Three decades ago, Martine Vrijheid, a professor who was investigating the prevalence of birth defects near hazardous waste sites across Europe as part of her doctoral work, discovered that there was, in fact, an increased risk near dumpsters.
Their study, carried out at the London School of Hygiene and Tropical Medicine in the United Kingdom, raised more questions.
Focus on children
“One of the big questions I was asked when we published these results was: “What would you do if you were pregnant?” said Vrijheid, a Dutch woman who is now a professor of environmental and child health at the Barcelona Institute for Global Health in Spain. “I couldn’t answer that question and thought we needed much more accurate data to provide better recommendations to women during pregnancy.”
Since then, Vrijheid has focused on how the environment in which children grow up can harm their health.
The combination of environmental influences and the way the body reacts to them is called an exposome. This combination takes into account what people eat and do, where they live and work and how they interact with the physical environment around them.
It includes everything from exposure to toxic chemicals to climate change. The environment is responsible for around 70% of the burden of chronic diseases in people, with air pollution caused by fossil fuels burned in factories, power plants, cars and buildings being one of the main causes.
For example, a third of childhood asthma cases in Europe can be attributed to polluted airaccording to the Barcelona Institute for Global Health, also known as ISGlobal.
“We know that for a large proportion of our non-communicable or chronic diseases, there are preventable causes in the environment,” said Vrijheid.
Vrijheid coordinates a research project that has received EU funding to quantify how the exposome affects the health of people in Europe during their first 20 years of life. Called ATHLETE, the five-year project runs until the end of 2024.
The ATHLETE project focuses on young people in order to reduce their overall chances of getting sick.
“It’s much more effective to start prevention in children or pregnancy than to address risk factors when people are older and already on their way to getting sick,” Vrijheid said. “Everything that happens in those early years can have consequences later in life.”
Take, for example, the growth of fetal organs. Exposure to certain chemicals during pregnancy can impede organ development.
Researchers use blood, urine and stool samples to detect biological markers, such as metabolites, which are molecules necessary for the normal functioning of cells. The goal is to connect the dots between environmental influences and a child’s health.
According to Vrijheid, the project has already found that exposure to pollutants early in life can create changes in biological markers in otherwise healthy children.
For example, childhood copper exposure has been linked to a marker of inflammation. Plausible disease mechanisms have also been found for other pollutants, including tobacco smoke and parabens, which are chemicals used as preservatives in cosmetics.
“Even if children don’t yet show any symptoms, if we can see that there are changes in their everyday genetics – or their protein profiles – that could tell us something about their future risk of disease,” said Vrijheid.
The overall goal of ATHLETE is to accumulate data and make information available to researchers.
Through several studies, the project will lead to guidance on priority actions to monitor and limit exposure to pollutants. Part of this work includes developing a guidance “toolkit” for decision-makers and communities.
Depending on the results of the study, Vrijheid said that recommendations for future policies may also emerge.
ATHLETE is one of nine research projects seeking to make advances in this field, within the scope of the European Human Exposome Network, or EHEN, the largest project of its kind worldwide, with 24 countries.
The exposome approach is not limited to treating environmental pollutants one by one, it seeks to address them as a whole, based on a clearer picture of interconnections.
As part of the ATHLETE project, a study carried out in France is evaluating whether changes in women’s personal hygiene products can affect exposure to chemical substances, such as phthalates, which interfere with the hormonal system – so-called endocrine disruptors.
In total, 90 female volunteers, aged between 18 and 30, are replacing commonly used cosmetics with alternatives for five days. With the help of urine samples collected before and after the test, the study aims to demonstrate that reducing or changing the use of personal hygiene items can reduce the presence of chemical substances in the body.
In another example, ATHLETE is examining the number of chemicals present in pesticides, food packaging and other products that are part of everyday life in Europe.
“We hope that the exposome framework will help provide evidence about clusters of risk factors that can be addressed at the same time – for example, by addressing mixtures of chemicals rather than individual regulation,” said Vrijheid.
Another of the EHEN projects is EXPANSE, funded by the EU, which focuses on urban environments, as the majority of people in Europe live there.
According to the project, by the end of the decade, more than 80% of the European population will live in and interact with an urban environment.
“Cities or urban environments are extremely important for human health,” said Roel Vermeulen, who leads the EXPANSE project and is professor of environmental epidemiology at Utrecht University in the Netherlands.
Like ATHLETE, Vermeulen’s project began in January 2020 and is expected to run until the end of 2024.
His team has been mapping the entire urban environment in Europe to gain a better understanding of the wide range of factors – from air pollution to food – that people are exposed to.
Researchers use health data from across the EU, census information covering around 55 million people, and specific groups of adults and children totaling around 2 million.
Additionally, the team is providing people with sensors to measure exposure to environmental pollutants and monitor physical activity.
In total, 4,000 people were selected for this exercise from “urban labs” in Greece, Italy, the Netherlands, Poland and Switzerland.
“The EXPANSE project will be able to provide advice on how to make neighborhoods healthier,” said Vermeulen.
The project’s focus extends to the internal exposome: measuring levels of chemicals including flame retardants, pesticides and persistent pollutants in the body.
This allows the team to examine people who develop a disease like diabetes later in life and look for chemical differences from healthy people.
“We have their blood samples 10 years before they developed the disease and we analyze what is different in the blood between these two populations,” Vermeulen said.
Part of what motivates him is his life among the cobbled streets and canals of Utrecht, especially the differences in people’s health depending on their specific neighborhood.
Vermeulen said that residents of the healthiest neighborhood enjoy 12 more years of good health than residents elsewhere in the city.
Understanding the exposome will facilitate the elimination of these types of discrepancies.
“The zip code is more important than the genetic code,” he said. “We need a global effort to understand environmental exposures and to effectively create meaningful interventions to stop non-communicable diseases.”
The research in this article was funded by the EU.
This article was originally published in Horizon, the EU’s Research and Innovation Magazine.