Foot Dysfunction and Its Associations with Kinesiophobia and Concern About Falling in Adults with Fibromyalgia Syndrome: A Cross-Sectional Study

Background/Objectives: Foot problems are common in fibromyalgia syndrome (FMS) and may be related to pain, kinesiophobia, and concern about falling. This study examined associations between foot function, kinesiophobia, and concern about falling in adults with FMS and identified factors independently associated with worse foot function. Methods: Adults with clinically diagnosed FMS were assessed between December 2024 and April 2025 in this cross-sectional study. Foot function was evaluated using the Foot Function Index (FFI), kinesiophobia with the Tampa Scale for Kinesiophobia-11 (TSK-11), and concern about falling with the Falls Efficacy Scale–International (FES-I). Multivariable linear regression identified factors independently associated with total FFI score. Results: Among 444 participants, 95.3% were women. The mean FFI score was 52.28 ± 23.24/100, with pain showing the greatest impairment. The mean TSK-11 and FES-I scores were 29.21 ± 7.91 and 39.73 ± 12.41, respectively. FFI scores were associated with both TSK-11 and FES-I scores in bivariate analyses (p < 0.001). In multivariable analysis (adjusted R2 = 0.366), older age was associated with lower FFI scores, whereas higher BMI, smoking history, rheumatoid arthritis, and higher FES-I scores were independently associated with worse foot function. Conclusions: Foot dysfunction in FMS was associated with kinesiophobia and concern about falling, but only concern about falling remained independently associated after adjustment. Higher BMI, smoking history, and rheumatoid arthritis were also associated with worse foot function. Assessment of concern about falling may provide complementary information when evaluating foot-related functional impairment in individuals with FMS.