Abstract
BACKGROUND: Rheumatoid arthritis-associated autoantibodies have been associated with interstitial lung abnormalities (ILA) among community-dwelling adults. We aimed to determine whether greater numbers of positive anti-citrullinated protein antibodies (ACPAs) are associated with ILA in community-dwelling adults. METHODS: We performed a period cross-sectional study. We measured 29 ACPAs via Bio-Plex bead array (2003–2005) and ILA on full-lung CTs (2010–2012) in 868 participants enrolled in the Multi-Ethnic Study of Atherosclerosis. A positive ACPA was defined as titer > 75th percentile. We used generalized additive and logistic regression models to examine associations between number of positive ACPA and ILA and tested for effect modification by race/ethnicity. RESULTS: In an adjusted model, each 1 unit increase in log-transformed number of positive ACPA was associated with a 17% decrease in odds of ILA (OR 0.83, 95% CI 0.68–1.01). Race/ethnicity modified the association between log-transformed number of positive ACPA and ILA (interaction p-value 0.03), such that each 1 unit increase in log-transformed number of positive ACPA was associated with a 39% decrease in the adjusted odds of ILA among African American participants (OR 0.61, 95% CI 0.37–0.99) and a 42% decrease in the adjusted odds of ILA among Hispanic participants (OR 0.58, 95% CI 0.36–0.91). There was no significant association between log-transformed number of positive ACPA and ILA among White or Chinese American participants. CONCLUSIONS: In this large population-based multi-ethnic study, an expanded ACPA repertoire was associated with a lower burden of ILA on CT, especially among African American and Hispanic participants. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12931-026-03616-3.