Late-Onset Rheumatoid Arthritis and Air Pollution in a Multiethnic Cohort.

Area of Science:

• Environmental Health
• Rheumatology
• Epidemiology

Background:

• Rheumatoid arthritis (RA) is a chronic autoimmune disease with complex etiology.
• Ambient air pollution exposure is increasingly recognized as a potential environmental risk factor for various health conditions.
• Racial and ethnic disparities exist in RA incidence and severity.

Purpose of the Study:

• To investigate the association between ambient air pollution and the incidence of rheumatoid arthritis (RA) in a diverse elderly population.
• To explore potential differences in these associations across racial and ethnic groups.

Main Methods:

• Analysis of 42,152 participants aged 65+ from the California Multiethnic Cohort (MEC) Medicare data (2001-2018).
• Utilized multivariable Cox proportional hazards regression with time-varying air pollutant data from spatiotemporal models.
• Adjusted for demographics, neighborhood socioeconomic status, smoking, and occupational exposures.

Main Results:

• Increased RA incidence was associated with exposure to fine particulate matter (PM$_{2.5}$) and nitrogen dioxide (NO$_{2}$).
• Higher risk associations were observed in African American and Latino adults compared to Japanese American and White adults.
• The association between PM$_{2.5}$ and RA was stronger in men and individuals with high-risk occupational exposures.

Conclusions:

• Ambient air pollution, including PM and gaseous pollutants, is associated with a higher incidence of RA in adults over 65.
• These findings highlight the potential role of air pollution in exacerbating racial and ethnic disparities in RA risk.
• Further research is needed to fully understand air pollution's contribution to RA disparities.