INMA: “Exposure to mixtures of endocrine-disrupting chemicals during pregnancy is associated with higher odds of metabolic syndrome in children”

30/06/2024

New study published in Jama Network Open

The term ‘metabolic syndrome’ (MetS) describes a group of factors, such as abdominal obesity, hypertension and insulin resistance, that increase the risk of cardiovascular disease and type 2 diabetes. A new study suggests that exposure during pregnancy to a combination of endocrine disrupting chemicals (EDCs) is related to a poorer metabolic health in childhood, which can contribute to an increased risk of metabolic syndrome in adulthood. The research, led by the Barcelona Institute for Global Health (ISGlobal), a centre supported by the “la Caixa” Foundation, has been published in Jama Network Open.

EDCs interfere with the functioning of our hormonal system, growth, energy balance and metabolism and whose exposure is difficult to escape. Previous studies have already shown a link between individual exposure to some of these compounds during the prenatal phase and some of the factors that make up the metabolic syndrome, particularly obesity and blood pressure. As part of the ATHLETE project, the ISGlobal team looked at the combined impact of these substances on all metabolic syndrome factors.

The study involved 1,134 mothers and their children from six European countries (the INMA cohort from Spain, EDEN from France, RHEA from Greece, KANC from Lithuania, MOBA from Norway and BIB from the United Kingdom), all volunteers from the HELIX (Human Early Life Exposome) cohort. Prenatal exposure to 45 EDCs was analysed through blood and urine samples collected from the mothers during pregnancy or from the umbilical cord after birth.

Later, when the children were between 6 and 11 years old, they were followed up, and information on waist circumference, blood pressure, cholesterol, triglycerides and insulin levels were collected and summarized to obtain a risk index for metabolic syndrome.

Mercury, PFAS, organochlorine pesticides and PBDEs

Statistical analysis showed that mixtures of metals, perfluoroalkylated and polyfluoroalkylated substances (PFAS), organochlorine pesticides and flame retardants (or PBDEs) were associated with a higher risk of metabolic syndrome. In the case of metals, the association observed was mainly due to the effect of mercury, of which the main source of intake is large fish.

PFASs are one of the most widely used families of chemical compounds, used in pesticides, paints, non-stick pans or fast food packaging, among many other common uses. Due of their persistence, they are also known as the ‘forever chemicals’. Organochlorine pesticides, also very persistent, were already banned in Europe in the 1970s, but we are still widely exposed due to their permanence in the environment.

Different results according to sex

“We also observed that associations were stronger in girls for mixtures of PFASs and polychlorinated biphenyls (PCBs), while boys were more susceptible to exposure to parabens. Since endocrine disruptors interfere with sex steroid hormones, these differences fall within what would be expected”, explains Nuria Güil Oumrait, ISGlobal researcher and first author of the study.

“Our results suggest that exposure to widespread mixtures of endocrine disruptors during pregnancy may be associated with adverse metabolic health in both boys and girls. This association may contribute to the current increase in the prevalence of lifetime metabolic syndrome, which currently affects 25% of the adult population, with upward trends evident even among young people”, concludes Martine Vrijheid, co-director of ISGlobal’s Environment and Health over the Lifespan programme and senior author of the study.

Reference: Güil-Oumrait N, Stratakis N, Maitre L, Anguita-Ruiz A, Urquiza J, Fabbri L, Basagaña X, Heude B, Haug LS, Sakhi AK, Iszatt N, Keun HC, Wright J, Chatzi L, Vafeiadi M, Bustamante M, Grazuleviciene R, Andrušaityte S, Slama R, McEachan R, Casas M, Vrijheid M. Prenatal Exposure to Chemical Mixtures and Metabolic Syndrome Risk in Children. JAMA Netw Open. 2024 May 1;7(5):e2412040.

Link to scientific article: https://pubmed.ncbi.nlm.nih.gov/38780942/