Inflammatory cytokines mediate the common genetic and immunological background between rheumatoid arthritis and osteoporosis

IL-17 promotes the progression of RA to OP; FCRL3 regulates the immune infiltration microenvironment of RA and is a potential therapeutic target. Key Points • Genetic correlation, MR, and colocalization analyses confirm a shared genetic basis between RA and OP. • IL-17 is identified as a key inflammatory mediator driving the progression from RA to OP. • Multi-trait GWAS and integrative post-GWAS analyses uncover novel RA-specific loci and 25 immune-related risk genes. • FCRL3 regulates immune cell infiltration in RA and emerges as a potential therapeutic target for inflammation-induced bone loss.