Higher skin autofluorescence in individuals at risk for rheumatoid arthritis: results from a large population based cohort.

Abstract
Objectives: To investigate skin autofluorescence (SAF) levels, an early marker for cardiovascular disease, in relation to the presence of anticitrullinated protein antibodies (ACPA), clinical suspect arthralgia (CSA) and rheumatoid arthritis (RA) in a large population-based cohort. 
Methods: Cross-sectional data were used from 17346 participants of the Dutch Lifelines Cohort Study, of whom baseline SAF and ACPA levels were available. The presence of CSA was determined using EULAR questions from the connective tissue disease screening questionnaire (CSQ). Individuals were divided into four groups: ACPA negative controls (n=17211), ACPA positive without CSA (n=49), ACPA positive with CSA (n=31) and defined RA (n=52). Multinomial regression was used to compare SAF levels and correct for potential confounders.
Results: SAF levels were higher in the ACPA positive with CSA group (OR 2.04, p=0.034) and the defined RA group (OR 3.10, p<0.001) compared to controls, but not in the ACPA positive without CSA group (OR 1.07, p=0.875). The difference in SAF levels remained statistically significant in the defined RA group after adjusting for age (OR 2.09, p=0.011), smoking status, renal function or HbA1c. In the ACPA positive with CSA group, the effect was found to be comparable (corrected for age: OR 2.09).
Conclusion: Our results indicate that ACPA positive individuals with CSA have elevated SAF levels which is considered as early marker for oxidative stress and developing future cardiovascular disease. Therefore, it is important to consider  cardiovascular risk management in patients diagnosed with ACPA positive CSA.