The findings are consistent with previous reports, offering further empirical precision in estimation of the role of genetics in the transition from childhood to adolescence and further support for the need to consider genetics as well as the home environment in the lives of twin children.

BACKGROUND:Adverse childhood experiences (ACEs) are associated with poorer mental health across the life course. However, research examining ACEs during the transition to parenthood has largely focused on mothers, with limited evidence on fathers. OBJECTIVE:To examine associations between cumulative and specific ACEs and mental health and wellbeing among first-time fathers during the first year after their child's birth. PARTICIPANTS AND SETTING:Participants were 718 first-time fathers (Mage = 34.69 years; SD = 6.98 years) drawn from the Ten to Men Study, a population-representative cohort of Australian men. METHODS:Fathers retrospectively reported ACEs using the ACE-10 questionnaire and completed measures of depression (PHQ-9), anxiety (GAD-7), problematic alcohol use (AUDIT), and wellbeing (Personal Wellbeing Index). Generalised linear models estimated associations between exposure to ACEs and outcomes, adjusting for study wave and demographic covariates. Models also examined independent associations between specific ACE types and outcome measures. RESULTS:Compared with fathers reporting no ACEs, those reporting 2-3 ACEs showed higher depressive and anxiety symptoms and lower wellbeing, with stronger effects observed for those reporting ≥4 ACEs (all p < .05). Cumulative ACE exposure was not significantly associated with problematic alcohol use. Childhood sexual abuse, feeling unloved, and verbal abuse were independently associated with higher depression and anxiety and poorer wellbeing, while household substance use predicted higher problematic alcohol use. CONCLUSIONS:ACEs are associated with poorer mental health and wellbeing among first-time fathers. Identifying fathers with childhood adversity histories may help inform early prevention and intervention efforts during the transition to parenthood.

This paper provides the conceptual framework for a new review series that bring together the global literature on population approaches to nurturing relational health across the first three years of life. Early relational health is defined as ‘the everyday interactions that happen between children and their carers across the many settings in which they live and grow … that meet universal needs for food and shelter, for safety, and for a sense of belonging, worth, identity and place that collectively establish secure foundations for lifespan health and development'. The first four reviews describe (1) the relational ecology of early childhood, (2) associations with early brain development, (3) associations with relational outcomes beyond early childhood, and (4) evidence-based interventions for nurturing relational health within universal, population-based, settings (e.g., maternal-child health). The next four reviews tackle the deeper intergenerational question of what it means to raise children and young people in ways that also set developmental conditions for future roles as parents by describing (5) Australian Aboriginal ways of nurturing relationally healthy children and young people, (6) findings from intergenerational cohort studies, (7) population based interventions for nurturing relational health from childhood to parenthood (e.g., schools and communities), and (8) approaches to implementing evidence-based interventions in ways that ensure sustainability. An additional technical paper describes the development and testing of a new AI platform (LitQuest) that was purpose built to expedite title and abstract screening for the review series. Findings from the complete series are synthesised in a final paper that identifies critical gaps in the evidence base and provides recommendations for future research to advance population-level approaches to nurturing relational health from the earliest years of life.

As families increase their use of mobile touch screen devices (smartphones and tablet computers), there is potential for this use to influence parent-child interactions required to form a secure attachment during infancy, and thus future child developmental outcomes. Thirty families of infants (aged 9-15 months) were interviewed to explore how parents and infants use these devices, and how device use influenced parents' thoughts, feelings and behaviours towards their infant and other family interactions. Two-thirds of infants were routinely involved in family video calls and one-third used devices for other purposes. Parent and/or child device use served to both enhance connection and increase distraction between parents and infants and between other family members. Mechanisms for these influences are discussed. The findings highlight a new opportunity for how hardware and software should be designed and used to maximise benefits and reduce detriments of device use to optimise parent-infant attachment and child development.

BACKGROUND:Digital technology is ubiquitous in the lives of many children and parents. To better understand any influence of technology use by infants, and mothers, on child development, technology use should be considered within the broader family system context in which children develop. This study aimed to investigate associations between infant and maternal technology use and infant 12-month development, taking into consideration other family factors. METHODS:This cross-sectional study used data from ORIGINS participants, collected at 12-months of age: maternal and child technology use (TechU-Q), sociodemographic factors (e.g. child sex, household income), parental mental health (DASS-21), and child development (Ages and Stages Questionnaire). Linear regression was used for analyses. RESULTS:When family factors were considered, higher infant mobile touchscreen device (MTSD) use was associated with poorer infant development for gross motor, problem-solving, and total ASQ-3 scores. In contrast there were no associations between infant television (TV) watching or maternal technology use and total ASQ-3 scores. Higher maternal technology use was associated with higher infant technology use. Poorer maternal and paternal mental health were associated with poorer infant development. Poorer maternal mental health was also associated with higher infant TV watching and higher maternal MTSD use. CONCLUSION:There is a complex relationship between technology use, parental mental health and other family factors that together influence infant development. To improve infant development outcomes, less focus should be on infant or maternal technology use, and more on supporting the family as a whole, and parental mental health in particular.

Children and adolescents spend more than one-third of their time sleeping. Yet, we know little about the causal impact of sleeping on their development. This paper is the first to exploit variation in local daily daylight duration measured on pre-determined diary dates across the same individuals through time as an instrument in an individual fixed effects regression model to draw causal estimates of sleep duration on a comprehensive set of child development indicators. Applying this model to about 50 thousand time use diaries from two cohorts of Australian children spanning over 16 years, we first document that children sleep substantially less on days with longer daylight duration. Our results show that sleeping longer improves selected general developmental, behavioural and health outcomes in children and adolescents. By contrast, sleeping more statistically significantly increases the BMI scores, mainly by increasing the risk of being overweight. Moreover, while the impact of sleep duration on general and behavioural outcomes is more pronounced for females or older individuals, the effect on BMI is largely driven by males. The results indicate a null or relatively small positive impact of sleeping longer on cognitive skills.

Understanding the drivers of student dropout from higher education has been a policy concern for several decades. However, the contributing role of certain factors—including student mental health—remains poorly understood. Furthermore, existing studies linking student mental health and university dropout are limited in both methodology and scope—for example, they often rely on small and/or non-representative samples or subjective measures, and focus almost exclusively on main effects. This paper overcomes many of these shortcomings by leveraging unique linked administrative data on the full population of domestic students commencing undergraduate studies at Australian universities between 2012 and 2015 ( n = 652,139). Using these data, we document that approximately 15% of students drop out of university within their first academic year. Critically, students receiving treatment for mental health problems are 4.3 (adjusted) to 8.3 (unadjusted) percentage points more likely to drop out of higher education. This association remains in the presence of an encompassing set of potential confounds, and is remarkably uniform across segments of the student population determined by individual, family, and programme characteristics. Altogether, our findings call for increased policy efforts to improve student mental health and to buffer against its deleterious effects on retention.

This paper provides the first causal evidence on the impact of retirement on housing choices. Our empirical strategy exploits the discontinuity in the eligibility ages for state pension as an instrument for the endogenous retirement decision and controls for time-invariant individual characteristics. The results show that retirement leads to a statistically significant and sizable increase in the probability of making a residential move or the likelihood of becoming outright homeowners. We also find that individuals downsize both physically and financially and tend to move to better neighbourhoods or closer to the coast upon retirement. We additionally discover that some housing adjustments take place up to 6 years before retirement. Moreover, our results reveal significant heterogeneity in the retirement impact by gender, marital status, education, housing tenue, income and wealth. Within couple households, housing mobility choices are primarily influenced by the wife’s retirement while housing downsizing decisions are only affected by the husband’s retirement. The results suggest that failing to address the endogeneity of retirement often under-states the retirement impact on such housing arrangements.

This study explores the allocation of time, particularly to sleep, among children and adolescents in response to daily daylight variation. Utilising a dataset of over 50,000 time-use diaries from two Australian cohorts spanning 16 years and employing an individual fixed effects estimator, we uncover a substantial causal impact of daily daylight duration on sleep patterns. Our findings reveal that days with longer daylight hours are associated with a decrease in total sleep duration, primarily driven by a later sleep onset time. Additionally, longer daylight hours correspond to reduced time spent on personal care and media activities, with increased dedication to school and physical activities. Furthermore, we identify socio-demographic factors moderating these effects, such as older age and weekend days exerting a stronger influence on sleep duration, while females and children of unemployed mothers exhibit a subtle impact. These insights contribute to our understanding of how environmental factors shape daily routines and offer implications for designing schedules that promote positive developmental outcomes in young individuals.

Purpose Despite the volume of accumulating knowledge from prospective Aboriginal cohort studies, longitudinal data describing developmental trajectories in health and well-being is limited. The linkage of child and carer cohorts from a historical cross-sectional survey with longitudinal health-service and social-service administrative data has created a unique and powerful data resource that underpins the Western Australian Aboriginal Child Health Survey (WAACHS) linked data study. This study aims to provide evidence-based information to Aboriginal communities across Western Australia, governments and non-government agencies on the heterogeneous life trajectories of Aboriginal children and families.Participants This study comprises data from a historical cross-sectional household study of 5289 Aboriginal children from the WAACHS (2000-2002) alongside their primary (N=2113) and other (N=1040) carers, and other householders. WAACHS data were linked with Western Australia (WA) government administrative datasets up to 2020 including health, education, child protection, police and justice system contacts. The study also includes two non-Aboriginal cohorts from WA, linked with the same administrative data sources allowing comparisons of outcomes across cohorts in addition to between-group comparisons within the Aboriginal population.Findings to date Linked data coverage rates are presented for all WAACHS participants. Child health outcomes for the WAACHS children (Cohort 1) are described from birth into adulthood along with other outcomes including child protection and juvenile justice involvement.Future plans Analysis of data from both the child and carer cohorts will seek to understand the contribution of individual, family (intergenerational) and community-level influences on Aboriginal children's developmental and health pathways, identify key developmental transitions or turning points where interventions may be most effective in improving outcomes, and compare service pathways for Aboriginal and non-Aboriginal children. All research is guided by Aboriginal governance processes and study outputs will be produced with Aboriginal leadership to guide culturally appropriate policy and practice for improving health, education and social outcomes.

The media plays a powerful role in shaping health-related attitudes and behaviours. We investigated media reports about children's independent mobility (CIM) and associations with parental attitudes towards CIM. CIM-related media reports (newspaper, online, television) during a 3-month period were extracted from two databases. Concurrent parental attitudes were collected via telephone interview from 1779 parents of children aged 9-15 years. Media reports were overwhelmingly negative: 94% mentioned only risks and 6% mentioned benefits. There was no association between media reports and parental attitudes. Parental CIM attitudes are often complex and pervasive and may not be shifted by media coverage alone.

The reciprocal relationship between psychiatric and substance use disorders is well-known, yet it remains largely unknown whether mental health morbidity causally leads to addictive behaviours. This paper utilises a fixed effects instrumental variables model, which is identified by time-varying sources of plausibly exogenous variations in mental health, and a nationally representative panel dataset from Australia to present robust evidence on the causal impact of mental distress on cigarette smoking and alcohol drinking behaviours. We find that mental distress significantly increases the prevalence and intensity of either cigarette or alcohol consumption. Further analysis reveals that mental distress also substantially increases household monetary expenditures on either tobacco or alcohol. The impact is greater for lower educated individuals or children of smokers, and is slightly higher for males. Our findings highlight the importance of mental health screening and treatment programs, especially among lower educated individuals or children of smokers, to assist in the prevention of addictive activities.

PURPOSEPrevious studies showed that unfavourable weather conditions discourage physical activity. However, it remains unclear whether unfavourable weather conditions have a differential impact on physical activity in children compared with adults. We aim to explore the differential impact of weather on time allocation to physical activity and sleep by children and their parents.METHODWe use nationally representative data with time use indicators objectively measured on multiple occasions for >1100 Australian pairs of 12-13-year-old children and their middle-aged parents, coupled with daily meteorological data. We employ an individual fixed effects regression model to estimate the causal impact of weather.RESULTSWe find that unfavourable weather conditions, as measured by cold or hot temperatures or rain, cause children to reduce moderate- and vigorous-intensity physical activity time and increase sedentary time. However, such weather conditions have little impact on children's sleep time or the time allocation of their parents. We also find substantial differential weather impact, especially on children's time allocation, by weekdays/weekends and parental employment status, suggesting that these factors may contribute to explaining the differential weather impact that we observed. Our results additionally provide evidence of adaptation, as temperature appears to have a more pronounced impact on time allocation in colder months and colder regions.CONCLUSIONOur finding of a negative impact of unfavourable weather conditions on the time allocated to physical activity by children indicates a need to design policies to encourage them to be more physically active on days with unfavourable weather conditions and hence improve child health and wellbeing. Evidence of a more pronounced and negative impact on the time allocated to physical activity by children than their parents suggests that extreme weather conditions, including those associated with climate change, could make children vulnerable to reduced physical activity.

Using over 50 thousand time-use diaries from two cohorts of children, we document significant gender differences in time allocation in the first 16 years in life. Relative to males, females spend more time on personal care, chores and educational activities and less time on physical and media related activities. These gender gaps in time allocation appear at very young ages and widen overtime. We provide novel evidence that gender differentials in time investment are quantitatively important in explaining a female advantage in most cognitive and non-cognitive skills. Moreover, gender disparity in educational time outside of school is the most important factor contributing to gender test score gaps and its contribution is more pronounced for higher performing students. By contrast, gender differences in media time are the main factor explaining gender gaps in non-cognitive skills. As children age, gender differences in time allocation play an increasing role in explaining gender gaps in both cognitive and non-cognitive skills.

This study investigated patterns of universal health and education service use from birth through Kindergarten (age 4 years) and estimated associations between cumulative risk and service use patterns, and between service use patterns and children's developmental vulnerability in the Preparatory Year (age 5 years). The study used population-wide linkage of health and education administrative data records for 5168 children who had a 2018 AEDC instrument collected in Tasmania and were born in Tasmania (2011–2013). Latent class analysis (LCA) identified three service use patterns: Regular (72.2 per cent of children; reference group), Low (15.6 per cent of children) and High service use (12.2 per cent of children). The patterns of Regular, Low and High service use were consistent across health and education services used at different ages and stages of child development. Membership of the Low and High service use groups was associated with higher cumulative risk and increased odds of developmental vulnerability, relative to the Regular service use group. This population-wide view of universal service use can be used by the health and education sectors to explore ways in which their specialist expertise, resources and referral processes can be further integrated within and across services to meet the developmental needs of children and families.

In this paper, we aim to contribute to the understanding of the multidimensional nature of school readiness. In a sample of over 4,000 Australian children in their first year of school, we used latent class analysis to examine patterns of school readiness based on child, family, school and community characteristics, and examine the relationship between these patterns of school readiness and subsequent outcomes (reading comprehension, school absence and emotional and behavioural difficulties). We identified four distinct groups: a Developmentally Enabled group (70 per cent of children), a Parenting Risk group (16 per cent of children), an Emotionally Immature Risk group (7 per cent of children) and a Language and Developmental Risks group (7 per cent of children). The four profiles showed differential patterns of association with low reading comprehension and emotional and behavioural difficulties at age 8, but no association with school absence. The study highlights the importance of family, school and community factors when considering school readiness.

The potential for human-computer interaction to have a substantial impact on adults is well documented. However, its potential importance prior to birth has rarely been reported. Parental use of smartphones and tablet computers could influence the relationship between parent and baby during pregnancy (prenatal attachment) and thus child development. Twenty-seven families were interviewed to explore how parents used these devices during pregnancy, and how device use influenced parents' thoughts, feelings and behaviours towards their baby while in utero. All used devices for a variety of purposes, and all described good levels of prenatal attachment. Parents described both disrupted and enhanced connectedness as a result of device use, and increased parental stress. The findings highlight a new opportunity for how device design and use guidelines could support families to maximise benefits and reduce detriments of device use to optimise prenatal attachment, and thus future parent-child attachment and child development. Practitioner summary: Many parents regularly use smartphones and tablet computers while pregnant. This qualitative study found that how devices were used either enhanced or disrupted feelings of prenatal attachment. Practitioners should be aware of potential beneficial and detrimental impacts of device use during pregnancy given implications for future attachment and child development.

AbstractIn this chapter we provide a brief summary of the key themes of the book, identify emerging directions and challenges in life course theory and data designs and highlight some policy challenges for researchers going forward.