THE ASSOCIATION BETWEEN OSTEOPOROSIS AND LIPIDS IN POSTMENOPAUSAL WOMEN: THE EFFECT OF REPLACEMENT THERAPY

Abstract

Background and Objectives: It has been extensively discussed that there is a lowering effect of Replacement Therapy on lipids and lipoproteins. Recent hypotheses relate the lipids and osteoporosis. Thus, there is a possibility that hormone therapy improves osteoporosis not only via direct effect of estrogens on bone tissue, but also via lowering the lipids that may have detrimental effect on bone tissue. The aim of this study was to assess the effect of various regimens of hormone therapy on lipids and osteoporosis and the correlation between lipids and osteoporosis under given hormone treatment.

Methods: Three hundred and thirty five women (n=335) participated in this open study and were assigned to receive orally (a) CEE (n=29), (b) Tibolone (n=75), (c) CEE/MPA (n=57), (d) E2/NETA (n=72), (e) raloxifene (n=64) and (f) no therapy (control) (n=68) for at least 12 months. At baseline and 12 months blood samples were taken and analyzed for lipids and lipoproteins (total cholesterol, triglycerides, HDL, LDL, Lipoprotein (a), Apolipoprotein-A1, Apolipoprotein–B). At baseline and 12 months DEXA was also performed for the measurement of BMD of the lumbar spine.

Results: In the unopposed estrogen group (CEE) most of the variables were negatively connected with osteoporosis and BMD, but none of them were statistically significant. In the raloxifene group similar features were observed, but only LDL reached statistical significance (p=0.0031). In the tibolone group almost all variables were negatively correlated with osteoporosis and BMD, but again only LDL reached statistical significance (p=0.038). In the E2/NETA group most variables were negatively correlated with osteoporosis and BMD, but none reached statistical significance. In the CEE/MPA group all of the variables were negatively correlated with BMD and osteoporosis, but statistical significance was reached by total cholesterol, LDL and Lp(a) (p=0.008, 0.007, 0.047 respectively).

Conclusion: In this study it has been observed that there is a trend in almost every medication group towards an inverse correlation between lipids and BMD. The effect is more prominent in the tibolone, raloxifene and, mainly, in the CEE/MPA group. The greater effect was observed from the point of the lipids, in the LDL variable group. It is very important to clarify whether these findings could be extrapolated at orthopaedic trauma research providing thus a novel explanation for the aetiology of atrophic non unions in patients with compromised vascular function either locally or systematically.