Summary Background First Nations children are over-represented in child protection systems in Australia and other colonised countries. Here, we apply a prevention and equity lens to the use of child protection data, to inform early opportunities to support Aboriginal children and families at risk of escalating child protection contact, from pregnancy to adolescence. Methods We followed 15 whole-population cohorts (born 2006-2020) of Aboriginal (n=119,716) and non-Aboriginal (n=1,456,698) children in New South Wales (NSW), Australia, to December 2021, using birth and child protection datasets linked for the NSW Child E-Cohort. In each Aboriginal and non-Aboriginal cohort born 2006 to 2020, we calculated the cumulative incidence (risk) of first-time child protection contacts from the prenatal period up to age 15 years: reports to child protection, screened in reports, investigations, child protection- defined substantiations (of actual harm or risk of significant harm assessed in the investigation), and OOHC placements. Risk differences and relative risks were also calculated. Findings By birth, 10-15% of Aboriginal children born 2006-2020 had a first report to child protection, with 48-54% by age 5y (2006-2016 births), and 74% by age 15y (2006 births), with similar risks of screened-in reports (e.g. 68% by age 15y). The risk of first-time substantiation was 1- 5% of Aboriginal children by birth, 17-20% by 5y, and 32% by 15y, with higher risks in more contemporary cohorts. By age 1y, 3-4% of Aboriginal children born 2006-2020 had a first OOHC placement, with 7-9% by 5y, and 14% by 15y. The risk differences between Aboriginal and non-Aboriginal children were 23 and 3 percentage points for reports and OOHC by age 1y (2020 births), respectively, increasing as children age. Interpretation Despite extensive inquiries, calls for prevention and Closing the Gap targets, our study shows the lifetime risk of child protection involvement for Aboriginal families has not improved and inequities persist. These findings support the call for Aboriginal-led approaches and greater investment in early supports for First Nations children and families. Research in Context Evidence before this study We searched PubMed and Medline for studies on the lifetime risk of child protection contacts among First Nations child populations, published January 2005 to May 2025. Thirteen studies reported various child protection contacts, from the perinatal period through childhood, among birth or synthetic cohorts of First Nations children, born between 1990 and 2018, created from population data sources in jurisdictions in Australia (n=5), the United States(US) (n=6), and Aotearoa/New Zealand (NZ) (n=2) (Table E1). The most recently published study included First Nations children born 2000 to 2013 in Western Australia, which quantified the risk of reports, investigations, substantiations and removals into OOHC, from age 1 to 16 years. By age 1, 12% were reported and 3% were removed into OOHC. By age 16, 52% were reported, and 14% were removed into OOHC. Prior studies of birth or synthetic cohorts of First Nations children born 1990-2018, in the USA, NZ, and South Australia showed similar results. By age 5 years, 16% to 54% for reports, 20% for investigations, 7% to 11% for substantiations and 8% for removals into OOHC. Among the five studies with cohorts followed to 18 years, 42% were reported, 28% to 50% were investigated, 9% to 27% were substantiated, 7% to 16% were removed into OOHC and 0.8% to 3.8% had termination of parental rights. Added value of this study This is the largest and most contemporary study to quantify the lifetime risk of child protection contact among whole-populations of First Nations children internationally. Among 15 consecutive whole-population cohorts of First Nations children in New South Wales (NSW), Australia, born 2006 to 2020, we reported—for the first time—the full spectrum of child protection contacts, from the prenatal period. By birth, 16% were reported to child protection, 14% were investigated and 5% were substantiated in the most contemporary cohort born 2020. By age 1 year, 2.8% were removed into OOHC. In the oldest cohort born 2006, 74% were reported and 14.4% removed into OOHC by age 15 years. We also reveal the magnitude of the inequity in child protection contacts between First Nations and non-Indigenous children across the lifecourse. For example, among 2006 births, the risk of first-time reports to child protection for Aboriginal and non-Aboriginal children, respectively, was 10.5% versus 1.5% by birth (risk difference (RD), 9 percentage points; risk ratio (RR), 7.0), 53% vs 16% by age five (RD, 38pp; RR, 3.4) and 74% vs 33% by age 15 (RD, 41pp; RR 2.2). Implications of all the available evidence This study unequivocally shows that the lifetime risk of child protection involvement in the lives of First Nations families has not reduced in more contemporary whole-population cohorts and that inequities persist. This is consistent with evidence from prior studies internationally. It is critical that First Nations-led responses and investment in early family supports must be at the centre of system reform to realise the long-called-for shift toward prevention and to re-dress the pervasive inequities experienced by First Nations children and families in colonised countries such as Australia.

Background First Nations children are over-represented in child protection systems in Australia and other colonised countries. Here, we apply a prevention and equity lens to the use of child protection data, to inform early opportunities to support Aboriginal children and families at risk of escalating child protection contact, from pregnancy to adolescence. Methods We followed 15 whole-population cohorts (born 2006-2020) of Aboriginal (n=119,716) and non-Aboriginal (n=1,456,698) children in New South Wales (NSW), Australia, to December 2021, using birth and child protection datasets linked for the NSW Child E-Cohort. In each Aboriginal and non-Aboriginal cohort (2006-2020), we calculated the cumulative incidence (risk) of first-time child protection contacts from the prenatal period up to age 15 years: child concern reports, screened in reports, investigations, child protection-defined substantiations, and OOHC placements. Risk differences and relative risks were also calculated. Findings By birth, 10-15% of Aboriginal children born 2006-2020 had a first report to child protection, with 48-54% by age 5y (2006-2016 births), and 74% by age 15y (2006 births), with similar risks of screened-in reports (e.g. 68% by age 15y). The risk of first-time substantiation was 1-5% of Aboriginal children by birth, 17-20% by 5y, and 32% by 15y, with higher risks in more contemporary cohorts. By age 1y, 3-4% of Aboriginal children born 2006-2020 had a first OOHC placement, with 7-9% by 5y, and 14% by 15y. The risk differences between Aboriginal and non-Aboriginal children were 23 and 3 percentage points for reports and OOHC by age 1y (2020 births), respectively, increasing as children age. Interpretation Despite extensive inquiries, calls for prevention and Closing the Gap targets, our study shows the lifetime risk of child protection involvement for Aboriginal families has not improved and inequities persist. These findings support the call for Aboriginal‑led approaches and greater investment in early supports for First Nations children and families. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement The NSW Child E-Cohort Project has receiving funding support from a National Health and Medical Research Council (NHMRC) Clinical Trials and Cohort Studies Grant (1187489) and a UNSW Medicine Neuroscience, Mental Health and Addictions Theme and SPHERE Clinical Academic Group seed funding grant. The Bring Them Home, Keep Them Home Project was funded by an ARC Discovery Indigenous grant (194187). This study also received funding through a pilot grant from the Research Excellence in Aboriginal Child and Adolescent Health (REACH) Centre for Research Excellence (1135273). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was approved by the NSW Population and Health Services Research Ethics Committee (2020/ETH01265), the University of NSW HREC (2020/ETH01265), and the Aboriginal Health and Medical Research Council (AH&MRC) of NSW Ethics Committee (1688/20) I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present work are contained in the manuscript and supplemental tables

BACKGROUND AND OBJECTIVES:Children with prenatal substance exposure are at high risk of child protection involvement during infancy. We quantified the risk and timing of child protection system involvement until age 12 years among children with and without prenatal substance exposure. METHODS:A whole-population birth cohort (2007-2018) was assembled from data linked for the New South Wales Child E-Cohort, Australia. The prenatal substance exposure population included children with records indicating prenatal substance exposure in hospital, emergency, mental health outpatient, opioid treatment, and/or child protection reports data. We estimated the risk of child protection responses (screened-in reports, investigations, substantiations, and out-of-home care [OOHC]), and child maltreatment types. RESULTS:1 161 876 children (17 976 with prenatal substance exposure) and 717 063 mothers were included. By age 1 year, 75% of the prenatal substance exposure population born in 2018 had ≥1 screened-in report, 34% ≥1 substantiation, and 20% ≥1 OOHC placement, compared with 4%, 0.8%, and 0.2% of all other children, respectively. By age 12, 90% of the prenatal substance exposure population born in 2007 had ≥1 screened-in report, 61% ≥1 substantiation, and 39% ≥1 OOHC placement, compared with 18%, 5%, and 1% of all other children, respectively. One-half of the prenatal substance exposure population had neglect recorded by age 12. Health and socioeconomic disadvantage were more common among the prenatal substance exposure population. CONCLUSION:Children with prenatal substance exposure experienced high child protection involvement early in life. Child protection reports represent an opportunity to mobilize nonstigmatizing substance use in pregnancy and antenatal care to prevent escalating child protection interventions.

OBJECTIVES:To estimate the prevalence of maternal substance use problems during the first 1000 days of children's lives, to inform planning and resourcing of antenatal screening and substance use in pregnancy services, alongside antenatal and postnatal health, parenting and social support services for pregnant women/new mothers and their babies. METHOD:This whole-population cohort was assembled from birth registration, perinatal and hospital data for children born 2008-2017, and their mothers, using data linked for the New South Wales (NSW) Child E-Cohort Project. The primary outcome was maternal substance use conditions and treatment recorded in six health, death and child protection data sources from the child's conception to age 2 years (the first 1000 days), including illicit substances, alcohol, opioid-agonist treatment and misuse of psychoactive medicines or substances. RESULTS:Of 970 470 children born to 625 856 mothers, 3.4% (N=32 647) had ≥1 maternal substance use problem records in the first 1000 days, including alcohol use (N=13 637; 1.4%) and other drug use (N=23 485; 2.4%). Maternal substance use problems were recorded during the pregnancy period for 1.4% of children, and from 28 to 1000 days postbirth for 2.7% of children. Outcome ascertainment was highest from child protection records (N=26 045), followed by mother's (N=10 793) then children's hospital records (N=3827). Child protection records more than doubled the prevalence of health and death records alone (1.4%). Social and health disadvantage was more common among children with maternal substance use problems. CONCLUSIONS:During the first 1000 days of life, 3.4% of NSW children had ≥1 maternal substance use problem recorded in health, child protection and death data sources. Child protection data enhance public health intelligence on the burden of maternal substance use problems among whole child populations. Near universal health system contact during pregnancy and birth is an opportunity to initiate early support for maternal substance use and co-occurring health and social disadvantage, to promote child health and development.

This article investigates risk of Youth Justice (YJ) supervision by age 18, among children who had experienced Out-Of-Home Care (OOHC) before age 10. Data were drawn from the Better Evidence Better Outcomes Linked Data platform. Children born 1991-1998 who experienced at least one placement in OOHC before age 10 (N = 2,832) were followed to age 18 for YJ supervision. Logistic regression models including child and maternal sociodemographic and perinatal characteristics and child protection characteristics were used to predict the probability of (a) any YJ supervision; (b) any custodial YJ supervision by age 18. Of children in OOHC before age 10, 13.5% (n = 381) experienced any YJ supervision by age 18, and 10.6% (n = 300) experienced custodial YJ supervision. Using all 42 predictors, model discrimination (Area Under the Receiver Operator Characteristic Curve (AUROC) and Area Under the Precision Recall Curve (AUPRC)) was similar to 0.8 and similar to 0.4, respectively, for both outcomes. We used the top 30% of the predicted probabilities to create a '' high '' risk threshold. At this high-risk threshold, sensitivity was 69.8% and 75.3%, respectively; specificity was 76.5% and 75.5%; and the positive predictive value was 32.3% and 26.8%. These risk prediction models have reasonable discrimination to identify children in OOHC who are at higher risk of transitioning into YJ, and are technically feasible. However, predicting risk implies providing opportunities for early supports that may prevent transitions from OOHC to YJ. There are ethical and practical considerations to using prediction models in this population.

Objectives To understand how we can better initiate and run international collaborations to deliver tangible and impactful findings using population-wide linked health and education data. Approach Representatives from 14 countries (America, Australia, Canada, Chile, Denmark, England, Finland, Germany, New Zealand, Northern Ireland, Norway, Scotland, Sweden, Wales) summarised the potential for research using their linked administrative health and education data. The scope for collaboration and comparison of research findings across countries was explored. Results Several substantive research themes emerged, including the quantifying of differences in educational outcomes by health conditions and other early life factors, using health data to better identify and explore the special educational needs identified in educational records, using linked health and education data to identify and explore reasons for absenteeism from school. Conclusions The workshop showcased the primary themes for research and the data assets available within each country for comparative work. Further work is required to more robustly document the available detail within these datasets, collaboratively develop protocol templates for comparative studies, and develop pilot, proof of concept, studies.

This was made longer in response to request from reviewers. If a longer abstract cannot be accommodated, a shorter abstract is pasted here: Children who have 'early contact' with youth justice (YJ) are a group of significant policy interest. Understanding circumstances which precede or co-occur with YJ contact can support the development of preventive investments and inform debates about systemic reform, such as 'raise the age'. Using whole-of-population administrative data from the SA Better Evidence Better Outcomes Linked Data (BEBOLD) platform, we examine differences between children who have early (i.e. between the ages of 10 and 13 years) versus late (i.e. at age 14 or older) YJ contact, relative to the general population. Children born 1991-2022 were followed from birth to age 18 (N = 249,995). Compared to the late-contact group, children with early contact experienced more serious YJ contact (91% versus 59% experienced custody); were more disadvantaged at birth (e.g. 66% versus 45% born into jobless families); had more serious child protection contact by age 10 (26% versus 12% experienced out-of-home care); and experienced mental health-related hospitalisations from ages 12-18 (43% versus 34%). Relative to the general population, both groups were characterised by significant social and economic disadvantage, child protection contact and mental health challenges. The need for investment in early prevention to divert children from the justice system is clear.

In Australia, as elsewhere, there is consensus that new and more effective ways of responding to young people who commit crimes need to be identified and, when available, implemented and evaluated. In this paper we review youth justice legislation across each Australian jurisdiction and consider how it provides the mandate for service delivery. We contextualise this with an account of historical variations in how the seemingly competing goals of welfare and justice have been balanced. This is followed by an overview of contemporary understandings of child development and human rights which are increasingly recognised as both relevant and important to the way in which the community works with justice-involved children and young people. The analysis illustrates how youth justice agencies are still expected to achieve multiple and, at times, conflicting legislated objectives which results in a lack of coherence in policy and practice. This serves only to limit effectiveness. We conclude that legislative reform will be necessary to realise any new vision for youth justice, especially if one of the overarching purposes is to protect vulnerable children.

IssuesAlthough maternal substance use is a known risk factor for child maltreatment, evidence on the scale of substance use is needed to inform prevention responses. This systematic review synthesised prevalence estimates of maternal substance use during pregnancy and early life among children at risk of maltreatment. Ovid, Pubmed, CINAHL, PsychInfo and ProQuest databases were searched. We included observational studies that sampled children at risk of maltreatment in high-income countries and reported information on maternal substance use during pregnancy and/or the child's first year of life. We extracted study characteristics and data to calculate prevalence, assessed risk of bias and conducted a narrative synthesis; there were insufficient comparable populations or outcomes to quantitatively synthesise results.Key FindingsThirty five of 14,084 titles were included. Fifteen studies had adequately sized and representative samples to estimate prevalence. Maternal substance use prevalence ranged from 2.4% to 40.6%. Maternal substance use was highest among infants referred to child protection at birth (40.6%) and children in out-of-home care (10.4% to 37.2%). Prevalence was higher when studies defined substance use more broadly and when maternal substance use was ascertained from both child and mother records.ImplicationsSupportive, coordinated responses to maternal substance use are needed from health and child protection services, spanning alcohol and other drug treatment, antenatal and postnatal care.ConclusionsPrenatal and early life maternal substance use is common among child maltreatment populations, particularly among younger children and those with more serious maltreatment.

Objective Youth criminal justice systems are under growing pressure to reduce re-offending behavior and to support young people’s health and developmental needs. This systematic review and meta-analysis sought to synthesise evidence for 2 prominent community-based interventions for delinquent and antisocial behavior, namely, multisystemic therapy (MST) and functional family therapy (FFT). Method We searched Medline, PsycInfo, Scopus, Web of Science, and Social Services Abstracts for randomized controlled trials (RCTs) and quasi-experimental studies evaluating MST/FFT. Included studies involved participants aged under 18 years; included interventions targeted delinquent/antisocial behavior, but not maltreatment. We estimated effect sizes for 6 primary outcomes, synthesising RCTs comparing MST/FFT to usual care using correlated hierarchical effects meta-analysis. We assessed risk of bias and evidence strength using best-practice tools. Given the additional resources needed to implement MST/FFT, we rated evidence strength against a minimum clinically important difference rather than a null effect. This study is registered with PROSPERO, CRD42021279736. Results We included 35 studies for MST (16 RCTs meta-analyzed comprising 4,095 participants, 26% female) and 19 studies for FFT (7 RCTs meta-analyzed comprising 1,471 participants, 22% female). MST had a likely clinically important effect on time in out-of-home care, but no clinically important effects on other primary outcomes (delinquency, new offenses/convictions, placement in out-of-home care, substance use), with low-to-moderate evidence strength. FFT demonstrated possible clinically important effects for the number of new offenses/convictions, time in out-of-home care, and substance use, but evidence strength was low. Conclusion Contrary to reports in some evidence clearinghouses indicating that MST/FFT are supported by the highest level of evidence strength, there is limited evidence that these interventions are superior to usual care in reducing delinquent and antisocial behavior in adolescence. These findings should be viewed in the context of important methodological differences with prior reviews, including the rating of evidence strength against a minimum clinically important difference. Study preregistration information The effect of Multi-Systemic Therapy and Functional Family Therapy in addressing child and adolescent delinquent and/or antisocial behavior and childhood maltreatment; https://www.crd.york.ac.uk/; 279736.

ObjectiveTo illustrate how whole-population linked data can be used to understand a system perspective of client complexity, and build robust evidence of Family by Family program impact. MethodsFamily by Family program (the program) participant data were linked into the Better Evidence Better Outcomes Linked Data (BEBOLD) Platform. BEBOLD is a whole-of-population linked de-identified administrative data platform for all South Australian children born 1991 onwards (n~500,000), as well as their parents including data spanning health, education, and social services. We descriptively analysed parental child protection history, emergency department presentations, hospitalisations, homelessness and justice system contact in the 24 months prior to and post program commencement. We emulate a trial using the ‘target trial’ causal inference framework to evaluate the program effect on a range of child outcomes using targeted maximum likelihood with a set of over 20 confounders. Results There were 361 families and 841 children in the program included in analysis. Selected results follow: Prior to the program, 35.8% of children were in a family where at least one parent had their own child protection history and 8% had a parent who experienced out-of-home care. Nearly 40% of children had at least one parent with a mental health related emergency department and/or hospitalisation, while 22% of children were in a family with specialist homelessness service contact. Program impact results will be presented at the conference. ConclusionThis research-practice partnership illustrates how bringing together program and linked-administrative data generates new evidence about client complexity and program impact.

Abstract Objectives: To estimate the prevalence of maternal substance use during the first 1000 days of children's lives, to inform planning and resourcing of antenatal screening and substance use in pregnancy services, alongside antenatal and postnatal health, parenting and social support services for pregnant women/new mothers and their babies. Method: This whole-population cohort was assembled from birth registration, perinatal, and hospital data for children born 2008-2017, and their mothers, using data linked for the New South Wales (NSW) Child E-Cohort Project. The primary outcome was maternal substance use and treatment recorded in six health, death, and child protection data sources from the child's conception to age 2-years (the first 1000 days), including illicit substances, alcohol, opioid-agonist treatment, and misuse of psychoactive medicines or substances. Results: Of 970,470 children born to 625,856 mothers, 3.4% (N=32,647) had ≥1 maternal substance use records in the first 1000 days, including alcohol use (N=13,647; 1.4%) and other drug use (N=23,485; 2.4%). Maternal substance use was recorded during the pregnancy period for 1.2% of children, and from 28-1000 days post-birth for 2.4% of children. Outcome ascertainment was highest from child protection records (N=26,045), followed by mother's (N=12,956) then children's hospital records (N=3,826). Child protection records more than doubled the prevalence from health and death records alone (1.4%). Social and health disadvantage was more common among children with maternal substance use. Conclusion: During the first 1000 days of life, 3.4% of NSW children had ≥1 maternal substance use record in health, child protection and death data sources. Child protection data enhances public health intelligence on the burden of maternal substance use among whole-populations of children. Near universal health system contact during pregnancy and birth is an opportunity to initiate early support for maternal substance use and co-occurring health and social disadvantage, to promote child health and development. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement Madeleine Powell was supported by an Australian Government Research Training Program (RTP) Scholarship via the University of New South Wales (UNSW), Sydney, Australia, and a Higher Degree Research scholarship from the National Drug and Alcohol Research Centre (NDARC), UNSW. This work was supported by an NHMRC Clinical Trials and Cohort Studies grant (1187489) awarded to K Falster, R Pilkington, and J Lynch. R Pilkington and Tasnia Ahmed were supported by funds from the NHMRC Clinical Trials and Cohort Studies grant. Rhiannon Pilkington and Tasnia Ahmed were supported by an Australian National Health and Medical Research Council (NHMRC) Clinical Trials and Cohort Studies grant (#1187489). Alys Havard is supported by an NHMRC Ideas grant (#2010778) and the National Drug and Alcohol Research Centre, which is supported by funding from the Australian Government Department of Health under the Drug and Alcohol Program. The other authors received no additional funding. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics approval: This study was approved by the NSW Population and Health Services Research Ethics Committee (2020/ETH01265), the University of NSW HREC (2020/ETH01265), the Aboriginal Health and Medical Research Council (AH&MRC) of NSW Ethics Committee (1688/20), the NSW Corrective Services Ethics Committee (D20/0886760). The CHeReL operate under strict data security protocols and implements high level physical security measures. Their security protocols are in accordance with the Australian Government Protective Security Policy Framework, the Population Health Research Network Information Governance Framework, and the NHMRC Code for Responsible Conduct of Research. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data availability statement: No data are available because Australian privacy laws prohibit us from making the individual-level de-identified data publicly available. The data used for this study were provided by several Australian State and Commonwealth government agencies under agreements with the researchers led by KF (in NSW) and JWL (in SA), the NSW Centre for Health Record Linkage (CHeReL) and SANT Datalink, following approval from multiple ethics committees and data custodians. Data are only able to be accessed by researchers who are approved users by the relevant ethics committees and data custodians. Data can be accessed through an application and approval process administered by the independent data linkage authorities, NSW CHeReL or SANT Datalink.

IntroductionTo prevent abuse, neglect and poor outcomes for children and families, including child protection intervention, maltreatment, and removals, it is critical to understand the scale and timing of child protection system contacts to identify opportunities for early prevention. Objectives and ApproachWe quantified the cumulative incidence of child protection contacts during childhood, including initial reports, screened-in reports, investigations, substantiations and removal into out-of-home-care, among all children in two Australian states. We used child protection system data linked for the South Australian (SA) BEBOLD and NSW Child E-Cohort data platforms as the numerator, and census data for the denominator, for 571,497 SA children (birth-years 1991-2019) and 1,362,505 NSW children (birth-years 2005-2018). ResultsOf children born in 2005 (NSW SA): Two in five children were reported to child protection by age 14; one in ten children were the subject of a child protection investigation in NSW and SA; one in twelve children in NSW and one in 17 in SA, were substantiated at least once; and one in 35 children in NSW and one in 40 in SA were removed into out-of-home care at least once by age 14. Approximately half of all types of child protection contact first occurred by the child’s fourth birthday. Conclusions/implicationsThe scale of lifecourse child protection contact underscores the opportunities for early health and social supports to prevent child maltreatment and escalating child protection intervention. Child protection reports also represent an asset to generate public health intelligence to inform early prevention.

IntroductionChildren who experience maltreatment have worse health and development outcomes than other children. Early prevention relies on opportunities to respond to system contacts that reliably indicate the population burden of children’s future developmental risk. Objectives and ApproachWe quantified the population burden of developmental vulnerability at age five by the type, timing, and frequency of child protection contacts before school, among children in two Australian states. We used linked whole-population births, child protection and Australian Early Development Census (AEDC) data (2009-2018 cycles) in New South Wales (NSW) and South Australia (SA). Results56,650/398,702 (14%) NSW and 12,617/80,731 (16%) SA children had ≥1 child protection contacts before school. The risk of developmental vulnerability on ≥1 domains was lowest in the no child protection group (NSW, 17-18%; SA, 19%), with higher risks in the child protection report (NSW, 28-29%; SA, 32-35%) through to the OOHC (NSW, 35-38%; SA, 39-50%) groups, with a similar pattern for the risk of medically diagnosed conditions. Children with only one child protection report before school had a higher developmental risk than the no child protection group (NSW, 34% versus 21%; SA, 42% versus 24%). Conclusions/ImplicationsEven a single child protection report in the first 2000 days of children’s lives was a robust indicator of developmental risk at age five, with higher developmental risks among children with more serious child protection contacts before school. Child protection reports represent an under-utilised asset to inform early universal and targeted support from health, human and early education services.

In this chapter, we outline an approach to preventing prison violence that is informed by the other chapters in this book. We adopt a broad public health approach to prevention based on the identification of risk factors and an understanding of why prison violence occurs before discussing the importance of returning "data to source" and partnering with key stakeholders to identify prevention initiatives that are likely to work in the specific setting or context under consideration. The chapter concludes with a discussion about some of the challenges faced by those seeking to implement violence prevention initiatives in prisons.

OBJECTIVES:To investigate the number of mental health-related hospitalisations of adolescents (12-17 years) in South Australia by level of contact with the child protection system (0-11 years). STUDY DESIGN:Whole-of-population descriptive study; analysis of de-identified linked administrative data from the Better Evidence Better Outcomes Linked Data (BEBOLD) platform. SETTING, PARTICIPANTS:Adolescents born in South Australia, 1991-1999; linked SA Department for Child Protection, Admitted Patient Care (SA Health), and South Australian Perinatal Statistics collection (SA Department for Health and Wellbeing) data. MAIN OUTCOME MEASURES:Proportion of adolescents (12-17 years) hospitalised with mental health-related diagnoses; proportion of mental health-related hospitalisations of adolescents, by level of child protection contact (0-11 years) (no contact, notification but not screened in, screened-in notification but not investigated, investigation but not substantiated, substantiation, and out-of-home care). RESULTS:Of 175 115 adolescents born during 1991-1999, 5646 (3.2%) had been hospitalised with mental health conditions, and 27 203 (15.5%) had histories of contact with child protection services. The proportion of adolescents admitted to hospital with mental health-related diagnoses increased with the level of prior child protection contact, from 3366 of 147 912 adolescents with no contact (2.3%), to 398 of 6645 with notifications (6.0%), to 209 of 1191 who had been placed in out-of-home care (17.5%). Contact with child protection services was recorded for 2280 of 5646 adolescents admitted to hospital with mental health-related diagnoses (40.4%); 4477 of 10 633 mental health-related hospitalisations (44.9%) were of adolescents with histories of child protection services contact, including 1285 hospitalisations (12.1%) of adolescents for whom substantiated maltreatment (but not out-of-home care) was recorded, and 568 hospitalisations (5.3%) of adolescents who had been placed in out-of-home care. CONCLUSION:About 45% of mental health-related hospitalisations of 12-17-year-old adolescents were of people who had had contact with child protection services by the age of 11 years, although only 15.5% of all adolescents had histories of child protection contact. The trauma associated with a history of child protection can have longer term sequelae, and this should be considered when adolescents are hospitalised with mental health conditions.

ObjectiveQuantify the scale and type of maternal substance use from conception to the child’s second birthday (First 1000 days) to inform screening and support services that may reduce associated harm or risk for children. ApproachWe used mother and child records from whole-population health, death, and child protection datasets to ascertain maternal substance use during the First 1000 days for children born in NSW, Australia, from 2008-2017. The primary outcome - maternal substance use - included use of illicit substances, alcohol, opioid-agonist treatment, organic compounds, solvents, and misuse of prescription medicines. ICD-10 and SNOMED-CT diagnosis codes were used. ResultsThe birth cohort included 970,470 children and 625,856 mothers. 32,000 children (3.4%) had a record of maternal substance use during the First 1000 days of life, including 13,647 (1.4%) with alcohol and 23,485 (2.4%) other drug use. Ascertainment was highest from child protection records (26,045 children), followed by mother’s (12,956 children) then children’s hospital records (3,826 children). 18,672 (1.9%) children had a record of carer substance use only in child protection records. Combining data increased the prevalence estimates; adding child protection records increased the prevalence estimate to 3.4%, compared with 1.2% in health and death records alone. ConclusionMore than 3 in every 100 Australian children had a record of maternal substance use in administrative data during the First 1000 days of life in this decade-long study. In addition to health and death data, child protection data offers public health insights into the scale of maternal substance use among whole-population cohorts of children.

ObjectiveTo describe how culturally and linguistically diverse (CALD) children are identified and enumerated in routine data collections and in child health research in Australia.MethodsDescriptive analysis, where different definitions of CALD were applied to the 2021 Australian Census to measure the size of the CALD population of Australian children aged 0 to 17 years. Narrative review of the Australian child health literature to examine how CALD children were defined.ResultsApplying various definitions to the 2021 Census, the estimated proportion of CALD children aged 0 to 17 ranged from 6.3% to 43%. The most commonly applied CALD indicators were language background other than English and being born overseas.ConclusionsThere is no consensus on how CALD is defined in Australian child health research. Application of different CALD indicators can generate up to seven-fold differences in estimates of who counts as being a CALD child.Implications for Public HealthIf we are to advance health and well-being equity for CALD children, we need a more consistent approach to understanding which children are counted as CALD.