ACPA are part of the new classification criteria for RA and often precede disease onset. So far dataon ACPA came from retrospective case-control studies in established RA, or from studies inrelatives from RA patients. From these studies it is known that ACPA preceding RA differs fromACPA in established RA. Moreover, the presence of ACPA increases the risk for RA in persons withjoint pain or undifferentiated RA. ACPA also predicts worse outcome in established RA. ACPA in preRA differs in isotypes, affinity and epitope recognition (together ACPA fine specificity) from ACPA inRA. At present there are no data available on ACPA characteristics in healthy individuals that willnot develop RA in the future.In the present study we want to investigate the presence and the predictive value of ACPA finespecificity in 60.000 LifeLines participants. Important data on environment, family, genes, andinflammation all are collected within LifeLines.Primary aim:Can specific characteristics of ACPA predict the development of RA; In the present study we willinvestigate the differences in fine specificity of ACPA from healthy persons versus ACPA associatedwith the development of RA in the (near) future.Secundary aims:Relation of ACPA fine specificity to environmental risk factors like smoking and genetic risk factorslike HLA-DRB1-SE.