Childhood outdoor air pollution exposure across multiple microenvironments and metabolic syndrome: A HELIX cohort analysis.

BACKGROUND

There is growing evidence for an association between air pollution exposure and cardiometabolic morbidity and mortality. However, research on the association between air pollution exposure and metabolic syndrome (MetS) risk during childhood is scarce.

OBJECTIVE

To investigate the associations between childhood air pollution exposure in various microenvironments (home, school, commute) and their cardiometabolic risk score.

METHODS

This population-based observational cohort study utilized data from the Human Early Life Exposome (HELIX) study, based in six European countries. A total of 1147 children aged 6-11 years were included. Land-use regression models (LUR) were used to estimate PM2.5 and NO2 concentrations in different microenvironments, one year before the outcome assessment. A composite MetS risk score was calculated using z-scores of waist circumference, triglycerides, high-density lipoprotein cholesterol, systolic and diastolic blood pressure, and insulin levels. Multiple linear regression models were used to determine the association between air pollution exposure in each microenvironment and MetS risk score.

RESULTS

Children had an average MetS risk score of -0.05 (SD = 2.29). When adjusting for all covariates, an IQR increase of both pollutants at home (IQR PM2.5: 3.15 μg/m3; NO2: 18.65 μg/m3) and at school (IQR: PM2.5: 3.02 μg/m3; NO2: 17.41 μg/m3) was significantly associated with an increase in the MetS risk score (home: PM2.5 β = 0.29; 95% CI, 0.03 to 0.55, NO2 β = 0.42; 95% CI, 0.05 to 0.79; school: PM2.5 β = 0.36; 95% CI, 0.08 to 0.65, NO2 β = 0.60; 95% CI, 0.21 to 0.99). Air pollution during commuting was not statistically significantly associated with MetS.

CONCLUSIONS

This multi-country cohort study indicates that childhood exposure to air pollution-both at home and at school-is associated with an increased risk of metabolic syndrome. Given the widespread nature of outdoor air pollution globally and the long-term health impacts of metabolic syndrome, these findings have significant public health implications.