Assessment of anti-malondialdehyde-acetaldehyde antibody frequencies in rheumatoid arthritis with new data from two independent cohorts, meta-analysis, and meta-regression.

"Declarations Ethics approval and consent to participateAll participants gave their written informed consent. The study and sample collections were approved by the Autonomous Research Ethics Committee of Galicia (Ref. 2014/387 and 2017/514) and the Hospital Clinic of Barcelona Ethics Committee (approval number 2017/0679). We conducted all protocols and methods according to the relevant guidelines (Declaration of Helsinki, the Belmont Report, and the Spanish Law of Biomedical Research no. 14/2007). Consent for publicationNot applicable. Competing interestsThe authors declare no competing interests. Competing interests The authors declare no competing interests."

"Funding The research done in Santiago was funded by Instituto de Salud Carlos III through the projects PI20/01268, PI17/01606 and RD21/0002/0003, co-funded by the European Union. L.R.-M. was supported by Xunta de Galicia (Spain) through a Gain pre-doctoral fellowship (IN606A-2017/015). The research in Barcelona was funded by the Spanish Ministry of Economy, Industry and Competitiveness and the European Regional Development Fund (Grant PID2021-122216OB-I00)."