Causal association between air pollution and functional outcome after ischemic stroke: Evidence from 2-sample MR...

Area of Science:

• Environmental Health
• Neurology
• Genetic Epidemiology

Background:

• Observational studies suggest a link between air pollution and functional outcomes post-ischemic stroke.
• Mendelian randomization (MR) offers a method to investigate causal relationships, mitigating confounding factors.

Purpose of the Study:

• To evaluate the association between genetically predicted exposure to specific air pollutants and functional outcomes following ischemic stroke.
• To apply MR methodology to assess potential causal effects of air quality on stroke recovery.

Main Methods:

• Utilized 2-sample Mendelian randomization (MR) analysis.
• Instrumental variables for air pollutants (nitrogen oxide [NOx], nitrogen dioxide [NO2], PM2.5, PM2.5-10, PM10) were derived from genome-wide association study data.
• Inverse variance-weighted (IVW) method was primary; sensitivity analyses included Cochran Q test, MR-Egger regression, and MR-PRESSO test for heterogeneity and pleiotropy.

Main Results:

• No statistically significant association was found between genetically predicted air pollutants (PM2.5, NOx, NO2, PM2.5-10, PM10) and functional outcomes after ischemic stroke.
• Results were consistent across primary and sensitivity analyses, including MR-Egger and MR-PRESSO tests.
• Further analyses, even without adjustment for stroke severity, corroborated the primary findings.

Conclusions:

• Genetically predicted exposure to common air pollutants does not appear to significantly impact functional outcomes following ischemic stroke.
• The findings suggest that air quality may not be a direct causal factor in post-stroke functional recovery.
• Further research may explore other environmental or genetic factors influencing stroke outcomes.