High anti-cyclic citrullinated peptide (CCP) positivity and appendicular lean mass index (ALMI) are both strongly associated with low femoral neck bone mineral density (BMD) in patients with rheumatoid arthritis (RA), which suggests that processes specific to RA negatively affect BMD, according to the results of a cross-sectional cohort study published in Arthritis Care & Research.
The investigators sought to explore the contributions of RA characteristics, medication use, and body composition to low BMD in patients with RA. Data were collected from the Arthritis, Body Composition, and Disability Study, which enrolled 138 patients, including 82 women and 56 men. Body composition (fat, lean muscle, and BMD) was assessed by dual x-ray absorptiometry. The association between predictors and femoral neck BMD was determined via linear regression analyses.
The average disease duration of the participants was 19 years. In addition, 70% of participants were rheumatoid factor-positive and 55% had high-positive anti-CCP levels. Older age (β= -0.003; 95% CI, –0.005 to –0.001; P <.0009), high-positive anti-CCP levels (β= -0.054; 95% CI, –0.097 to –0.010; P =.016), and lower ALMI (β= 0.053; 95% CI, 0.028-0.077; P <.0001) were all independently and significantly associated with lower BMD. In addition, in patients with high-positive anti-CCP levels, increasing anti-CCP levels were associated with a negative linear trend in BMD (β= -0.011; 95% CI, -0.022 to -0.001; P =.026).
The investigators concluded that the findings of this study underscore the complicated relationship between RA disease-specific and functional factors, along with their impact on bone mass. The positive association observed between ALMI and BMD emphasizes the importance of this modifiable risk factor in patients with RA. Further research is warranted in order to identify effective ways to improve lean muscle mass in individuals with RA.
Wysham KD, Shoback DM, Imboden JB Jr, Katz PP. Association of high anti-cyclic citrullinated peptide seropositivity and lean mass index with low bone mineral density in rheumatoid arthritis [published online November 5, 2017]. Arthritis Care Res.