Radiographic damage and its progression in early rheumatoid arthritis (RA) can be predicted by markers and regulators of bone metabolism. Studies of bone formation in RA patients measuring osteocalcin or the N-terminal telopeptide of type I procollagen (P1NP) have produced varying results, whereas measurements of bone resorption using serum or urine C-terminal crosslink of type I collagen (β-CTX) mostly show increased values. 1–3 RA patients often have elevated serum levels of the osteoclast-activating cytokine receptor activator of nuclear factor κB ligand (RANKL), as well as of osteoprotegerin, which prevents osteoclast activation. 4

We previously reported increased levels of autoantibodies and acute phase reactants in blood donors years before the onset of RA symptoms. 5 6 We now investigated whether this subtle increase of inflammation has an influence on preclinical bone metabolism and on later occurring radiographic damage.