Causal relationships between air pollution and common autoimmune diseases: a two-sample Mendelian randomization study

Area of Science:

• Environmental Epidemiology
• Genetic Epidemiology
• Autoimmune Diseases Research

Background:

• Air pollution is a known risk factor for autoimmune diseases (ADs).
• The precise genetic causality between air pollutants and ADs remains unclear.
• Understanding these links is crucial for public health interventions.

Purpose of the Study:

• To investigate the causal relationships between common air pollutants and specific ADs using Mendelian randomization (MR).
• To explore the mediating roles of risk factors like BMI and smoking in the air pollution-ADs pathway.
• To provide evidence for air quality improvement as a preventative strategy for ADs.

Main Methods:

• Utilized aggregated data from genome-wide association studies (GWAS) for 5 common air pollutants.
• Employed single nucleotide polymorphisms (SNPs) as instrumental variables.
• Applied inverse variance weighted (IVW) method for primary analysis and two-step MR for mediation analysis.

Main Results:

• Nitrogen oxides showed a positive causal association with rheumatoid arthritis (RA), Sjogren's syndrome (SS), and systemic lupus erythematosus.
• PM2.5 and PM10 were identified as risk factors for ulcerative colitis and psoriasis, respectively.
• A negative causal link was observed between PM2.5-10 and SS; BMI and smoking mediated effects on RA.

Conclusions:

• This MR study provides robust evidence for causal links between specific air pollutants and ADs.
• Findings suggest that reducing air pollution exposure could be a viable strategy for ADs prevention.
• Further research into mediating factors can refine targeted public health strategies.