Low Bone Density & Ankylosing Spondylitis
8/7/06
Why can patients with ankylosing spondylitis (AS) have a more fragile skeleton? According to Dr. Walter P. Maksymowych, one possible reason is that, "We now know that severe inflammation -- wherever it exists -- causes the release of certain chemicals into the blood that activate cells in bone that can literally dissolve bone mineral."
A recent study entitled, "Femoral Bone Mineral Density Is Associated with Vertebral Fractures in Patients with Ankylosing Spondylitis: A Cross-sectional Study", concluded that there is evidence that low bone density as measured in the femur (the thigh bone) of patients was associated with increased risk of vertebrae fracture - or a fracture in the spine - in AS.
How does someone with AS combat the possibility of lowered bone mineral density?
According to Dr. Maksymowych, there is a lot that can be done. "First, patients must make sure that they stay active, not only to preserve strength and flexibility but also to preserve bone mineral. The cells that make bone mineral…love weight-bearing exercise."
Besides exercise, diet can also play an important role. "This means plenty of calcium, about 1500mg per day. A good rule of thumb is that a good helping of a diary product, e.g., yoghurt, cheese, tall glass of skimmed milk, amounts to 300mg of elemental calcium a day." Calcium is an essential nutrient in the formation of bone.
Dr. Maksymowych goes on to state that, "Good nutrition also means 800 units of vitamin D per day." Vitamin D helps the body absorb calcium and is also essential in the maintenance of bones. The body produces vitamin D naturally when exposed to sunshine. However, it is important to note that vitamin D is fat-soluble, thus it is stored in the body. Too much vitamin D can lead to toxic side effects.
One way to see if you may be susceptible to an increased risk of bone or spinal fracture is to undergo a bone density test, which is different than a bone scan. According to the Mayo Clinic's website, MayoClinic.com, a bone density test is, "a test [that] uses special X-rays to measure how many grams of calcium and other bone minerals - collectively known as bone mineral content - are packed into a segment of bone. The higher your mineral content, the denser your bones are. And the denser your bones, the stronger they are and the less likely they are to break."
REFERENCES:
"Expanding The Therapeutic Horizon In Ankylosing Spondylitis", Walter P. Maksymowych, MD; Spondylitis Plus - September/October 2004.
"Femoral Bone Mineral Density Is Associated with Vertebral Fractures in Patients with Ankylosing Spondylitis: A Cross-sectional Study", Jae-Bum Jun, et al. The Journal of Rheumatology; Volume 33: No. 8 August 2006
The Mayo Clinic; MayoClinic.com - http://www.mayoclinic.com/health/bone-density-tests/WO00024