Effect of calcitonin on bone and connective tissue metabolism in hemiplegic patients: a two-year prospective study

To test the effects of 200 IU/day of a nasal spray of salmon calcitonin in modulating the increased bone tissue metabolism observed in hemiplegic patients.

A two-year, prospective, randomized, double-blind, placebo-controlled study.

Thirty-four patients with hemiplegia due to a cerebrovascular accident were included in the study during the first month after onset of hemiplegia after giving their informed consent. All patients followed a suitably planned course of active rehabilitation according to Bobath. They were randomly allocated to either the calcitonin or the placebo group but all of them received a daily oral calcium supplementation of 1000 mg.

Biochemical markers of bone formation, serum total alkaline phosphatase, osteocalcin and type I procollagen did not vary during the two years of follow-up. Cross-linked carboxy-terminal telopeptide of type I collagen, a biochemical marker of bone resorption, was elevated initially after stroke and then decreased significantly (p <0.001), stabilizing as of month 12. Urinary calcium/creatinine and total hydroxyproline/creatinine ratios presented with similar profiles. The serum levels of the type III procollagen, a marker of connective tissue metabolism, were also elevated upon entry and decreased thereafter. No significant difference could be found between the calcitonin-treated and the placebo group for any of the biochemical markers at any time point.

This prospective study demonstrated that biochemical markers of bone and connective tissue metabolism were elevated shortly after the occurrence of stroke and then gradually decreased during the first two years after injury. The daily administration of 200 IU of intranasal calcitonin did not influence the levels of these markers.