Air Pollution, Cardiovascular Disease, and Dementia

To the Editor In a recent issue, Grande et al¹ contribute to an emerging body of evidence suggesting that exposure to air pollution may increase the risk of dementia. The authors reported that elevated long-term exposure to nitrogen dioxide and fine particles is linked to an increased risk of dementia, which is aligned with prior research.² They also examined the role of cardiovascular disease (CVD) subtypes as effect modifiers and intermediates in this association, building on previous findings.³ The authors reported evidence of outcome heterogeneity by heart failure and ischemic heart disease and mediation by stroke. Evaluating effect measure modification and mediation can contribute to improved understanding of dementia causative mechanisms and prevention. Yet, there are some critical issues in this report¹ that may influence the study’s effect sizes and conclusions. Additional sensitivity analyses and discussion are strongly encouraged to assess the robustness of the estimates presented in the article.¹