Exposing the exposome

Tuesday, 22 September, 2015
We know a lot about the human genome and the role genes play in disease. But environmental factors could play an even more important role than genetics. EU-funded researchers are helping to put together a so-called exposome to characterise the complex environmental exposure mixtures linked to disease.

“Up until now, many studies have looked at one type of exposure and one health outcome – for example, measuring one chemical or one pesticide and looking at its effect on health,” says Martine Vrijheid, who coordinates the HELIX project on behalf of the Spanish Centre for Research in Environmental Epidemiology (CREAL) in Barcelona. “We are trying to get a more complete picture of how these exposures occur together and interact to influence our risk of disease.”

The consortium decided to focus on early life, as this is a very critical period for disease development. Anything that happens during pregnancy or the first few years after birth can have a lifelong impact.

HELIX collected information from pregnant mothers and children on chemical and physical exposures to persistent and non-persistent organic chemicals, metals, pesticides, environmental tobacco smoke, water contaminants, air pollutants, noise, ultraviolet (UV) radiation and contact with green spaces.

Wearing a backpack for science

The largest share of the data comes from six existing prospective birth cohort studies involving 32 000 mother-child pairs in six European countries, combined with biomarkers. The mothers and their children have been followed for nearly 10 years now, since pregnancy. For a subset of 1 200 of these pairs – 200 in every country – the project team collected additional biomarker data.

The children in these cohorts had to wear a backpack containing different sensors and monitors for one week at a time in different seasons. The devices measured a range of specific pollutants and exposures. In addition, the mothers had to make sure that the children collected their urine every day for a week.

“At the same time, the children carried smart phones with GPS trackers that detected where they were at a given point in time,” Vrijheid explains. “They also carried accelerometers, i.e. movement sensors, to see how much the child moved and to monitor the child’s physical activity. These are some very new methods we were using to get a very complete picture of environments of exposure.”

This means that the children had to participate actively, and usually they were very motivated, Vrijheid confirms. The fieldwork was quite intensive, since the HELIX team was trying to gather data on so many different factors.

Identifying high-risk groups: towards targeted preventative strategies

A little over two and a half years into the project, the fieldwork has now been completed, and processing and analysing of the data has begun.

For the health effects of the different exposures, the researchers are looking at three main areas:

  • neurodevelopment, which will have an impact on the children’s cognitive functioning and potential behavioural problems;
  • respiratory health, including asthma, rhinitis, and several allergic outcomes – asthma is still a major childhood disease;
  • the children’s growth and potential obesity.

All three of these areas are crucial for the development of disease in adulthood, while there is increasing evidence that obesity in childhood, for instance, can lead to cardiovascular problems later in adulthood.

“Through this, we will be able to identify high-risk, vulnerable groups more easily,” Vrijheid explains. “We will be able to say: if you are exposed to air pollution and noise at the same time, then your risk of developing a disease will increase by this much. This way, we can come up with better targeted preventative strategies.”

Rean an article in Horizon magazine

The Human Early-Life Exposome – novel tools for integrating early-life environmental exposures and child health across Europe
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