Men's Osteoporosis Support GroupControlled release of salmon calcitonin; trabecular bone score; walking increases BMD; not taking bisphosphonates increases fracture risk; and biomechanically-based methods of fracture risk prediction Pharm Res. 2009 Dec 9. [Epub ahead of print]. Thermosensitive Drug Delivery System of Salmon Calcitonin: In Vitro Release, In Vivo Absorption, Bioactivity and Therapeutic Efficacies. Tang Y, Singh J. PMID: 19998055. This study on rats appears to be the first one showing an injectable, long-acting, controlled release system may work with salmon calcitonin to treat or prevent osteoporosis. Currently the only formulations that are FDA approved that I'm aware of are a daily injection and a daily nasal spray, Miacalcin. I believe that a daily pill is also in clinical trials. So this is just a heads up that another osteoporosis medication may be coming if further tests and clinical trials verify the results shown here. Here is an Update regarding salmon calcitonin. Calcif Tissue Int. 2009 Dec 9. [Epub ahead of print]. A Retrospective Case-Control Study Assessing the Role of Trabecular Bone Score in Postmenopausal Caucasian Women with Osteopenia: Analyzing the Odds of Vertebral Fracture. Winzenrieth R and others. PMID: 19998029. Currently osteoporosis is defined based upon bone mineral density (BMD), with -2.5 S.D. or less the cut-off point for osteoporosis. This doesn't take into account any other factors related to fracture risk: bone quality or strength, body morphology, risk of falling, etc. This study tested to see if trabecular bone score (TBS), data which can be calculated from a standard dual-energy X-ray absorptiometry (DXA) done when testing for osteoporosis, could be an accurate predictor of fracture risk. The authors compared 81 women with osteoporosis-related vertebral fractures with 162 age-matched controls without fractures. They actually found that the trabecular bone score was a more accurate predictor of fracture than BMD. And combining BMD and TBS was slightly better than TBS alone. The authors stated, "In conclusion, the TBS warrants a closer look to see whether it may be of clinical usefulness in the determination of fracture risk in postmenopausal osteopenic women." Editor's comments. I suspect we'll be hearing more about TBS in the future. Since it requires no extra testing, apparently just additional analysis of the data that is already there when you have a DXA, this is promising. It appears to be almost twice as accurate a predictor of fracture risk, at least in this one study. You can read the Related Articles and see that other studies haven't found the same results. For more information on the Area Under the Curve aspect of statistics cited in this study, this site has a nice description which will explain how to interpret the numbers. The OR (odds ratio) statistic could be confused with the RR (relative risk) statistic. Here is a nice explanation of the two comparing survivors on the Titanic. Osteoporos Int. 2009 Dec 9. [Epub ahead of print]. Pedometer determined ambulatory activity and bone mass: a population-based longitudinal study in older adults. Foley S, Quinn S, Jones G. PMID: 19997903. Here is the authors' summation of this study, "In this large population-based study, walking was assessed twice yearly for a week, each time by pedometer, had consistent clinically important associations with hip areal bone mineral density (aBMD) in both sexes which appears most important in those over 65 years of age suggesting that walking becomes more important with increasing age." I'll let you read the details if you want more specifics on how it was conducted. Essentially they found that those who walked the most had the greatest hip BMD, especially if older than age 65. That was not the case for the spine. Editor's comments. These results are logical when you consider what body parts are stressed during walking. The weight and stress are transferred from the feet, through the ankle, then the lower and upper leg bones, eventually to the hip joint itself. Thus we would expect the hips to demonstrate increased BMD, if any bones or joints would, since they get the greatest stress during weight-bearing lower body exercise. The fact that the spine BMD didn't correlate with walking is also logical. I would expect something like overhead weight lifting to maximally stress the spine would be needed to increase spine BMD while walking. Thus if a sub-group in this study had lifted weights over their head while walking, I would think their spines would have also shown a direct correlation to the recorded pedometer distance. Or similarly, perhaps just carrying extra weight anywhere from the shoulders up would increase spinal BMD. Since this adds weight throughout the entire body, it should also improve the increase in hip BMD as it improves spine BMD. The other thing I wonder that might contribute to improving BMD in this study, but that apparently wasn't measured, is vitamin D status. I would think that those doing the most steps are likely to be doing at least a significant amount of their walking outdoors in sunlight. That would increase their serum vitamin D level, and possibly also improve BMD. Osteoporos Int. 2009 Dec 5. [Epub ahead of print]. Poor bisphosphonate adherence for treatment of osteoporosis increases fracture risk: systematic review and meta-analysis. Imaz I and others. PMID: 19967338. This is a meta-analysis of several articles covering hundreds of thousands of patients who were followed for at least one year to see if they were taking their bisphosphonate osteoporosis medications. That is, if they were adherent to treatment. They found that there was ". . . 46% increased fracture risk in non-compliant patients versus compliant patients. The increased fracture risk was lower for non-vertebral (16%) and hip (28%) than for clinical vertebral fractures (43%)." The authors concluded, "Persistence and compliance are suboptimal for postmenopausal women undergoing bisphosphonate therapy for osteoporosis. The clinical consequence of this low compliance is an increased risk of fracture, which is lower for non-vertebral than for clinical vertebral fractures." Editor's comments. There are several articles on this site regarding the poor adherence and compliance that people have regarding taking osteoporosis medications. This Update covers three articles and explains that at least 80% compliance seems to be required to get adequate fracture prevention. Thus if you are taking a bisphosphonate for only 75% of the time, it is a waste of time and money. And, as the Imaz and others study shows, you are at much greater risk of a fracture while still paying for, or costing someone, the price of the medication. It's interesting that here in the United States the Congress is currently debating major changes to healthcare legislation. The people who are prescribed these medications don't pay for them directly, they are likely paid by an insurance company, Medicare, etc. And some of them are quite expensive. Yet there is no requirement that the individual actually take the medications. That then results in a very large additional expense, beyond the cost of the medications, to treat the fractures that occur. This also not being paid directly by the patient but by some other party--and often eventually the taxpayers. One would hope the new legislation has some way of reducing or removing all these added expenses caused by non-compliance on the part of those with osteoporosis. Bone. 2009 Oct 22. [Epub ahead of print]. Comparison of hip fracture risk prediction by femoral BMD and by the factor of risk for hip fracture derived from direct measurements of femoral strength. Roberts BJ and others. PMID: 19854307. Using 73 human cadaveric femurs the authors compared the fracture risk when using aBMD or when using the ratio of applied load to bone strength, termed the factor of risk (Phi). They mechanically tested the femurs to failure in a sideways fall configuration. If the Phi is greater than one that is considered a high risk for fracture in a sidewise fall. 98% of the femurs with a BMD of -2.5 S.D. or less had a Phi >1. However, 10/19 (53%) of specimens with FN (femoral neck) aBMD T-score above -2.5 also had Phi>1. The authors noted, ". . . about 50% of individuals not designated as osteoporotic by aBMD testing would be at high risk for hip fracture should they experience a sideways fall. These findings strongly support the investigation of new biomechanically-based methods of fracture risk prediction." Editor's comments. The ideal would be to have a highly predictive way to determine fracture risk. BMD is part of the answer, but not all of it. This method that uses biomechanically-based methods might be a helpful addition. I'll look forward to posting future studies if they confirm the work of this one. Older individuals, with decreased BMD and higher fracture risk, would be wise to consider taking an approved osteoporosis medication they can comply with 100% of the time, and they should do all they can to reduce the risk of falls.
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