Although the subgroups became small (n = 107 and n = 88 respectively), the effect size of the association between BMI and MRI-detected inflammation remained unchanged (respectively β = 0.97, p = 0.071 and β = 0.97, p = 0.12 for ACPA-positive RA and ACPA-negative RA in the univariable analyses and respectively β = 0.97, p = 0.097 and β = 0.96, p = 0.011 for the analyses adjusted for age and gender). Here, PRTN3 is linked to rheumatoid arthritis.