Objective:  Lumbar spine  (LS) VCF have been reported to be associated with greater loss of health related  quality of life (HRQOL)  than  thoracic spine (TS) VCF (Silverman 2001, Oleksik 2000).Furthermore VCF are associated with greater loss of HRQOL  in older individuals (Silverman 2001, Oleksik 2000). In the old, antiresorptive therapy may be an effective strategy for osteoporosis treatment (Boonen 2004). It is therefore of interest to study the fracture efficacy of CT-NS at the individual vertebral regions, thoracic and lumbar, of the spine in older individuals.

Methods:  A post-hoc analysis of the PROOF study ,1255 postmenopausal OP women, was performed. The 200 IU CT-NS  dosage group was compared to placebo (P) group in terms of both  relative risk reduction (RRR)  and  absolute (ARR) risk reduction for new TS and LS VCF  stratified for age.  

Results: For the all age groups (n = 557), 200 IU NS-CT RRR was 33 %, p< 0.03, and ARR was 8.2%, p=0.02. For TS alone ARR was significant (ARR 6.4%, p=0.04), RRR was 33%, (p=0.06). For LS alone neither RRR or ARR were significant (RRR  33%, p=0.13). For women ³age 70 (n = 238); however, not only was there a significant RRR and ARR for the overall cohort (RRR 44%, p=0.026; ARR 14.3%, p=0.01), but the RRR and ARR were also significant at the LS (RRR 64%, p=0,017; ARR 10.4%, p<0.01. As  well, there was an increasing ARR from years 50-80 in not only the overall cohort and the LS group, but also in the TS group.

Conclusions: These data from the PROOF trial demonstrate  therapeutic benefit of CT-NS  using both RRR and ARR for VCF in postmenopausal OP women of all ages with particular and perhaps preferential benefit for older women greater than age 70 at the lumbar spine and a tolerability profile comparable to placebo. Such findings combined with the known analgesic effect of calcitonin (Pun 1989) are of  clinical importance in considering choice of a therapeutic agent for all women including  older women with osteoporosis.  Furthermore, this is the first study to show with increasing age a preferential benefit at a given spine site of a therapeutic agent used for the treatment of osteoporosis.. Further research is needed with other antiresorptive agents to confirm whether such effects are unique to CT-NS, or are a general effect of all antiresorptive osteoporosis therapies.