Health and development from preconception to 20 years of age and human capital

Summary

Optimal health and development from preconception to adulthood are crucial for human flourishing and the formation of human capital. The Nurturing Care Framework, as adapted to age 20 years, conceptualises the major influences during periods of development from preconception, through pregnancy, childhood, and adolescence that affect human capital. In addition to mortality in children younger than 5 years, stillbirths and deaths in 5–19-year-olds are important to consider. The global rate of mortality in individuals younger than 20 years has declined substantially since 2000, yet in 2019 an estimated 8·6 million deaths occurred between 28 weeks of gestation and 20 years of age, with more than half of deaths, including stillbirths, occurring before 28 days of age. The 1000 days from conception to 2 years of age are especially influential for human capital. The prevalence of low birthweight is high in sub-Saharan Africa and even higher in south Asia. Growth faltering, especially from birth to 2 years, occurs in most world regions, whereas overweight increases in many regions from the preprimary school period through adolescence. Analyses of cohort data show that growth trajectories in early years of life are strong determinants of nutritional outcomes in adulthood. The accrual of knowledge and skills is affected by health, nutrition, and home resources in early childhood and by educational opportunities in older children and adolescents. Linear growth in the first 2 years of life better predicts intelligence quotients in adults than increases in height in older children and adolescents. Learning-adjusted years of schooling range from about 4 years in sub-Saharan Africa to about 11 years in high-income countries. Human capital depends on children and adolescents surviving, thriving, and learning until adulthood.

Introduction

Children's optimal health and development are the ambition of families everywhere and are central to the formation of human capital. The World Bank's Human Capital Project uses the Human Capital Index, which includes measures of mortality, growth, and education, to assess how countries invest in the capabilities and economic potential of citizens.¹ A broadened concep-tualisation of human capital should include health and wellbeing, the knowledge, and interpersonal and socioemotional skills needed to fulfil individual and societal potential. Human capital is formed through intergenerational factors and interactive biological–environmental–behavioural processes; it originates before conception and extends throughout childhood, adolescence, and beyond.2, 3

The Sustainable Development Goals (SDGs), agreed to by all UN member states, provide a pathway to human flourishing and the development of human capital.⁴ During the 25 years of the Millennium Development Goals (MDGs)⁵ era, from 1990 to 2015, child mortality was halved, including in many of the world's poorest countries, through societal progress and direct health interventions.⁶ Achieving the ambitious SDGs in the 15 year timeframe (2015–30) will require faster progress. The SDGs are broader than the MDGs, with an ambitious agenda. First, they go beyond survival to children thriving,⁴ including goals for nutrition, child development,⁷ and education;⁸ all important for human capital formation.³ Second, they adopt a life course approach, which extends beyond 5 years, to include school-age children and adolescents.² Third, the SDGs are more ambitious than the MDGs and aim for wider transformation in health and educational systems and other changes in multiple sectors that affect health and wellbeing.⁴ Finally, the SDGs extend beyond a focus on health and education to include economic and environmental goals, along with the social responsibility necessary to ensure sustainability.

The four papers in this Series on optimising child and adolescent health and development aim to explore the determinants and building blocks of thriving, from preconception through fetal development up to 20 years of age. In this first Series paper, we consider conditions of survival, growth, disability, and education in world regions and evidence from longitudinal studies on the crucial periods in the life-cycle before adulthood that build the foundation for human capital. Subsequent Series papers consider the importance of inequities in the determinants of human capital,⁹ interventions that have proven to be of benefit,¹⁰ the important need to improve quality of health services,¹¹ and the way forward to enhance global and national commitments for the health and development of children and adolescents.¹²

Key messages

• Human capital requires a foundation of health, knowledge, skills, and learning acquired from preconception to 20 years of age; healthy growth and development from conception to the second birthday are crucial

• Mortality rates before 20 years of age are important measures of the survival component of human capital; of the 8·6 million deaths before 20 years of age in 2019, more than half were stillbirths or occurred in the first month after birth

• Regional disparities are large with children in south Asia and sub-Saharan Africa having the worst chance to survive and thrive

• The Nurturing Care Framework, as adapted to extend from preconception through childhood and adolescence, conceptualises influences on the formation of human capital and identifies crucial periods for interventions