Mendelian randomization study supports the causal effects of air pollutants on cognitive function

Observational studies have linked air pollutants to cognitive impairment, though the causal relationship is yet to be firmly established. This research employs a two-sample Mendelian randomization (MR) analysis to evaluate the causal effects of exposure to PM 2.5 , PM 10 , NO 2 , and NO x on cognitive function. This study extracted 8 single nucleotide polymorphisms (SNPs) associated with PM 2.5 , 22 SNPs associated with PM 10 , 7 SNPs associated with NO 2 and 8 SNPs associated with NO x as genetic variants on European ancestry. The primary method for MR estimation utilized was inverse variance weighting (IVW). The findings indicate that exposure to PM 2.5 results in poorer performance on the Trail Making Test (beta = 0.24, 95% CI: 0.01 to 0.47, P = 0.04). Exposure to NO x is associated with a decline in fluid intelligence (beta = -0.88, 95% CI: -1.42 to -0.34, P = 0.002). Additionally, each standard deviation increase in NO x exposure is linked to a decrease in the number of correct matches (beta = -0.39, 95% CI: -0.73 to -0.05, P = 0.02) and attempted matches (beta = -0.40, 95% CI: -0.74 to -0.05, P = 0.02) on the Symbol Digit Substitution (SDS) test, and an increase in the time taken to enter a value (beta = 0.41, 95% CI: 0.06 to 0.76, P = 0.02). Furthermore, a positive association was observed between PM 10 exposure and the risk of Alzheimer's disease (OR = 2.15, 95% CI: 1.14 to 4.03, P = 0.02). This study suggests that PM 10 is causally associated with Alzheimer's disease risk. Genetically PM 2.5 and NO x exposure showed a significant association with cognitive decline in people of European origin. Air pollutants is important for developing effective prevention strategies for cognitive decline. • First study linking air pollution to multiple cognitive tests. • PM 2.5 and NO x causally linked to cognitive decline. • PM 10 causally linked to increased Alzheimer's disease risk.