Loutan L, et al. - First-degree relatives of patients with rheumatoid arthritis (FDR-RA) were examined for periodontal status. In addition, correlation with the presence of anti-citrullinated protein antibodies (ACPAs) was investigated. In a nested case–control study of FDR-RA with no diagnosis of RA at enrolment, 34 ACPA-positive (ACPA+) and 65 ACPA-negative (ACPA−) subjects were investigated regarding gingival index, plaque index, probing depth (PD), bleeding on probing (BOP) and clinical attachment level (CAL). ACPA+ individuals displayed significantly higher mean, PD, BOP, CAL and number of sites per person with PD > 4 mm and BOP compared to the ACPA- group. Moderate (44.1%) to severe (47.1%) periodontitis was noted in ACPA+ subjects vs mainly mild (30.8%) and moderate (27%) periodontitis in ACPA- subjects. Multivariable analyses revealed the significant and independent association of ACPA status and age with periodontal conditions.