The effectiveness of balneotherapy and aquatic exercise on bone metabolism: A systematic review and meta-analysis

Objective: To systematically evaluate the effectiveness of balneotherapy and/or aquatic exercise on bone metabolism. Design: A systematic literature search was conducted from inception to January 4, 2021. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) were calculated using a fixed-effect model according to study heterogeneity. Results: Seven articles involving 467 participants were selected. Three balneotherapy studies were qualitatively integrated. The results showed that bone resorption slowed down with or without stimulation of bone formation. A pooled meta-analysis of four studies on aquatic exercise showed significant evidence for a reduction in parathyroid hormone (PTH; SMD =-0.71; 95% CI,-1.04 to-0.38; P < 0.001), and a significant increase in osteocalcin (OC; SMD = 0.60; 95% CI, 0.16 to 1.03; P = 0.007) after aquatic exercise. Conclusion: Balneotherapy and aquatic exercise had significant effects on bone metabolism, reducing bone resorption and/or increasing bone formation. This study highlights the importance of balneotherapy and aquatic exercise for bone health.