Environmental exposures during early life are associated with certain molecular profiles in childhood

Our health greatly depends on the environment in which we live. In fact, 70-90% of the risk of developing a disease is determined by our exposome: a multitude of environmental factors (i.e. non-genetic factors) to which we are exposed throughout our lives.

“Exposures during early life can have pronounced effects at the molecular level that may not be clinically detectable until adulthood,” explains Martine Vrijheid, Head of the Childhood and Environment Programme. “But we know very little about how different environmental hazards may interact and what biological processes they may trigger.”

This unique catalogue can provide valuable insights into how the environment impacts our health

Vrijheid and her team set out to associate multiple chemical, outdoor, social and lifestyle exposures (92 during pregnancy and 116 when the children were 6-11 years old) with molecular profiles in the same children (DNA methylation and gene expression in blood, plasma proteins, and metabolites in serum and urine). The study included 1,301 mother-child pairs from the Human Early Life Exposome (HELIX) project, a long-term cohort study in six European countries (Spain, United Kingdom, France, Lithuania, Norway and Greece).

A gold mine of data

The analysis, made possible by the use of massive parallel computing, identified 1,170 significant associations. Exposures during pregnancy (e.g. to tobacco smoke or cadmium) were more often associated with changes in DNA methylation (which in turn modifies gene activity), while childhood exposures were associated with a wider range of signatures, particularly with metabolites in serum. The analysis also identified possible sources of exposure (for example, the children’s diet as a source of chemical pollutants).

Finally, the results provide possible disease mechanisms for six groups of exposures, including copper, tobacco smoke and indoor air quality. For example, child exposure to copper was associated with nearly 90 molecular features, including increased levels of C-reactive protein (an inflammation marker).

“The rich exposomal and molecular information available in our catalogue is a valuable resource for the scientific community to find biomarkers of exposure, identify sources of exposure, improve the understanding of disease mechanisms and, ultimately, inform public health policy,” concludes Vrijheid.

The study is part of the EU-funded ATHLETE project and the results are publicly available at https://helixomics.isglobal.org

Ruiz-Arenas C, Hernandez-Ferrer C, Vives-Usano M et al. Identification of autosomal cis expression quantitative trait methylation (cis eQTMs) in children’s blood. eLife. 2022;11:e65310 doi: 10.7554/eLife.65310

Photo: Canva