ESTIMATION OF THE EFFECT OF SALMON-CALCITONIN IN ESTABLISHED OSTEOPOROSIS BY BIOCHEMICAL BONE MARKERS

We reviewed data on 42 postmenopausal women with established osteoporo sis (forearm fracture or a low bone mass) who had been randomly treate d for 1 year with either rectal salmon calcitonin (sCT), 100 IU daily (n = 25) or nasal sCT, 200 IU daily (n = 17) applying an estimation al gorithm for bone loss rates. Both groups received a daily calcium supp lement of 500 mg. A group of 18 age-matched women who received no trea tment served as controls. The bone mineral content of the distal forea rm (BMCarm) was measured every 3 months by single photon absorptiometr y. The individual rates of change during the 1-year period were calcul ated by linear regression analysis (alpha BMCarm). Bone loss rates wer e estimated initially and after 1 year of therapy by measurements of s erum alkaline phosphatase, plasma bone Gla protein, and fasting urinar y hydroxyproline and calcium (both corrected for creatinine excretion) according to the estimation algorithm. Both administration forms reve aled significant control group-corrected decreases in serum and urine markers of bone turnover of 15-40% (P < 0.05-0.01) and positive outcom es of 2% in alpha BMCarm (P < 0.01). The estimated effect on bone mass was expressed as the difference between the bone loss estimated after 1 year and initially (triangle ESTBIO). A significant correlation was seen between alpha BMCarm and triangle ESTBIO (r = 0.5, P < 0.0001). We conclude that the effect of sCT on bone can be followed up by bioch emical markers for bone turnover, i.e., by an annual blood and fasting urine sample, applying an estimation algorithm for the rate of bone l oss.