Vitamin B(12) and BMD, prostate cancer and osteoporosis and calcitonin therapy
Low plasma vitamin B(12) is associated with lower BMD: The Framingham Osteoporosis Study. See J Bone Miner Res 2005 Jan;20(1):152-9. Epub 2004 Oct 25. Tucker KL and others. PMID: 15619681. This study involved 2576 adults with testing of their plasma vitamin B(12) levels. Results showed, "Both men and women with vitamin B(12) concentrations <148 pM had lower average BMD than those with B(12) above this cut-off. These differences were significant (p<0.05) for men at most hip sites and for women at the spine. Significance remained after further adjustment for protein intake and plasma homocysteine." The authors further concluded, "Vitamin B(12) deficiency may be an important modifiable risk factor for osteoporosis." Editor's comment: Vitamin B12 is found in eggs, meat, poultry, shellfish, and milk and milk products. As can be seen, these are all animal products. So vitamin B(12) deficiency generally occurs more commonly in strict vegetarians. In general vitamin B(12) would not be a prime suspect as a causative agent for osteoporosis, but could be given consideration for anyone who eats strictly vegetarian or who has a very poor diet and not other cause of the osteoporosis has been found.
Physician practices of bone density testing and drug prescribing to prevent or treat osteoporosis during androgen deprivation therapy. See Cancer 2004 Dec 13; [Epub ahead of print], Tanvetyanon T. PMID: 15597384. If PSA levels increase after radical prostatectomy for prostate cancer, androgen deprivation therapy (ADT) is instituted to block the effects of male hormones on the prostate cancer, usually returning PSA levels to normal. One of the side effects of this therapy, however, is decreased bone mineral density (BMD) and/or osteoporosis. Thus it is important for physicians who commence ADT to adequately evaluate and monitor BMD during ADT treatment. This study involved 184 patients receiving ADT for one or more years and evaluated whether they received dual-energy X-ray absorptiometry (DXA), bisphosphonates, calcium or vitamin D supplement, calcitonin, or estrogen during ADT. In summary, no one single type of osteoporosis therapy/preventative intervention was prescribed to even 10% of the patients during the 3-year period of the study. The combined percentage of patients who got even one of the interventions was only 14.7%. The author concluded: "The majority of patients with prostate carcinoma undergoing ADT did not receive interventions to prevent or treat osteoporosis." Editor's comment: Obviously for the patient with prostate cancer undergoing ADT and for his physician, the primary concern is the prostate cancer. But, if osteoporosis is a highly likely side effect of the ADT, then it behooves both the patient and physician to be aware of the complications that result from osteoporosis. Surely a fractured hip or spine would be an unwanted complication, particularly when they are totally avoidable with proper diagnosis and treatment. As a bare minimum, every man undergoing ADT should be on calcium and vitamin D therapy and should be having their BMD monitored either via DXA or biochemical markers of bone breakdown. For results of a study that quantified the amount of bone loss that occurs with ADT over ten years, see the 18th Newsletter
Note: See the 11th newsletter for a cautionary note regarding a possible link between parathyroid hormone (calcitonin) and prostate cancer.
Calcitonin for treating acute pain of osteoporotic vertebral compression fractures: a systematic review of randomized, controlled studies. See Osteoporos Int 2004 Cec 22 [Epub ahead of print], Knopp JA and others. PMID: 15614441. After acute vertebral compression fractures there is often severe pain that requires medications, bed rest and hospitalization. Calcitonin (Miacalcin nasal spray) has the reputation of alleviating the acute pain and reducing the need for other forms of therapy. It has the added benefit of being effective in treating osteoporosis and can either be continued long term or replaced by another osteoporosis medication for the long-term therapy phase of treatment. This study reviewed several controlled clinical trials to see how effective calcitonin therapy is as an analgesic during the acute phase of spinal compression fracture therapy. There were five randomized, controlled clinical trials involving 246 patients which showed calcitonin significantly reduced the severity of pain using a visual analog scale following diagnosis. Pain at rest was reduced as early as one week into treatment and continued weekly for 4 weeks. Side effects were minor and self-limited. The authors concluded, "Calcitonin appears to be effective in the management of acute pain associated with acute osteoporotic vertebral compression fractures by shortening time to mobilization." Editors comment: This analgesic benefit of calcitonin makes it an excellent choice as the agent to start osteoporosis therapy when the patient has a spinal compression fracture. After the initial painful stage of the fracture, then the Miacalcin can be continued long term (see the study below), or one of the bisphosphonates or Forteo could be selected as the long-term medication of choice. Hip fracture reduction has not been shown yet with Miacalcin, so this could be a mitigating circumstance for the long-term osteoporosis therapy of choice. See PMID: 15167766.
The effect of intranasal salmon calcitonin therapy on bone mineral density in idiopathic male osteoporosis without vertebral fractures--An open label study. See Bone 2005 Jan;36(1):47-51. Eput 2004 Nov 25. Toth E and others. PMID: 15664001. This study is interesting on two counts: The beneficial effect of intranasal salmon calcitonin therapy as concerns increased BMD in men with idiopathic osteoporosis and the inability of combined calcium and vitamin D therapy when used as controls to treat idiopathic osteoporosis. For the 71 men in the study who received Miacalcin for 18 months, there was a 3.5% increase in spinal BMD and 3.2% increase in femoral neck BMD. Controls lost approximately 4% of BMD during the study. So, in reality, this was almost an 8% improvement in BMD for the study participants when compared to controls, quite a significant improvement. Note that fracture reduction was not studied, so that very important parameter is still unknown for Miacalcin. Also, note that combined calcium and vitamin D therapy are often suggested both as a way to treat and prevent osteoporosis. Once again, in a controlled clinical study setting, this study shows that calcium and vitamin D are inadequate to treat or prevent osteoporosis. Editor's comment: In the prescribing literature for Miacalcin, it is noted that little or no effect has been found on cortical bone with Miacalcin spray, this includes the hip. So the Toth and others study differs in that respect and I don't know why. But, if low hip BMD is a particular concern, Miacalcin may not be the drug of first choice, so be sure to discuss this with your care provider.