Effect of Aerobic Exercise on Markers of Bone Metabolism of Overweight and Obese Patients With Chronic Kidney Disease

Abstract

The aim of the study was to investigate the effect of aerobic exercise on markers of bone metabolism in overweight and obese nondialysis-dependent patients with chronic kidney disease. This is a post-hoc study with 39 sedentary patients (55.5±8.3years, body mass index 31.2±4.4kg/m2, estimated glomerular filtration rate 26.9±11.7mL/minute) who were randomly assigned to the aerobic exercise group (n=24) or the control group (n=15). The aerobic training (walking) was prescribed according to ventilatory threshold and was performed 3 times per week during 24weeks. Carboxylated and undercarboxylated osteocalcin (GLA and GLU), sclerostin and tartrate-resistant acid phosphatase isoform 5b (TRAP-5b), parathyroid hormone, total alkaline phosphatase (AP), body composition, cardiorespiratory, and functional capacity tests were measured at baseline and after the follow-up. At baseline, carboxylated osteocalcin (GLA) and undercarboxylated osteocalcin (GLU) were inversely correlated with estimated glomerular filtration rate (r=-0.64; r=-0.38, respectively). Both osteocalcin fragments were positively correlated with total AP (GLA: r=0.36; GLU: r=0.53). An inverse correlation was found between GLA and sclerostin with body fat (r=-0.36; r=-0.46, respectively). GLU was negatively correlated with markers of muscle mass (r=-0.34). TRAP-5b and sclerostin were inversely correlated with 6-minute walk test and time up and go test, respectively (r=-0.34; r=-0.35, respectively). After 24weeks, all physical capacity parameters increased in the exercise group (P<.001). Except for total AP that increased after 24weeks in the exercise group (P<.05), no other changes were observed in both groups in relation to the bone metabolism biomarkers investigated. In this post-hoc study, the aerobic training used did not promote relevant changes in the bone metabolism markers investigated.