Prenatal Exposure to Air Pollution and Risk for Attention-Deficit/hyperactivity Disorder in Children

Exposure to air pollutants during early life may impair children's neurodevelopment and increase the risk of ADHD. The study aimed to explore the association between exposure to prenatal air pollutants and ADHD in the school population from Tarragona, Spain. Data were obtained from the EPINED study, a two-phase epidemiological research involving preschool-aged (4-5 years) and school-age (10-11 years) children. The screening phase assessed ADHD symptoms in 3,727 participants, followed by a diagnostic phase with 781 children (549 without ADHD, 174 with ADHD). Multivariable regression showed that higher prenatal exposures to PM₁₀ (β-1.88; CI: 0.65-3.12), PM_coarse (β-1.25; CI: 0.52-1.98), NO₂ (β-1.11; CI: 0.56-1.66), and NO_x (β-1.29; CI: 0.66-1.91) were significantly associated with increased teacher-reported ADHD symptoms in school-age children. No significant association was observed between exposure to air pollutants and any ADHD presentation. Trimester-specific analyses revealed significant associations between prenatal exposure to air pollutants during early pregnancy and inattentive symptoms, as assessed by the Schedule for Affective Disorders and Schizophrenia for school-age children and teacher reports. In the first and second trimesters, exposure to PM_2.5, PM₁₀, PM_coarse, NO₂, and NO_x was significantly associated with increased inattention, highlighting critical windows of gestational susceptibility to air pollution and ADHD risk, with effects more pronounced in males. Our findings suggest that even modest increases in ADHD symptoms may reflect subtle neurodevelopmental effects of prenatal air pollution exposure. These results highlight early gestation as a vulnerable period and the need for further research on long-term impacts.