Differential Association of Inflammation With Pain and Physical Function in Knee Osteoarthritis by Race Focusing on Non-Hispanic Whites and Asian Americans: Pilot Study in Florida

Background: The current body of work has not yet addressed the potential racial differences in the relationship between systemic inflammation and knee osteoarthritis (OA) symptoms, including pain and physical function. Objective: This pilot study aimed to investigate this association specifically among non-Hispanic Whites and Asian Americans. Methods: We cross-sectionally analyzed 40 community-dwelling participants aged 50-70 years with self-reported knee OA pain, including 20 non-Hispanic Whites and 20 Asian Americans. Knee OA symptoms were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and physical function subscales. The serum levels of C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and interleukin-10, as systemic inflammatory markers, were measured. Univariate and multivariable analyses, using stepwise linear regression models, were conducted to examine the correlation between these inflammatory markers and OA symptoms, with systematic adjustment for age. Results: In non-Hispanic Whites, the above inflammatory markers did not correlate with knee pain or physical function. In Asian Americans, bivariate analyses revealed that CRP and TNF-α levels were associated with worse WOMAC pain scores (r=1.325, P=.041; and r=2.418, P=.036, respectively), and CRP levels were also linked to worse WOMAC physical function scores (r=4.950, P=.035). Multivariate analyses confirmed the association of CRP levels with both worse WOMAC pain (β=1.328, P=.046) and physical function (β=4.974, P=.034) scores in Asian Americans. Conclusions: CRP may be a clinically relevant marker for knee OA symptoms, specifically in Asian Americans; however, caution is warranted owing to the exploratory nature of this study. Future research is set to benefit from leveraging a larger sample, incorporating additional inflammatory markers, and including racially diverse samples to validate and augment these findings.