Particulate matter 2.5 causally increased genetic risk of autism spectrum disorder

Growing evidence suggested that particulate matter (PM) exhibit an increased risk of autism spectrum disorder (ASD). However, the causal association between PM and ASD risk remains unclear.

We performed two-sample Mendelian randomization (MR) analyses, using instrumental variables (IVs) sourced from the largest genome-wide association studies (GWAS) databases. We employed three MR methods: inverse-variance weighted (IVW), weighted median (WM), and MR-Egger, with IVW method serving as our primary MR method. Sensitivity analyses were performed to ensure the stability of these findings.

The MR results suggested that PM_2.5 increased the genetic risk of ASD (β = 2.41, OR = 11.13, 95% CI: 2.54–48.76, P < 0.01), and similar result was found for PM_2.5 absorbance (β = 1.54, OR = 4.67, 95% CI: 1.21–18.01, P = 0.03). However, no such association was found in PM₁₀ (β = 0.27, OR = 1.30, 95% CI: 0.72–2.36, P = 0.38). After adjusting for the false discovery rate (FDR) correction, our MR results remain consistent. Sensitivity analyses did not find significant heterogeneity or horizontal pleiotropy.

Our findings indicate that PM_2.5 is a potential risk factor for ASD. Effective strategies to mitigate air pollutants might lead to a reduced incidence of ASD.