Effects of dynamic exercise on circulating IGF-1 and IGFBP-3 levels in patients with rheumatoid arthritis or ankylosing spondylitis

This study was performed to determine the effects of short-term dynamic exercise on serum insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) levels in the patients with rheumatoid arthritis (RA) and ankylosing spondylitis (AS). Patients with RA or AS and healthy controls were recruited. Dynamic treadmill exercise therapy was accomplished for 20 min/session with all of the participants. There were five sessions per week for 2 weeks. Morning stiffness duration, body pain, Stanford health assessment questionnaire, Ritchie articular index, Bath ankylosing spondylitis disease activity index (BASDAI), and Bath ankylosing spondylitis functional index (BASFI) were evaluated in the RA and AS patients. Laboratory assessments included: erythrocyte sedimentation rate, serum C-reactive protein, IGF-1, and IGFBP-3. Clinical and laboratory assessments were recorded at baseline and during exercise treatment on days 7 and 15. Twenty patients with RA, 15 with AS, and 14 healthy controls were included in this study. The pain evaluation, Ritchie, BASDAI, and BASFI scores were significantly improved by the exercise treatment in both patient groups. The important increases were found in circulating IGF-1 in RA (p < 0.001) and AS (p = 0.001) at the end of 2 weeks. In control individuals, serum IGF-1 levels showed a significant decline in the first week (p < 0.05). No significant changes were observed on serum IGFBP-3 levels. Our data suggest that serum IGF-1 levels are increased by the dynamic exercise program in RA and AS patients. The increased IGF-1 may play an important role in the beneficial effects of dynamic exercise therapy in these patients.