There was no association between RA PRSs and plasma interleukin 6 (β, 0.004; 95% CI, −0.03 to 0.03; P = .81; R2 < 0.001) or plasma C-reactive protein (β, 0.001; 95% CI, −0.03 to 0.03; P = .96; R2 < 0.001) at age 9 years (mean [SD] age at measurement, 9.9 [0.3] years). Here, CRP is linked to rheumatoid arthritis.