“What happens in pregnancy and childhood sets us on a trajectory and determines our lifetime risk of disease,” said Prof. Shane Norris of the Department of Pediatrics, University of the Witwatersrand. Norris was speaking at a seminar presented by the STIAS DOHaD group.
DOHaD – the Developmental Origins of Health and Disease – provides a paradigm for disease causation while also highlighting personal and population-level interventions for avoiding harm and promoting health. It’s based on growing evidence that the negative consequences of early childhood insults (including during pregnancy) are related to chronic non-communicable diseases (NCDs) in later life (including type-2 diabetes, cardiovascular diseases, some cancers and mental health).
“DOHaD was initially all about foetal origins of adult health and disease,” continued Norris. “There was initial scepticism – people couldn’t fathom adult conditions having their origin in the foetal period. Now there is so much evidence that the argument is well established. Also, the evidence has highlighted that the childhood period is also important and the focus was broadened to go beyond just pregnancy.”
Norris is a member of the STIAS DOHaD group, a project which falls under the STIAS long-term theme ‘Health in Transition’. The aim is to identify studies, advocacy programmes and partnerships that can be undertaken by future DOHaD-oriented Fellows of STIAS. The group is also convening a workshop at STIAS this month, where experts from Africa and other countries will present their work and help to plan a research and implementation agenda.
“DOHaD is an umbrella terms that encompasses a wide range of disciplines,” said Prof. Abdallah Daar of the Dalla Lana School of Public Health, University of Toronto, convenor of the group.
“It’s timely to bring great minds together. We want early implementation in Africa of interventions for which there is evidence and also to seek evidence on the things we don’t know.”
“The Sustainable Development Goals (SDGs) provide us with an opportunity and energy, including potential financing, to do something more concrete and faster in relation to implementing some of the actionable outcomes of DOHaD thinking in Africa and beyond,” continued Daar. “Many of the SDGs, including #1 (eliminate poverty), #2 (eliminate hunger), #3 (good health, which mentions chronic NCDs and also mental health), #4 (quality education), # 5 (gender equity), # 6 (clean water and sanitation) and #10 (reduced inequalities) are directly relatable to DOHaD.”
Genes and environment
Research shows that the environment in which the embryo, foetus and young child grow and develop influences their health and wellbeing for life. Environmental aspects include nutrition, toxins and the age at which pregnancy occurs. These environmental exposures during early development shape the body’s responses to later challenges such as unhealthy diets, sedentary lifestyle, sleep patterns, and ongoing toxin exposure.
“Our genes have different levels of plasticity and can be switched on and off based on cues from the environment,” said Norris. “They switch to best fit the environment. If the environment changes rapidly there could be a mismatch – for example, if a person changes from a situation of undernutrition to overnutrition – and this has health consequences.”
“So rapid changes in lifestyle exacerbate the biological responses,” he continued.
Reducing the burden of NCDs requires interventions to promote healthy early development, beginning before conception, as well as interventions aimed at sustaining health in children, adolescents and adults.
But it’s not just about the babies. It’s important to improve and save the lives of mothers, especially during the perinatal period. And fathers don’t get off the hook. Current work is showing that paternal genes, unhealthy behaviours and exposure to harmful environments also have similar impacts on the next generation.
“The contribution from Africa to the field has been very small thus far,” said Norris. “We need to galvanise the research agenda to understand how to translate DOHaD for improved health on the continent.”
And Africa offers unique challenges.
“In Africa there are multiple disease burdens,” said Norris. “A pregnant woman may have several disease conditions and we need to understand the effect of this on her unborn child.”
“The challenge is also that we are looking at things that happen over people’s lifetimes,” added Prof. Peter Byass of the Umeå Centre for Global Health Research in Sweden. “Tracking this on a continent like Africa where data are scarce is difficult. Health or disease outcomes across generations are the data of interest. It’s therefore important to understand cause-of-death patterns, but in most African countries those data are not available.”
“Scaling up great implementation ideas – implementation science – is a real challenge everywhere,” added Daar.
“The dilemma right now is that, in most instances, we can’t tell people exactly what works to improve the situation,” said Andrew Macnab of the Department of Pediatrics, University of British Columbia. “Much of the science related to DOHaD is still at the population level, and has yet to be translated into specific health strategies that individuals can adopt.”
It’s also about raising awareness and educating practitioners and health system managers to implement what we know does work. Speaking specifically about blindness, Prof. Dorairajan Balasubramanian of the L V Prasad Eye Institute, Hyderabad pointed out that low-cost solutions are available to eliminate lifelong blindness in premature babies and children if the clinicians are aware of the risk and able to act to implement treatment quickly.
Better information for better choices
“Governments have a pivotal role to play,” said Macnab, “but we also have to have better-informed people who are able to take responsibility for their own health. In this context engaging children is a particularly important investment.”
“Innovative education has the potential to sow the seeds that will change the behaviour of the next generation,” he continued. “But, when working to engage youth, what you say and how you say it is central to whether stakeholders see any relevance.”
“The World Health Organization’s Health Promoting Schools model has been shown in many projects in Africa to be able to influence behavioural change in children and that beneficial effects can trickle down to communities,” he said. “However, it’s a challenge to implement this model in South Africa at present due to the current educational milieu.”
“DOHaD is a reality,” concluded Byass. “We want to understand how much it is influencing the health status of the continent and how this is changing over time. We know living conditions are changing in Africa more rapidly than anywhere else – it would be good to put data to that.”
Michelle Galloway: Part-time media officer at STIAS
Photographs: Christoff Pauw