BMJ Ment Health. 2025 Sep 30;28(1):e301864. doi: 10.1136/bmjment-2025-301864.
ABSTRACT
BACKGROUND: Little is known about the mechanisms underlying associations between air pollution exposure in childhood and mental health disorders in adulthood.
OBJECTIVE: To examine the prospective associations between age-10 air pollution exposure and age-18 mental health disorders and to test potential mediation by impaired cognition at age 12.
METHODS: We used longitudinal observations of 1969 members of the Environmental Risk Study who were born across England and Wales in 1994-1995. Exposure to nitrogen dioxide, nitrogen oxides (NOx) and particulate matter (PM2.5 and PM10) was modelled for residential addresses at age 10. Past-year prevalence of anxiety, depression, conduct disorder and attention-deficit/hyperactivity disorder was assessed by interview at age 18. Overall cognition (full-scale IQ) and specific domains (fluid ability, crystallised ability and working memory) were assessed at age 12. We employed binary logistic regression to examine pollution-disorder associations and generalised structural equation modelling to examine mediation via impaired cognition.
FINDINGS: Higher exposure to NOx was associated with greater odds of depression after covariate adjustment (OR=1.25, 95% CI 1.01 to 1.55). No robust associations were evident for the other pollutants or outcomes. Overall cognition (indirect effect (IE): OR=1.00, 95% CI 0.99 to 1.01) and crystallised ability (IE: OR=1.00, 95% CI 0.99 to 1.01) did not mediate the association between NOx and depression.
CONCLUSIONS: We found no evidence that impaired cognition mediated associations between childhood residential exposure to NOx and depression in early adulthood.
CLINICAL IMPLICATIONS: Policies to reduce childhood exposure to NOx may help reduce depression in early adulthood. Future research should examine alternative mechanisms.
PMID:41033691 | DOI:10.1136/bmjment-2025-301864
