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Our improved understanding of how experience-based brain development in the early years of life affects neurobiological pathways that affect health (physical and mental), learning and behaviour throughout life has led to some model countries developing integrated early child development (ECD) and parenting programs linked to education and health (1). The adult socioeconomic gradients in health, learning and behaviour reflect the equity in early human development in a society (1,2).
The World Health Organization’s recent report (2) on the social determinants of health, in the chapter on “Equity from the Start”, states that “the science of ECD shows that brain development is highly sensitive to external influences in early childhood starting in-utero with life-long effects”. To achieve equity in health and learning, the Commission recommended equity in human development from the prenatal period. To do this, the Commission attempted to put science into action by recommending that “governments build universal coverage of a comprehensive package of quality ECD programs and services for children, mothers, and other caregivers regardless of ability to pay”.
The purpose of the meeting of the Council for Early Child Development in Sackville, New Brunswick, was to review how the different regions of Canada were putting the science of early neurobiological development into action to enhance ECD.
We now have a better understanding of how experience during early development (conception to age six years) affects the development of the architecture and function of the brain. The brain is sculpted by lifetime experiences. A very important time is in utero and during the first years of life. Experience is the stimuli from the various sensing pathways encountered prenatal, postnatal and during the early stages of development. The stimuli that affect the development of the brain and its functions include sound, touch, vision, smell, food, drugs, injury and disease. There are qualitative differences in the effects of stimulation at different stages of development.
All the neurons in an individual’s brain have the same genetic code. The stimuli that enter the brain affect the regulation and function of genes (DNA). This makes it possible for the neurons in the brain to differentiate in early life for diverse functions such as vision, hearing, touch, etc. Two of the biological programs that affect the function of normal DNA and messenger RNA are epigenetics and microRNAs (3). Thus, identical twins have the same DNA in their neurons, but given their different experiences in early life, they will have significant variation in their behaviour as adults. This means that although they have the same genotype (DNA), there is a difference in their phenotype (gene function).
Higher levels of brain circuits depend on precise stimulation from lower level circuits to accomplish their function. The neural pathways for vision and hearing are important for the development of language, and these pathways are usually well established by the age of three years (1,4). This is considered to be a critical period. The function of these pathways is stimulated by the amount of language exposure in the early years. The function of these language neural pathways is important for the development of cognitive function in later development.
We now understand the effects of early stimulation on the architecture and function of the brain that affect physical and mental health later in life (1,4). Among the health problems in adult life affected by development of the neurobiological pathways in early development (including in utero) are coronary artery disease, high blood pressure, type 2 diabetes, and some mental health and behaviour problems (1,4,5). These findings come from studies of birth cohorts, retrospective studies of the life course with respect to health problems, learning and behaviour, and special interventions to enhance early development. The California Kaiser Permanente program working with the Centre for Chronic Disease Prevention and Health Promotion in Atlanta, Georgia, has examined the relationship between health problems in adult life and ECD (6). This retrospective study has shown that chronic diseases of adult life (obesity, heart disease, type 2 diabetes, depression and other mental health disorders) are related to the quality of ECD. This study, as well as other work, has confirmed the conclusion from Barker’s study (7) of men in Hertfordshire, United Kingdom, showing the relationship between prenatal growth and death from coronary artery disease in adult life.
Studies (8) of children from Romanian orphanages adopted after eight months or longer in the orphanages into middle-class homes in the United Kingdom, Canada and the United States show at 11 years of age, in contrast to children adopted within three to four months after birth, abnormal brain development, social and cognitive problems, and vulnerability to behaviour problems such as attention-deficit hyperactivity disorder, aggression and quasi-autism. A study (9) on the development of children from the Romanian orphanages placed in foster parenting versus children left in the orphanages has recently been reported. The children placed early in foster care showed good early development, while the children who were not put into foster care until after the age of two years showed poor development.
Ludwig and Sawhill (10), after reviewing all the evidence regarding ECD, came to the conclusion that ECD programs should begin early, frequently and effectively. Cuba is one country (4) that has put in place ECD programs, beginning during pregnancy, that involved frequent effective interaction with mothers and their children. In the first United Nations Educational, Scientific and Cultural Organization study of language in Latin American countries (4), the Cuban mean values were two standard deviations better than other Latin American countries.
At the meeting in Sackville, much of this evidence was reviewed and the delegates discussed the objective of the meeting, “Putting Science into Action”. We considered other cultures that have worked at putting the neurobiological science of ECD into action. This included Scandinavian countries (Sweden), Cuba and some other Latin American countries such as Chile, Mexico and southern Brazil. In all of these countries, they have established or are trying to establish universal ECD centres involving parents.
These centres involving parents meet many of the requirements for good ECD set out in Hrdy’s book Mothers and Others: The Evolutionary Origins of Mutual Understanding (11). In her book, she reviews how human societies (others) at different stages of development have been able to support pregnant mothers and mothers with young children.
Today, we know how early development affects performance in the school system, behaviour, and the risks for physical and mental health problems in adult life. The challenge for our societies is to be able to integrate the new knowledge about how early neurobiological development affects health, behaviour and education into an integrated program structure in our communities that supports quality ECD for families with young children. To meet this challenge, we will require integration of government programs (health, education, social services) and support from all sectors of society including medicine and public health. Many family physicians and general paediatricians can and do provide advice and support for families (prenatal and postnatal). Developmental paediatrics is a subspecialty group in paediatrics that can provide therapeutic guidance and support for mothers with identified problems with young children. It is important that graduates from medical and nursing schools (including public health) appreciate the importance of early development on the structure and function of the brain, and the effects on health, learning and behaviour throughout the life course.
Today, Canada has a broader understanding of developmental neurobiology and ECD, and the effects on health, learning and behaviour throughout the life cycle, but has not yet achieved a universal integrated ECD program for all families with young children, nor the integrated training opportunities to realize it (1).