FEWER BONE HISTOMORPHOMETRIC ABNORMALITIES WITH INTERMITTENT THAN WITH CONTINUOUS SLOW-RELEASE SODIUM-FLUORIDE THERAPY

Citation
Cm. Schnitzler et al., FEWER BONE HISTOMORPHOMETRIC ABNORMALITIES WITH INTERMITTENT THAN WITH CONTINUOUS SLOW-RELEASE SODIUM-FLUORIDE THERAPY, Osteoporosis international, 7(4), 1997, pp. 376-389
Citations number
39
Categorie Soggetti
Orthopedics,"Endocrynology & Metabolism
Journal title
ISSN journal
0937941X
Volume
7
Issue
4
Year of publication
1997
Pages
376 - 389
Database
ISI
SICI code
0937-941X(1997)7:4<376:FBHAWI>2.0.ZU;2-N
Abstract
To help resolve the uncertainty whether sodium fluoride (NaF) therapy should be given intermittently or continuously, we examined iliac cres t bone biopsies (before and after treatment) and fragility fracture ra tes in 35 intermittently treated (group I) and 69 continuously treated (group C) patients; all received calcium. The following statistically significant results were obtained, Reduction in vertebral fracture ra te was similar in the two groups. Trabecular thickness and the structu rally more important mineralized thickness increased only in group I. Group I also accumulated less excess osteoid (surface, volume). Mean o steoid thickness did not change in either group because of a bimodal d istribution of wide seams with osteoblasts and double tetracycline lab els, and thin seams without osteoblasts or labels. Osteoid was lamella r. Osteoid in abnormal sites (within bone marrow or bone, or around os teocytes) was found less frequently in group I. Adjusted apposition ra te declined and mineralization lag time increased in both groups becau se of extended unlabelled osteoid seams. Erosion surface increased onl y in group C. Hook and/or tunnel erosion was seen less frequently in g roup I; it was closely associated with osteoid in abnormal sites and c orrelated with osteoid surface. Extended osteoid surface may have forc ed osteoclasts to hollow out trabeculae, leaving the empty osteoid she ll in marrow. Excess osteoid volume and eroded surface and osteoid and erosion in abnormal sites correlated with bone fragility in group C. We conclude that intermittent therapy is to be preferred because it (1 ) increased mineralized trabecular thickness, (2) did not cause excess ive osteoid accumulation and erosion, (3) showed less osteoid and eros ion in abnormal sites and (4) led to a similar reduction in the verteb ral fracture rate as did continuous treatment. The question of whether intermittency of therapy has some other effect independent of the cum ulative dose of fluoride administered cannot be answered by this study .