How the past shapes our futures: the DOHAD concepts
The Developmental Origins of Health and Disease (DOHaD) is a discipline that studies health across a life course. This perspective studies the effect of early life course decisions, opportunities, and conditions on later outcomes. There are various critical periods (preconception, infancy, adolescence) and levels (cohort, generational) that shape the life history of a person or society and the effect can be a ripple or a domino such that even small changes early in life can make large differences later on. The science of epigenetics has provided a biological basis to explain how by non-genetic influences can pass from generation to generation.
Many diseases are associated with our modern lifestyle, suggesting common risk factors for many diseases. These include unhealthy dietary patterns, reduced physical activity, altered patterns of microbial exposure, tobacco smoking, harmful use of alcohol, and other environmental pollutants. Certain behaviours, like dropping out of school or witnessing domestic abuse, can set up a chain reaction of experiences for individuals and their families that may lead to a reproduction of poverty and or a cycle of family violence. The past can significantly influence later life outcomes; not only physical health but also socioeconomic status, mental health, physical functioning, and marital patterns. This long-term view, with its recognition of cumulative advantage or disadvantage, is particularly valuable for understanding social inequality in later life and for creating effective social policy and programs.
This life course paradigm is especially
pertinent to Indigenous populations, who often are most disadvantaged even when
they live in affluent countries. Pregnancy (and pre-conceptional period) and
early childhood are critical times of risk, where many different factors can
influence development. But they are also critical times of opportunity, where
healthy lifestyle behaviours can prevent the risk of future disease.
The themed Issue focuses on DOHaD as it applies to Indigenous populations across the world. This includes a narrative review of DOHaD as it applies to Indigenous populations (McEwen et al), a report from a major national longitudinal study of Australian Indigenous children, “Footprints in time” that describes the health of Australian Indigenous children using a social and cultural lens and the next generation cohort which describes the high risk of diabetes seen in children of First Nations mothers who have diabetes themselves. Two studies have followed women from pregnancy onwards ; the Indigenous Australian pregnancy-through-to-early childhood cohort showing the effects of being born preterm or large for gestational on later obesity and the other describing the effects of stress on Aboriginal women during pregnancy and beyond. The Saskatchewan study not only being too small, but also being too large at birth can have negative health impacts in later life. The study by Hoy and Nicol shows that low birth weight and birth weight has a strong association with natural deaths. Together, this collection of studies highlight the need for more understanding of the role of DOHAD in the health of indigenous populations and the selection and implementation of interventions to improve health in the future.