A University of Chicago Nobel Laureate in economics, RW Fogel, and a Dutch economist, JW Drukker, found that as the wealth of Western countries improved following the Industrial Revolution, life expectancy increased and the mean height of their populations improved (1,2). Since height is a product of genes and nutrition, they concluded that improved health was related to improved socioenvironments and better nutrition of children, not improvements in health care. Today, the health of populations in developed countries is a socioeconomic gradient. These health gradients (3) are linear, which means that whatever the socioeconomic factors influencing health today are, they affect everyone in society, including the wealthiest. The effect, however, is greatest on the poorest members of society. The Canadian Institute for Advanced Research’s (CIAR) population health program led by Robert Evans (University of British Columbia [Vancouver, British Columbia]) examined the factors contributing to the health gradients in Canada and other countries. They concluded that in the United Kingdom, Canada and the United States (US), the major factor contributing to inequities in health was more than poverty and a lack of health care (3). Hertzman et al (4) – members of the CIAR’s population health program – proposed that the socioeconomic conditions in early life affected adult health (physical and mental) throughout life. They and others suggested that the development of the brain and related biological pathways in early life were important factors. This led to the hypothesis that if the socioeconomic gradient in health was influenced by brain and biological pathway development in the early years, it was possible that there were similar socioeconomic gradients in education and behaviour (5). The CIAR established a program in human development to explore the concept. The scientists in this program found that the socioeconomic gradients in literacy, numeracy and behaviour were similar to the health gradients (6). They suggested that the effect of experience in early life on the development of the architecture and function of the brain was important in contributing to inequities in health and education. In 2002, the CIAR established a new program, ‘Experience-based Brain and Biological Development’ to study how genes and experience shape brain development that influences health, learning and behaviour trajectories throughout life.
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