title: Biochemical parameters of bone turnover during ten days of bed rest and subsequent mobilization.
abstract: Immobilization is associated with increased bone resorption. To investigate the early onset of increased bone resorption, we evaluated 14 patients who were immobilized for 10 days because of lumbar disc protrusion. The fasting urinary hydroxyproline/creatinine ratio increased significantly after four days (P less than 0.01), reached a peak after 10 days (16.4 +/- 3.3 mumol/mmol, 27.6 +/- 8.8 mumol mmol, P less than 0.01) and returned slowly to baseline values after mobilization. The fasting urinary calcium creatinine ratio followed a similar pattern. Serum calcium and phosphate increased during immobilization (P less than 0.01). Serum 1,25-dihydroxyvitamin D decreased significantly during immobilization (98 +/- 33 pmol/l vs. 79 +/- 36 pmol/l, P less than 0.05), and reached a nadir one week after mobilization (P less than 0.01). We conclude that there is an early significant increment in resorption parameters, with a slow return during the mobilization period. Serum 1,25-dihydroxyvitamin D is suppressed as a result of the increased serum calcium and serum phosphate levels.
authors.affiliation: Department of Endocrinology, Free University Hospital, Amsterdam, The Netherlands.
authors.forename: H E
authors.initials: HE
authors.lastname: van der Wiel
authors.forename: P
authors.initials: P
authors.lastname: Lips
authors.forename: J
authors.initials: J
authors.lastname: Nauta
authors.forename: J C
authors.initials: JC
authors.lastname: Netelenbos
authors.forename: G J
authors.initials: GJ
authors.lastname: Hazenberg
mesh_terms: D000328:Adult; D000469:Alkaline Phosphatase / Q000097:blood; D001510:Bed Rest; D001862:Bone Resorption / Q000378:metabolism*; D001842:Bone and Bones / Q000378:metabolism*; D002112:Calcifediol / Q000097:blood; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000097:blood / Q000652:urine; D003404:Creatinine / Q000652:urine; D005215:Fasting / Q000378:metabolism; D005260:Female; D006801:Humans; D006909:Hydroxyproline / Q000652:urine; D007103:Immobilization / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood
chemical_list: D010281:Parathyroid Hormone; D010710:Phosphates; D015675:Osteocalcin; D003404:Creatinine; D000469:Alkaline Phosphatase; D002117:Calcitriol; D002112:Calcifediol; D006909:Hydroxyproline; D002118:Calcium