EFFECT OF NASAL SALMON-CALCITONIN ON BONE REMODELING AND BONE MASS INPOSTMENOPAUSAL OSTEOPOROSIS

The effect of nasal salmon calcitonin (SCT) on bone has been investiga ted by densitometry, biochemical markers of bone turnover, and histomo rphometry, 62 women (mean age 65 years) who had experienced Colles' fr acture after menopause were randomized to receive either nasal salmon calcitonin (SCT) 200 IU or nasal placebo daily for 24 months, All rece ived a daily supplement of 0.5 g calcium, There was a significant incr ease above baseline in the bone mineral density of the lumbar spine in the SCT group (2.5%; 95% confidence interval 0.9-4.2%) and in the pla cebo group (1.7%; 95% confidence interval 0.3-3.1%) after 24 months, b ut the difference between the groups was not significant (0.8%; 95% co nfidence interval -1.2-3.0%), Serum levels of osteocalcin decreased si gnificantly below baseline in the SCT group, whereas they were unchang ed in the placebo group, At months 12 and 24, serum levels of osteocal cin were significantly lower in the SCT group than in the placebo grou p (p less than or equal to 0.03), Urinary levels of deoxypyridinoline/ creatinine decreased significantly below baseline in the SCT group, wh ereas only a transient decrease was observed in the placebo group, The differences between the groups were, however, not significant, The er osion depth was significantly lower in the SCT group than in the place bo group after 12 months (median [interquartile range]; 46.9 mu m [10. 4] vs, 50.5 mu m [10.7]; p = 0.03), whereas bone volume and activation frequency did not differ between the groups. This study indicates tha t nasal SCT in a dose of 200 IU daily induces only a minor inhibition of bone resorption and therefore produces only a minor increase in bon e mass. Furthermore, it seems that nasal SCT in a dose of 200 TU does not interfere with the recruitment of new bone multicellular units, bu t preferably decreases ongoing osteoclastic bone resorption.