Background Rheumatoid factor (RF), anti-cyclic citrullinated peptide antibodies (anti-CCP) and C-reactive protein (CRP) are known serum biomarkers of inflammatory arthritis (IA). They have a potential role in the prediction of incident rheumatoid arthritis (RA), particularly in high risk groups such as participants in the PRe-clinical EValuation of Novel Targets in RA (PREVeNT RA) study, a register of first degree relatives (FDRs) of patients with RA.
Objectives To assess the associations of RF, anti-CCP and CRP levels with lifestyle risk factors for IA from an established risk score .
Methods FDRs of patients with established RA are being recruited from across the United Kingdom. FDRs are free of IA and >30 years old at time of recruitment. Following informed consent, participants complete an online questionnaire to ascertain lifestyle factors potentially associated with risk of RA and provide a blood sample for central storage and analysis. For this study, we measured RF (normal ≤20 IU/ml), anti-CCP (normal ≤7 U/ml) and high sensitivity (hs) CRP (normal ≤5 mg/l) on FDRs recruited up to November 2014. Associations between these biomarkers and current smoking status, alcohol intake (units/week), body mass index (BMI, kg/m2 – derived from self-reported height and weight) and self-reported diabetes were assessed with Fisher's exact or Mann-Whitney tests, then adjusted for age and sex with multiple logistic or linear regression.
Results Complete serum biomarker and lifestyle risk factor data were available for 293 participants: 220 (75%) were female, median age at recruitment was 51 (IQR 41-62) years. 14 participants (4%) were RF positive, 4 (1%) were anti-CCP positive and 56 (19%) had an elevated hsCRP. 20 (7%) were current smokers, 10 (3%) reported being diabetic, median alcohol intake was 5 units/week (IQR 1-12) and median BMI was 25.3 kg/m2 (IQR 22.4-28.7), with 61 (21%) obese (BMI ≥30 kg/m2). RF positive participants were more likely to be current smokers (p=0.01; adjusted OR 6.21, 95% CI (1.72, 22.43)). Elevated CRP was associated with higher BMI (p<0.001), with a difference in adjusted means of 3.85 kg/m2 (95% CI (2.40, 5.30)), and subjects with an elevated CRP were also more likely to report being diabetic (p=0.004; adjusted OR 6.15, 95% CI (1.63, 23.21)). We found no association between these serological markers and alcohol consumption.
Conclusions In this FDR cohort several lifestyle factors associated with future onset of IA were also associated with biomarkers of serological risk and low-grade inflammation. These initial results suggest that early targeting of “at risk” lifestyle factors may, at a population level, reduce future risk of RA onset.
Lahiri et al. Ann Rheum Dis 2014; 73: 219
Disclosure of Interest None declared