Bone Abstracts

Background: Osteoporosis is not a homogenous disease. Riggs et al. identified two distinct types of osteoporosis, with different pathophysiology, patterns of bone loss and fracture types.

Post-menopausal (PM) osteoporosis is triggered by withdrawal of the effect of oestrogen on bone, which leads to a sharp acceleration of bone turnover with an imbalance towards excessive osteoclastic activity. Senile osteoporosis in the old old (usually after the age of 75) is a disease of reduced formation. However, data on senile osteoporosis is limited.

Aim and hypothesis: We aim to compare bone turnover markers in a postmenopausal group to the old old. We hypothesise that the difference in their profiles would reflect the differences in underlying mechanisms of osteoporosis.

Methodology: Retrospective audit of all fasting metabolic bone studies (FMBS) performed by the author (CI) in the outpatient clinic during the period 2002–2012. Patients’ were divided into the postmenopausal (age 50–65) (PM) and old-old (age 75 and above) (OO) groups.

Results: Nine hundred and seventy-six FMBS were performed by CI between January 2002 and March 2012. 55 patients met the predefined criteria and were included in the final analysis. P1NP and Albumin were significantly lower in the older group (P<0.05). However, there was no significant difference in bone resorption markers between the two groups.

Discussion: Lower P1NP in the old old group supports the hypothesis by Riggs et al. regarding reduced bone formation in senile osteoporosis A possible reason for the similar resorption is the increase in bone remodelling sites in the old old rather than an increased rate of resorption at each individual site. Furthermore, NTx/Creatinine ratios in urine are influenced by reduced muscle bulk vs renal impairment which has the opposite effects.

Conclusion: This may have implications for treatment in the old old with predominant cortical osteoporosis. Anabolic treatments may be preferable to anti-resorptive therapies. More research is required in this therapeutic area.