Air pollution exposure and mental health disorders in Catalonia: A population-based cross-sectional study.

INTRODUCTION

Air pollution is a global health threat increasingly linked to mental disorders. Exposure to particulate matter (PM10), nitrogen dioxide (NO2), and ozone (O3) has been linked to higher risk of these conditions. Evidence is strongest for NO2, while findings for PM10 and O3 remain inconsistent, particularly in Southern Europe.

METHODS

We conducted a cross-sectional study geolinking 2019 mental health diagnoses from the PADRIS-PRESTO cohort (n=1,415,944) with air pollution data from 30 health districts in Catalonia, Spain. Annual mean concentrations of NO2, O3, and PM10 were estimated. Logistic regression models, adjusted for age, sex, socioeconomic status, and health district, examined associations between pollutant exposure tertiles and the prevalence of major depressive disorder (MDD), anxiety disorder (AD), bipolar disorder, schizophrenia (SCZ), attention deficit hyperactivity disorder (ADHD), and autism spectrum disorder (ASD).

RESULTS

NO2 exposure showed the strongest associations, including a moderate effect for ADHD (OR=2.04, 95%CI: 1.94-2.15) and small positive associations with ASD, SCZ, and AD (OR range: 1.27-1.31). O3 demonstrated a small positive association with ADHD (OR=1.41, 95%CI: 1.36-1.46) but showed no substantive associations with other disorders. PM10 showed mostly null or inverse associations, including a small inverse association with ADHD (OR=0.76, 95%CI: 0.73-0.79).

CONCLUSIONS

This large population-based study found consistent associations between NO2 exposure and neurodevelopmental and psychotic disorders, whereas O3 and PM10 showed weaker or inconsistent relationships. These findings highlight the need for longitudinal research to clarify causality.