This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced by any process without prior written permission from the Commonwealth, available from AusInfo. Requests and inquiries concerning reproduction and rights should be addressed to the Manager, Legislative Services, AusInfo, GPO Box 1920, Canberra ACT 2601.
The views expressed in this paper are those of the authors and do not represent the views of the Minister for Family and Community Services or the Department of Family and Community Services.
This review was undertaken by a multi-disciplinary team from the Centre for Community Child Health that comprised:
Dr Debra Foley
Dr Sharon Goldfeld
Ms June McLoughlin
Ms Jeanette Nagorcka
Prof Frank Oberklaid
Dr Melissa Wake
The Centre for Community Child Health would like to extend its gratitude to the following people who assisted with the review by providing critical material that might not otherwise have been obtained within the very limited time-lines for this project: Associate Professor Dorothy Scott from The University of Melbourne, Dr Lyn Littlefield and Ms Donna De Borteli from the Victorian Parenting Centre, Dr Tim Moore from the Monnington Centre, Ms Robyn Le Broque from Queensland University and Dr Gay Ochiltree.
Ms Emma White from the Centre for Community Child Health provided assistance in acquiring material for the review and compiling this document.
1. Executive Summary 1
2. Introduction 3
3. Developmental Delay 3
4. Risk/Protective Factors: What Determines Outcomes? 4
4.1 Introduction 4
4.2 Major studies reviewed 5
4.4.1 Complex Interaction Between Risk Factors 5
4.4.2 Risk and Protective Factors Vary According To Life Stages 13
4.4.3 Pathways Through Childhood 13
5. Intervention Studies: How Can We Influence Outcomes? 14
5.6 Programs for children with developmental delay or disability 28
6. Cost Effectiveness 30
7. The Australian Context 30
1. EXECUTIVE SUMMARY
The current international debate about the importance of the early years of life for subsequent health, development and well-being in childhood, adolescence and adult life, has focused attention on the growing literature in this area. This research has the potential to impact on the way government systems deliver services to children and families, and therefore requires careful consideration within an Australian context.
This document briefly reviews selected literature relating to the major risk and protective factors that may influence children’s developmental outcomes in the preschool years. It then reviews selected studies of the preventive and early interventions that may impact on these outcomes.
The literature review was conducted over three weeks in September 1999. The short time frame precluded identification of all relevant high-quality literature and prevented the acquisition of some of the material identified through the searching process as potentially relevant.
A number of longitudinal studies are reviewed in order to identify early childhood risk and protective factors. Important risk factors include: perinatal stress; difficult temperament; poor attachment; harsh parenting, abuse or neglect; parental mental illness or substance abuse; family disharmony, conflict or violence; low socioeconomic status; and poor links with the community. Important protective factors include: easy temperament; at least average intelligence; secure attachment to family; family harmony; supportive relationships with other adults; and community involvement.
The review explores the complex relationship between these risk and protective factors, their variation during different life stages and pathways through childhood with which they may be associated. It notes that while adverse outcomes are associated with these risk factors, some children exhibit resilience and do not experience adverse outcomes.
A range of early intervention programs that seek to improve outcomes for children and/or families were identified. These include: preschool and child care (both universal services and targeted/enhanced early childhood programs); child health surveillance; home visiting; parent education; and programs for children with developmental delay or disability.
High quality studies of the effectiveness of these interventions were reviewed. Key findings include:
• Participation in a preschool program promotes cognitive development in the short term and prepares children to succeed in school (Boocock 1995).
• Preschool experience appears to be a stronger positive force in the lives of low income than advantaged children (Boocock 1995).
• Maternal employment and participation in out-of-home care, even during infancy, appear not to harm children and may yield benefits if the child care is regulated and of high quality (Boocock 1995).
• Early childhood and development programs can produce large increases in IQ during the early childhood years and sizeable, persistent improvement in reading and maths, decreased need for grade retention and special education, and improved socialisation for disadvantaged children (Barnett 1995).
• Anticipatory guidance, a common feature of child health surveillance programs, can improve nutrition, some aspects of behaviour and development, and parenting (Dworkin 1998).
• Home visiting programs can be effective, particularly for very disadvantaged women, but there have been great difficulties in implementing and operating these programs (The Future of Children 1999).
• Group-based parenting education programs, particularly those taking a behavioural approach, can produce positive changes in children’s behaviour (Barlow 1997).
• Community based group education programs for parents produce more changes in children’s behaviour and are more cost effective and user friendly than individual clinic-based programs (Barlow 1997).
• Early intervention programs for children with a developmental delay or disability increasingly focus on broad family outcomes rather than specific developmental gains for children (Guralnick and Neville 1997).
The review examined a US study of the cost effectiveness of early intervention programs which found that for some disadvantaged children and their families, considerable cost savings could be made by investing in early intervention (Karoly 1998).
The review places these findings into the Australian context. Few Australian early childhood programs have been studied using rigorous research methods. While much can be learned from international studies of interventions in early childhood, extrapolation of the results to the Australian situation should be undertaken cautiously and should take into account existing local service systems, socio-economic patterns and cultural characteristics (Vimpani 1996). Interventions conducted outside Australia have sometimes targeted families who are much more deprived than their local counterparts. The utility of applying similar interventions to Australian society can therefore not always be inferred from international data.
Finally, the review suggests that there may be an association between quality universal early childhood services and positive outcomes (Boocock 1995).
There is a growing international literature surrounding the importance of the early years of life. This research has the potential to impact on the way government systems deliver services to children and families, and therefore requires careful consideration within an Australian context.
This document has been designed to give a brief review of the literature relating to the major risk and protective factors that may influence children’s developmental outcomes in the preschool years. This has been coupled with a review of the preventive and early interventions that may impact on these outcomes. It reflects research that has been conducted over the last decade and has led to the development of a greater understanding of the importance of the early years of childhood. These sections are preceded by a discussion of the wide range of factors that may contribute to developmental delay and the complex relationships between them.
3. DEVELOPMENTAL DELAY
A traditional focus on trying to identify single biological and/or environmental factors that cause developmental delay has in recent years been replaced by a model of child development that emphasises the complex dynamic interplay between biological factors within the child and the caretaking environment. This transactional model postulates that developmental outcomes are the end result of a complex transaction between intrinsic or within child factors (eg. genes, central nervous system development, temperament) and environmental factors (eg. parenting style, amount of stimulation, socio-economic status).
A wide range of biological factors have been identified as causing or contributing significantly to poor developmental outcomes. These include: genetic disorders (chromosomal abnormalities, specific syndromes); structural malformations of the brain (microcephaly, hydrocephaly); infections of the central nervous system (cytomegalovirus, rubella, toxoplasmosis); toxic insults to the developing central nervous system (irradiation, drugs, alcohol); malnutrition; and perinatal stress (cerebral hypoxia, brain haemorrhage). As mentioned earlier, for most children the transactional model of development means that these biological insults should be regarded as being ‘risk factors’ which create vulnerability for the infant rather than resulting in inevitable poor outcomes. This vulnerability can be heightened or diminished by environmental factors. “A premature infant who struggles through multiple medical complications and is discharged from a neonatal intensive care unit to a nurturing home with excellent social supports is likely to do well developmentally; another baby with an identical medical history who is reared in an unstable environment by an isolated, disorganised and highly stressed single parent is likely to have a host of developmental difficulties”. (Shonkoff and Marshall 1990). It should also be remembered that in a significant minority of children with developmental delay, no specific biological factors can be identified.
A host of environmental risk factors has been identified as contributing to poor developmental outcomes. These factors relate to the quality of the caretaking environment, and are influenced by characteristics of the parents, socioeconomic determinants, the level of stress and support experienced by the family, the level and intensity of early learning experiences the child has, parenting style and family functioning, and parental mental health. A biologically intact infant who experiences a poor caretaking environment is potentially at risk of mild to moderate developmental delay. Children at risk for the worst developmental outcomes are those who have a combination of biological and environmental risk factors; these risk factors operate in a cumulative fashion, so that the more risk factors present the greater the likelihood of a poor developmental outcome.
Attempts to improve developmental outcomes have focused on a variety of interventions at a biological and environmental level. Many interventions have been shown to minimise biological risk. These include ensuring complete immunisation to reduce the risk of maternal infection during pregnancy (e.g. rubella); giving folate supplements during pregnancy to reduce the risk of structural abnormalities of the central nervous system such as anencephaly and spina bifida; advising pregnant women to significantly decrease or refrain from alcohol, tobacco and drug use during pregnancy; testing for genetic disorders during the first trimester of pregnancy and providing specialised genetic counselling in instances where there is a family history of developmental disability; and fetal monitoring for high risk pregnancies.
Similarly there have been attempts to minimise environmental risk with a host of intervention programs designed to improve the quality of the caretaking environment by offering parent support and education, and early education programs designed to provide rich and stimulating learning experiences for infants and young children. These are explored in detail in this review.
4. RISK/PROTECTIVE FACTORS: WHAT DETERMINES OUTCOMES?
Longitudinal studies, by examining the life course and circumstances of a group of individuals over time, identify the factors that are associated with an increased likelihood of negative outcomes (risk factors) and those that are associated with a decreased likelihood of negative outcomes (protective factors).
One important advantage of longitudinal studies is the ability to investigate relationships between measures taken early in a child’s life and outcomes in later childhood, adolescence and adult life. Such studies can therefore identify factors that might be causally related to later problems, and may thereby guide the design of interventions. Given the richness of the data collected by many longitudinal studies, a wide variety of putative risk and protective factors can now be evaluated. Variation in the measures obtained by different studies across time, however, makes any synthesis of the literature a challenging task.
4.2 Major studies reviewed
A number of longitudinal studies were reviewed. The longitudinal studies summarised in Table 1 (pp8-11) identify a variety of individual, familial and community risk and protective factors for young children that are associated with differential outcomes over time. These risk and protective factors, together with others identified from additional studies referred to briefly in this section, are summarised in Table 2 (p.12) and Table 3 (p.13) respectively. The longitudinal studies also serve to highlight two important findings. Early childhood risk factors are associated with a wide variety of adverse outcomes, and these may be evident in either the short or the long-term. The major adverse outcomes associated with early childhood risk factors are summarised in Table 4 (p.14).
These tables provide an overview of the risk and protective factors that may impact on young children and identify the range of possible adverse outcomes. The relationship between these factors is quite complex, however, and warrants further comment.
4.2.1 Complex Interaction Between Risk Factors
Risk factors for adverse outcomes often co-occur, and they may have cumulative effects over time. Common indices of family adversity, for example, often cluster together and appear to have long standing effects on children’s health and development. Results from the Dunedin Longitudinal Study indicate that ongoing family adversity is a risk factor for attention difficulties, poor cognitive performance and delinquency (Silva and Stanton 1996). Family disadvantage has also been linked with greater absenteeism from school due to ill health, and a lower usage of preventative health services such as immunisation (Power 1992). The cumulative effect of familial stressors such as low socioeconomic status, young maternal age at birth, large family size and family instability may therefore have a pervasive effect on the well being of young people. These results – the cumulative effects of multiple risk factors – have been confirmed by the Australian Temperament Study (Sanson et al. 1991).
The numerous factors commonly summarised as family disadvantage or family adversity by these longitudinal studies may have a multiplicative effect on the risk of adverse outcomes in children. Rutter (1970; 1978), for example, demonstrated that children exposed to six indices of family adversity had 20 times the risk of adverse behavioural or cognitive outcomes compared to children exposed to one or none of the same risk factors. It is important to note that familial risk indices may index a diversity of genetic and environmental risk factors. Parents may transmit genetically mediated risk or protective factors to their children, and they also provide the child’s rearing environment. A child’s genotype is therefore correlated with their family environment, and genetic and environmental risk or protective factors may interact in a very complex fashion (eg. Goodman and Gotlib 1999).