Childhood exposure to air pollution linked to higher metabolic syndrome risk, suggests study

Air pollution is a major environmental risk factor for health and has been linked to a wide range of adverse health outcomes in adults, including cardiovascular disease and metabolic syndrome. Children are particularly vulnerable because their organs and immune systems are still developing, they breathe more air relative to their body weight, and they tend to spend more time outdoors. Metabolic syndrome refers to a cluster of risk factors, including abdominal obesity, high blood pressure, abnormal blood sugar and dyslipidaemia, that can increase the risk of type 2 diabetes and heart disease later in life.

To investigate this, researchers analysed data from 1,147 children aged 6 to 11 years from France, Greece, Lithuania, Norway, Spain, and the United Kingdom who were followed up with between 2013 and 2016 within the HELIX project. “We estimated exposure to PM2.5 and NO2 at home, school and during commuting, and examined its relationship with a metabolic syndrome risk score,” says Anne van Rooijen Korving, researcher at ISGlobal and first author of the study.

Using validated air pollution models based on residential, school and commuting environments, the team estimated annual exposure to both pollutants during the year prior to clinical assessment. Associations with metabolic syndrome risk were examined using multivariable regression models, and metabolic syndrome risk was calculated using a previously validated score based on waist circumference, blood pressure, blood lipids and insulin levels, following International Diabetes Federation criteria.

Stronger associations at school than at home

Air pollution was more strongly associated with metabolic syndrome risk at school than at home, suggesting that children may be particularly vulnerable in the school environment. Although pollution levels at home and at school were highly correlated (with annual PM2.5 and NO2 concentrations consistently exceeding World Health Organization guidelines), susceptibility appears to be greater at school. Previous research indicates that higher levels of physical activity at school increase breathing rates, which could amplify the adverse effects of pollution exposure. Conversely, no associations were found between exposure on commuting routes and metabolic syndrome risk. Similarly, no associations were observed for short-term exposure in the days or week before clinical assessment, supporting the idea that metabolic changes develop gradually over time rather than in response to acute exposure.

Potential biological mechanisms and public health implications

Several biological mechanisms may explain these findings. Air pollution exposure has been linked to systemic inflammation, oxidative stress, and disruptions in lipid metabolism, glucose regulation and blood pressure control all processes involved in the development of metabolic syndrome.

“Given the widespread exposure to air pollution and the long-term health consequences of metabolic syndrome, these findings have important public health implications,” says Martine Vrijheid, Director of ISGlobal's Environment and Health over the Lifecourse programme. “Our results reinforce the need to continue reducing air pollution levels to protect children’s cardiometabolic health.”

Reference:

Anne van Rooijen Korving, Parisa Montazeri, Léa Maitre, Sandra Marquez, Jose Urquiza, Nuria Güil-Oumrait, Antònia Valentín, Regina Grazuleviciene, Kristine Bjerve Gützkow, Johanna Lepeule, Rosemary R.C. McEachan, Bente Oftedal, Euripides G. Stephanou, John Wright, Wen Lun Yuan, Martine Vrijheid, Childhood outdoor air pollution exposure across multiple microenvironments and metabolic syndrome: A HELIX cohort analysis, Environmental Research, https://doi.org/10.1016/j.envres.2026.124892.