Effect of loaded exercise for renal osteodystrophy

We performed bone histomorphometric analysis of biopsy specimens from two patients with hyper- and hypoparathyroidism and a history of long-term hemodialysis (HD) because of diabetes. Case 1, a 53-year-old man with hyperparathyroidism, had been on HD for 22 years, and Case 2, a 54-year-old woman with hypoparathyroidism, for 20 years. Intact parathyroid hormone levels were 1070 and 3 pg/mL, respectively. Case 1 had mixed renal osteodystrophy (fibrous tissue volume to total volume [Fb.V/TV], 5.21%; osteoid volume to bone volume [OV/BV], 19.8%), and Case 2 had adynamic renal osteodystrophy (Fb.V/TV, 0%; OV/BV, 0.54%). Case 1 showed cortical bone thinning (cortical width, 0.2 mm) and porosis (cortical porosity, 14.1%), but case 2 did not (cortical width, 0.84 mm; cortical porosity, 11.6%). Trabecular connectivity of cancellous bone was preserved in both patients, with a bone volume to total volume of 18.2% in case 1 and 35.1% in case 2. Both patients had been doing daily strength training and treadmill walking (2-3 h/day) for over 10 years. Although case I showed cortical thinning and porosis, we suggest that long-term loaded exercise therapy may help to preserve cancellous trabecular bone in both hyperparathyroidism and hypoparathyroidism.