Health outcomes of experiencing poverty in the early years: evidence review

Chapter 1: Introduction and context

Child poverty in Scotland

Research shows persistent health inequalities for children in Scotland^[1] with disparities starting from birth and continuing throughout their lives^[2]. These inequalities are closely linked to poverty. Poverty estimates after housing costs in Scotland suggest that, in 2021-24, 23% of children were living in relative poverty and 20% of children were living in absolute poverty.^[3] While, in 2023-24^[4], it is estimated that 9% of children were living in combined low income and material deprivation after housing costs^[5]. Furthermore, 22% of children were living in households with marginal, low or very low food security^[6].

Poverty is not equally dispersed across the population. Some types of households are at greater risk of living in poverty^[7]. Six priority family types have been identified by the Scottish Government as being at higher risk of child poverty. These are:

• Households with 3 or more children.
• Households with one or more disabled members.
• Households of a minority ethnic background.
• Lone parent households.
• Households with a mother aged under 25, and
• Households with a baby under 1^[8].

While these household types do not cover everyone at higher risk of poverty, taken together, they cover the majority of households in Scotland with children living in poverty^[9]. Recent estimates show that only 7% of children in relative poverty lived in households outside of the identified priority groups in 2021-2024. On the other hand, 35% of children in households with a child under one were in relative poverty, compared to 23% of children overall. Additionally, 36% of children in relative poverty were in lone parent households, and 41% were in households with three or more children^[10].

Public Health Scotland (PHS) state that the ‘unequal distribution of income, wealth and power in society means that those families with less access to these experience poorer life experiences and poorer health’^[11]. These experiences vary by family, with some facing multiple disadvantages and adversities^[12]. These issues are often deeply interconnected, overlapping and intersecting with each other and with poverty in complex ways. Families facing multiple disadvantages and adversities are often among those deepest in poverty and face particularly challenging journeys to get out^[13].

Poverty and health are interconnected. Experiencing poverty can increase the risk of poor health outcomes, and a person's health status can increase their risk of experiencing poverty^[14]. Although there is not a simple causal relationship, multiple disadvantages and adversities can make it harder to get out of poverty and poverty can also make it harder to overcome adversities. These complex interactions can create a cycle where poor health and poverty reinforce each other, perpetuating inequalities^[15].

Given this context, the period before conception and birth, and the early years, represents a critical window for promoting healthy development, breaking poverty cycles and tackling intergenerational inequalities^[16]. Preparing for pregnancy, before conception, is highlighted in the literature as a key strategy to optimise population health, reduce inequalities, prevent diseases across the lifespan and promote intergenerational health^[17]. Good health in the preconception period is particularly important for those with pre-existing physical and mental health conditions, with evidence that those in some minority groups and those living in more deprived areas are at higher risk of these conditions^[18]. Evidence indicates that maternal and paternal obesity, dietary deficiencies, smoking, alcohol consumption, drug use and mental health issues often compromise preconception health^[19]. Entering pregnancy with such conditions significantly heightens health risks for both parents and children and can contribute to the transmission of inequalities across generations^[20]. Strengthening preconception care and early interventions can therefore better support those with complex needs while promoting healthier outcomes across society. This will be developed in further detail in Chapters 3 and 4 (The health outcomes of experiencing poverty in the early years and Moving forward: overarching evidence).

Interventions at this stage can offer lifelong benefits^[21]. Investing in primary prevention^[22] – stopping health problems that can be prevented from arising in the first place – is linked with a high rate of return on investment^[23]. Preventive measures can also yield significant health benefits, such as fewer child hospitalisations, improved child oral health, improved parental mental health, reduced child asthma rates, prevention of premature births and child disease prevention^[24]. Importantly, children living in poverty can benefit from targeted efforts as they face higher health risks^[25].

These outcomes are mediated by different mechanisms. These include more equitable income distribution as a result of policy measures related to the labour market, welfare, educational system and poverty reduction; reduced exposure and vulnerability to risk factors as a result of targeted initiatives and improvements to housing, working conditions and health services; reduction of the negative social outcomes of poor health as a result of social protection initiatives, for example improved access to joined-up, holistic services and improved quality of life in the home; and strengthening support for nurturing care among families and caregivers^[26].

Child development, poverty, and health across the life course

Child poverty differs from adult poverty due to its potentially lifelong effects on children's biological, social, cognitive and emotional development^[27]. Epigenetic research, which explores the role that environments play in how the genetic code itself is expressed, can be useful in understanding the link between early adversity and future outcomes^[28]. The early years of life are a critical developmental period, characterised by rapid brain development and heightened sensitivity to environmental stimuli^[29]. This means that children are most susceptible to their environmental influences during these years, with rapid development of their physical, emotional, social, and cognitive capabilities^[30]. This susceptibility to environmental influences is linked to an increased vulnerability to disruptions in epigenetic mechanisms^[31]. Disruptions can result in an altered gene expression that continues through subsequent cell cycles and drives a changed developmental programme^[32].

As this period is critical for laying the foundation for health and wellbeing, experiencing poverty at this life stage can threaten childhood development, as well as present and future health trajectories^[33]. Living in poverty often goes hand in hand with other forms of deprivation and intersects with other challenges and risk factors that may accumulate over time^[34]. Examples include struggling to afford basic material items, such as food and warm clothing, and living in poor quality housing^[35]. These experiences can deprive children’s brains of essential stimuli and expose them to high levels of stress^[36]. Additionally, living in poverty can impact on cognition, specifically speech and language development, executive functioning, self-regulation and social interactions, generating the circumstances underlying adverse health risks^[37]. While children out of poverty may also face cognitive delays and high stress, those in poverty generally encounter more adversities and may have fewer resources to mitigate these challenges^[38]. These inequalities can impact health and development in ways that contribute to the transmission of inequalities from one generation to the other (Figure 1).

The pathobiology of poverty in childhood is summarised by Lee et al^[39]. Their framework demonstrates how adverse conditions associated with poverty including poor nutrition (unhealthy food and lack of healthy food), antenatal and childhood psychological stress, exposure to pollution (poor indoor and outdoor quality air), and poor sleep quality can lead to:

• Inflammatory dysfunction: elevated levels of inflammatory markers like interleukin-6 and C-reactive protein.
• Metabolic dysfunction: disruptions in fat and glucose metabolism.
• Endocrine dysfunction: altered hormone levels, including cortisol and insulin.

These biological changes can impair the development of vital systems, including the cardiorespiratory, renal, and musculoskeletal systems. This can increase the risk of illness in both childhood and adulthood. The article also highlights that the effects of poverty are not confined to a single generation. Children affected by poverty-induced biological changes may experience health issues that persist into adulthood and can influence the health of their own children, perpetuating the inter-generational cycle of poverty.

The life course perspective suggests that growing up in poverty can lead to lasting health problems throughout a person’s life^[40]. Some findings on the long-term health outcomes of experiencing poverty in the early years are presented below for context, however this falls beyond the scope of this report, which is focused on the impacts within the early years themselves.

Cohort data show that children experiencing poverty prior to age three tend to have poor health which results in long-term adverse health outcomes at age 12^[41]. Analysis using data from the ‘Growing Up in Scotland’^[42] (GUS) longitudinal study shows that, at age 14, young people in less deprived areas (SIMD quintiles^[43]) were more likely than young people in more deprived areas (SIMD quintiles) to say that their health was 'excellent', and parents of young people in less deprived SIMD quintiles were more likely than parents of young people in more deprived SIMD quintiles to say that their own health was excellent or very good^[44]. Further analysis using data from the GUS longitudinal study shows that poverty trajectories and unstable work have a significant effect on child development, particularly trajectories of behavioural and emotional problems in children^[45].

Additionally, international evidence highlights a clear relationship between childhood socioeconomic position (SEP) and the risk of Adverse Childhood Experiences (ACEs) and maltreatment, consistent across countries, measures, and ages at which adversity was assessed^[46]. Further evidence highlights that individuals who reported four or more childhood adversities were at notably greater risk of a wide range of issues in later life (including cancer, heart disease, respiratory disease, mental illness and self-harm), compared to individuals that had no experience of ACEs^[47]. Additionally, poor health in the early years is linked to reduced educational attainment, higher unemployment rates, and decreased productivity in adulthood^[48], with socioeconomic disadvantage further associated with premature mortality (i.e. before age 75)^[49].

Different theories have been developed to explain the pathways through which these effects take place. These include material pathways, which highlight the lack of access to essential resources, such as food and warm clothing; psychosocial pathways, which emphasise the mental and emotional strain caused by a lack of control and experiences of stress; behavioural pathways, which explore health inequalities through patterns of healthy and unhealthy behaviours; and structural pathways, which focus on systemic barriers such as unequal distribution of resources. Taken together, these pathways provide a comprehensive understanding of how poverty impacts health, as discussed further in relevant analysis^[50]. Research suggests that there may be a number of factors mediating these links, however the home linguistic environment (quality and quantity of linguistic input) and family stress are two central components^[51].

UNICEF analysis indicates that the lifelong impacts of poverty may stem from the stress it places on developing brains and bodies^[52]. Persistent stress responses in early childhood, for example in response to stressors relating to poverty, can cause wear-and-tear on biological systems, undermining both physical and mental health^[53]. These repeated stress activations are linked to increased risk of adult health concerns, such as stress-related disorders, cardiovascular disease, obesity, type 2 diabetes, respiratory and immunological disorders, and various mental health issues^[54]. Further evidence suggests that stress and lack of control over life circumstances also follow a social gradient^[55], affecting key executive functions like memory development and self-regulation^[56]. These findings highlight that addressing child poverty and its health impacts is essential to promoting healthier lifelong outcomes.

Tackling child poverty

In Scotland, the Child Poverty Act 2017 acts as a legal framework for tackling child poverty and sets out a requirement to meet four income-based targets by 2030 (Relative Poverty, Absolute poverty, Combined material deprivation and low income and Persistent poverty). Poverty targets^[57] are set based on poverty after housing costs (AHC) and these require:

• Fewer than 10% of children living in families in relative poverty (living in a household with an equivalised income^[58] below 60% of UK median income in that year).
• Fewer than 5% of children living in families in absolute poverty (living in households with an equivalised income below 60% of UK median income in some base year, usually 2010/11).
• Fewer than 5% of children living in families living in combined low income and material deprivation (living in a household with below 70% of UK median incomes in that year, plus whose parents want but cannot afford specific goods or services for their children or for themselves).
• Fewer than 5% of children living in families in persistent poverty (living in relative poverty for three or more of the last four years).

Tackling child poverty and health inequalities in the early years requires a coordinated, long-term approach across policy areas and organisations to address the complex challenges families in poverty face^[59] and the additional barriers faced by those experiencing intersecting inequalities, for example those living in low-income households and managing caring responsibilities. Scotland has a long-standing commitment to tackling these issues. In alignment with the vision of Scotland as a country ‘where people live longer, healthier, and more fulfilling lives’^[60], eradicating child poverty is a key priority within the Scottish Government’s Programme for Government^[61]. Two child poverty delivery plans have been guiding a wide range of action across the three main drivers of poverty (increasing income from employment, reducing costs of living and increasing income from social security and benefits in kind^[62]) to help people into fair, well-paid jobs (i.e., Fair Work^[63]), support people with the cost of living (i.e., Scottish Child Payment^[64]) and increase awareness and uptake of social security benefits^[65]. Support is being targeted at those priority families at higher risk of poverty^[66]. Additionally, a series of measures focus on other mechanisms to reduce poverty in relation to improving the quality of life and wellbeing of children and families^[67] (i.e., investing in perinatal and infant mental health^[68]).

The commitment to a preventive, whole system approach to addressing child poverty is further supported by the Population Health Framework. The Framework has been co-developed by the Scottish Government and COSLA, in partnership with Local Government, the NHS, PHS, community and voluntary sector, business and communities themselves. It takes a long-term approach to prevention in order to accelerate the improvement and recovery of population health in Scotland and reduce inequalities. The Framework includes a focus on improving health during pre-conception, pregnancy and the early years.

Additionally, as part of wider health and social care reform efforts, the Health and Social Care Service Renewal Framework (SRF) focuses on key areas of reform to enhance prevention, identify risk factors earlier, and expand early intervention and proactive care.

It is important to note broader UK policies influence the socioeconomic conditions in which Scottish initiatives operate. For example, UK-wide policies – such as Universal Credit (UC) and the two-child limit, which limits the number of children families can claim benefits for – impact household incomes and financial security in Scotland. The Scottish Government continues to explore and introduce measures to mitigate some of these impacts^[69].

This evidence review forms a part of the wider evidence base the Scottish Government is developing (summarised below) around eradicating child poverty and the range of actions required to support the health and wellbeing of children. The review contributes to the evidence base by bringing together research highlighting poor child health outcomes associated with experiencing poverty and/or living in more deprived areas during pregnancy and the early years. Rather than attempting to cover all aspects of child health affected by poverty or the wide range of socioeconomic determinants influencing it, the report draws on a selection of key health indicators and related literature (approach described in more detail in Chapter 2: Methods) to explore the relationship between child poverty in the early years and health in the short and medium term. As such, findings are presented through a health-focused lens to support policy development and consider the use of indicators in monitoring health outcomes in Scotland.

Indicative list of Scottish Government's broader work aimed at tackling child poverty includes various types of publications:

Strategy/plan publications:

• Best Start, Bright Futures: tackling child poverty delivery plan 2022 to 2026
• Every child, every chance: tackling child poverty delivery plan 2018-2022

Research and analysis publications:

• Tackling child poverty priority families overview
• Child and parental wellbeing: measuring outcomes and understanding their relation with poverty
• Tackling child poverty - progress report 2023-2024: annex A - measurement framework
• Tackling Child Poverty Delivery Plan 2022-26: Evaluation approach to system change
• Tackling child poverty - place-based, system change initiatives: learnings
• Child poverty cumulative impact assessment: update
• Children, young people and families outcomes framework - core wellbeing indicators: analysis

Accredited official statistics publication:

• Poverty and Income Inequality in Scotland 2021-24

Framing the wider determinants of health

Poverty is one of many social, economic, and environmental factors that can intersect and influence people’s health^[70]. These interacting factors are known as the social determinants of health as they shape health and wellbeing outcomes in complex ways^[71]. They include material circumstances, the social environment, psychosocial factors, behaviours, and biological factors^[72].

The social determinants can act as risk factors that may increase children’s risk of experiencing physical and mental health issues but can also act as protective factors that may mitigate these risks^[73]. World Health Organization^[74] findings suggest that they may have a greater impact on health outcomes than both health care and lifestyle choices.

Various frameworks have been developed to present the social determinants of health in a comprehensive way, with varying focus on adult and child health. Some of these include the King’s Fund population health pillars^[75], the Marmot Review Conceptual Framework^[76] and the Social Determinants of Health (SDH) Framework for children^[77]. Despite their differences, these frameworks suggest that health is influenced by immediate, broader and macro-level factors that are interconnected and affect health outcomes both within and across the layers.

These determinants interact with inequality. A model developed by Health Scotland (now part of PHS)^[78] suggests that existing widespread inequalities in, for example, income, housing, and the physical environment interact from a broad, societal level down to the individual level, leading to health inequalities as a result (Figure 2)^[79] . Specifically, the model argues that health inequalities arise from a complex interplay of factors that operate at multiple levels. At the root are fundamental causes, which include global economic forces, macro socio-political and environmental, political priorities and decisions, and societal values related to equity and fairness. These forces drive the unequal distribution of income, power, and wealth, leading to poverty, marginalisation, and discrimination. These structural drivers shape wider environmental influences such as access to quality education, employment, housing, services, and social and cultural opportunities. These, in turn, affect people's individual experiences, including their economic and work conditions, physical environment, access to services, learning opportunities, and social and interpersonal relationships. The cumulative effect of these exposures leads to inequalities in health outcomes, including differences in wellbeing, healthy life expectancy, levels of illness (morbidity), and premature death (mortality). Addressing these inequalities requires action at all levels: undoing the fundemental causes, preventing harmful environmental influences, and mitigating the effects on individual experience.

Evidence surrounding the social determinants of health indicates that improving child health outcomes cannot be achieved in isolation; it requires a system-wide, interconnected approach that considers overall health improvement and addresses inequalities across the whole Scottish population and across the life course^[80]. This should involve interventions both within and beyond the healthcare system that holistically address areas related to the social determinants of health, including income, housing, social care, education and the built and natural environment^[81]. Taking an intersectional approach, which takes into account combinations of characteristics that shape experiences and how these are understood within systems and structures of power, is central to addressing the intersecting adversities and inequalities. Place-based approaches, currently implemented in the Scottish context, are also key to these efforts, as they can help break down organisational and sectoral barriers by fostering collaboration and integrating resources, investment, and expertise. This strengthens local services, making them more responsive to local needs, which is key to driving better outcomes for people and communities^[82].

This discussion on the wider determinants of child poverty, health, and health inequalities is not intended to be exhaustive, but to frame these issues and the broader context within which interactions between child poverty and health outcomes are operating. We recognise the complexity of these interactions and the limitation of one evidence review in bringing out the nuance of these adequately.

Terminology

‘Child poverty’ in the literature

Children are not a homogeneous group and experience poverty in different ways that may be interrelated^[83], for example lacking access to financial and nutritional resources essential for survival and development, lacking family and community structures that provide nurturing care and protection, and growing up without opportunities for voice^[84]. These varied experiences influence how child poverty is defined and measured in the literature^[85]. Definitions include income-based measures of poverty (such as absolute low income and relative low income), deprivation-based measures (such as material deprivation) and domain-specific measures (such as fuel poverty and food poverty)^[86]. Beyond the income perspective, evidence suggests that child poverty should also be understood as a deprivation of capabilities – such as inadequate nourishment, a lack of access to basic health services, social discrimination and political exclusion - framing it as a human rights issue^[87]. This view aligns with the incorporation of the UNCRC into domestic law in Scotland, which highlights the commitment to legally protecting children^[88].

Analysis highlights that a range of measures is required to capture different aspects of poverty and address its complexity^[89]. Using individual measures of living standards and child-focused measurement would be important steps to gain a more comprehensive understanding of child poverty and health inequalities^[90].

The use of ‘child poverty’ in this report

This report provides an overview of the literature on ‘child poverty’, within which there may be a range of definitions or measures used. In addition, it explores what is known about child health outcomes drawing on analyses using the SIMD^[91] to understand how these vary by deprivation. It is worth noting that the different datasets used to analyse health outcomes do not allow for a direct measurement of children in poverty.

The SIMD offers a consistent and nationally recognised approach to the identification of areas of multiple deprivation in Scotland, combining seven domains or aspects of deprivation: income, employment, health, education, skills and training, geographic access to services, crime and housing ^[92]. Importantly, evidence shows that the same areas that show income deprivation also show health deprivation^[93]. However, it is important to note not all children in poverty live in deprived areas and not all children living in deprived areas live in poverty^[94].

‘Early years’ in the literature

In the sources reviewed, there is some variation in how the term ‘early years’ is used. The term can be cross-cutting, referring to different aspects of child health and growth. Certain sources, particularly in the context of education, define early years as the first 8 years of life^[95]. Other sources use it to refer to the first 5 years, before formal schooling begins^[96]. Finally, sources primarily in the health and development sphere use the term to frame either the first 3 ^[97] or the first 4 years of life^[98].

Despite these variations, the term ‘early years’ is consistently used in the literature to emphasise the importance of early childhood as a foundational period for health and development and there are some common defining elements. The majority of definitions highlight the critical role of parents and caregivers^[99], the importance of a preventive approach^[100] and the need for a holistic view of child health^[101], which is particularly highlighted in the World Health Organization’s Nurturing Care Framework^[102].

The use of ‘early years’ in this report

In this review, the term ‘early years’ is used to refer to the period between pre-conception and 3 years, in alignment with Scottish Government policy (see the Early Child Development Transformational Programme^[103]) and World Health Organization evidence^[104]. This definition is adopted based on evidence of maximal rates of brain activity and growth, as well as developmental sensitivity during these years (as discussed above), making them a pivotal time for policy focus.

The terms ‘infant’, ‘child’, ‘young child’ ‘offspring’, and ‘baby’ are used interchangeably to refer to this time period.

Overview of the report

Following on from this introductory chapter, the remainder of the report follows this structure:

Chapter 2 (Methods) provides an overview of the research questions that informed the review; the methods used; the approach taken with regards to the use of key health indicators and related literature; the indicator selection process; and some key limitations of the report.

Chapter 3 (The health outcomes of experiencing poverty in the early years) presents findings on parental and child health in the early years in the context of poverty and health inequalities using the selected indicators.

Chapter 4 (Moving forward: overarching evidence) presents overarching findings from the literature to mitigate or prevent poverty-related adverse health outcomes for children.

Chapter 5 (Conclusions) summarises the report’s conclusions.