Pain mediates the association between physical activity and the impact of fibromyalgia on daily function

This study quantified the association between recreational physical activity and daily function in women with fibromyalgia, and determined if this association is mediated by symptoms of pain, depression, or body mass. Twenty-three women diagnosed with fibromyalgia participated in an observational survey study. Recreational physical activity and the impact of fibromyalgia on daily function were assessed using the sport and leisure time physical activity subscales of the Baecke Physical Activity Questionnaire (BPAQ) and the Fibromyalgia Impact Questionnaire (FIQ), respectively. Potential mediators of the association between physical activity and daily function were assessed using the Visual Analogue Scale for pain intensity (VAS-Pain), the Beck Depression Inventory (BDI), and body mass index (BMI). BPAQ was inversely associated with FIQ (R (2) = 0.20) and VAS-Pain (R (2) = 0.39). VAS-Pain was positively associated with FIQ (R (2) = 0.23). The inverse association between BPAQ and FIQ was no longer significant after controlling for VAS-Pain. BDI was positively associated with FIQ (R (2) = 0.37), whereas BMI was not. BPAQ was not significantly associated with either BDI or BMI. These results indicate that the intensity of musculoskeletal pain, rather than depressive symptoms or body mass, mediates the association between physical activity and daily function among women with fibromyalgia.