Definition of terms
In this review child development refers to a measure of cognitive or physical or linguistic or socio-emotional development at primary school starting age (3-7 years).
Review Questions
The Preferred Reporting Items for Reporting Systematic Reviews and Meta-Analyses (PRISMA) guidelines (31) will be used to answer the following review questions:
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What are the associations between measures of child development recorded at primary school starting age (3-7 years) and subsequent health in adolescence (8 -15 years)?
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What are the effect modifiers (socioeconomic and environmental factors) of this relationship? (This will identify variables which alter the strength of the observed associations.)
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What are the mediators of this relationship? (This will identify variables or pathways which explain the observed associations.)
We have used the PRISMA-P checklist to develop this protocol (see additional file 1 for completed checklist).
Study Design
We will undertake a participatory systematic review, involving engagement with national and local stakeholders across health and education sectors. Participation will occur in the following ways: after an initial scoping search and review of papers, discussions with stakeholders will take place to identify any further relevant studies and to develop an initial conceptual model. This initial conceptual model will act as a framework for extracting and analysing evidence identified in the systematic review. The model will be revised and refined through analysis of the included literature. Narrative synthesis will be used to generate findings and produce a diagram of the relationship between child development in the early years of primary school and adolescent health outcomes. Where possible we will summarise effect sizes in meta-analysis. This participatory review method adds value over traditional review methods when clarifying underlying theory, ensuring all valued outcomes are captured, adding insight to relationships between outcomes and understanding of how, when and where interventions may work (32). Participatory methods to produce diagrams, maps or models help to uncover theories of change and assumptions underpinning pathways between cause and effect (33). They are increasingly recognised for their potential to make a contribution to systematic review methodology (34) and particularly in the field of public health (35).
Searches
MEDLINE, PsycINFO, ASSIA and ERIC will be searched for results from the past twenty years. The reference lists from all included articles will be searched for eligible articles that may have been missed by the electronic search. Further relevant literature will be identified through stakeholder discussions. Grey literature searching will be undertaken by searching relevant organisations websites and discussions with stakeholders, to find all relevant literature for inclusion. The search terms relate to measures of child development in the early years of primary school and health outcomes in early adolescence. Studies will be limited to those that include children, some or all of whom are aged between 3 and 15 years and those that are in English. A pilot search strategy has been undertaken – additional file 2.
Population, exposure, outcomes and study designs
The population and context, exposure, outcomes and study designs are described in relation to inclusion and exclusion criteria in Table 1.
Table 1
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Inclusion
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Exclusion
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Population and context
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Studies must include children, some or all of whom are aged between 3 and 15 years, across socioeconomic strata in high-income country settings, defined as OECD membership.
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Studies of children from non-OECD countries.
Studies which focus solely on a particular subset of children with a particular health or development need.
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Exposure
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A measure of child development at primary school starting age (3–7 years), defined as: cognitive or physical or linguistic or socio-emotional development at school starting age, measured by any of the following:
• School readiness, as measured by scales such as the Bracken Basic Concepts Scale Revised (BBCS-R)(36)
• Cognitive development as measured by, for example, non-reading intelligence tests, vocabulary tests, maths tests or parent/teacher ratings.
• Language and literacy (as measured by academic achievement test scores such as pre-reading/reading, vocabulary, oral comprehension, phonological awareness, pre‐writing/writing or verbal skills.
• Emotional well-being and social competence (as measured by behavioural assessments of social interaction, problem behaviours, social skills and competencies, child‐parent relationship/child‐teacher relationship).
• Physical development.
Studies that explore socioeconomic and environmental factors which affect associations between child development at primary school starting age and these outcomes
Studies that explore mechanisms or pathways child development at primary school starting age and these outcomes.
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Studies reporting neither data nor mechanism between exposure and outcome will be excluded.
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Outcome
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Main Outcome(s)
The review will incorporate evidence on all health and wellbeing outcomes, reported between the ages of 8–15 years, for example:
Weight (BMI)
Mental Health (as measured by standard questionnaires or clinically)
Socio-emotional behaviour
Proxy measures such as dietary habits and behaviour and measures of wellbeing will be included.
Additional Outcome(s)
Educational outcomes
Performance at the end of primary school (age 10–11), measured by standardized tests.
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Studies reporting neither data nor mechanism between exposure and outcome will be excluded.
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Study design
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Longitudinal studies, RCTs, Quasi experimental, review level studies including theory papers
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Conference abstracts, books, dissertations, opinion piece
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Development of the conceptual model
We have undertaken a scoping review to identify the main factors and pathways between child development at primary school starting age (3-7 years) and subsequent health outcomes at age 8-15 years. Meetings with five stakeholders from local authority, health, education and voluntary sector have been held in September 2020 to explore their perspectives on these pathway areas; considering in particular, the following:
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How health outcomes in adolescence are most affected by socioeconomic circumstances in child development at the start of primary school
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General perceptions of what the mediating pathways are, including how pathways are connected and feedback loops
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Where in the system would intervening have most impact on socioeconomic inequality in child development on later health outcomes in adolescence
Participatory methods and tools, including concept mapping approaches will continue to be used in these stakeholder meetings to finalise our conceptual model of the pathways (see Figure 1a for draft). This initial model forms a framework for the review and provides initial categories for extracting and analysing evidence from published studies. The model will then be revised and refined iteratively through analysis of the included literature to produce a final diagram. This will illustrate where factors in the initial diagram were not reported in the literature and where there may be associations and relationships between factors. The model will be used to formulate a directed acyclic graph (DAG) for further statistical analysis of the associations and pathways in subsequent phase of this study (see figure 1b).
Data Extraction
Articles will be screened using the inclusion and exclusion criteria at title and abstract level, and then at full article level. At each stage a sample will be checked by another member of the review team. Any queries regarding inclusion will be discussed with at least one other team member. Data extraction using a bespoke form will be undertaken for all studies that meet the inclusion criteria and second checked. A data extraction form has been developed using previous expertise of the team, and trialled on a sample of different sources. The following data will be extracted: Study design, Country, Year, Study population, Study characteristics, Child development measure, Health outcomes, Factors affecting associations, Pathways, Main findings, Strengths & weaknesses
Quality Assessment
Quality assessment of the included studies will be conducted using the Liverpool University Quality Assessment Tool (LQAT), which allows for a specific tool to be used for each study design (37). This tool has been independently evaluated against other quality assessment tools (38). Quality assessments will be done by the main author and second checked by a member of the review team and any discrepancies will be discussed.
Strategy for Data Synthesis
This participatory systematic review has been informed by an initial scoping review and stakeholder engagement. Narrative synthesis and meta-analysis (where possible) will be used to generate findings and will inform a final diagram of the relationship between child development at primary school starting age and health outcomes in early adolescence.