In polio survivors there are two types of osteoporosis to be aware of—localized osteoporosis (in the bones of the area that was affected by polio) and generalized osteoporosis potentially affecting many bones of the body. The majority of bone mineralization happens before 30 years of age. Bone formation is stimulated by growth, muscle pull on the bone, and weight-bearing/resistance exercise. In a polio-affected limb there will be less weight-bearing/resistance and less muscle pull so that those bones never become as dense/strong as they would have if that area of the body had not been affected by polio.
Systemic or generalized osteoporosis is very common with advancing age, especially over age 65, in women, in more significantly disabled polio survivors, and in some individuals with lifestyle or medical risk factors for osteoporosis. Long bone fractures, such as in the hip/femur in the leg or the humerus or the radius of the arm, may occur with minimal stress or after a fall. Spinal compression fractures can happen with very minor trauma and can result in long periods of back pain.
Diagnosis of osteoporosis is made either by the presence of a fracture after minimal trauma and/or when the results of a bone density exam (DEXA) show a T-score of -2.5 or greater at one or more of the sites measured. The special x-rays used to measure bone density usually look at the bone in one hip and the lumbar spine. Often the machine is set up to look at the left hip. If a polio survivor’s affected limb is the left leg including the hip, it may be useful to find a facility that can also measure the bone density in a non-affected extremity, such as the right hip or even the forearm. If a post-polio patient has osteoporosis, it is most commonly found in the hip of the most affected leg. Therefore, it is recommended that, if possible, bone density be assessed in the lumbar spine and both hips.
Treatment is primarily directed to preventing falls, increasing weight-bearing exercise if possible, and slowing down or preventing further loss of bone density. This includes recommendations for balance training and fall prevention, use of assistive devices as necessary, dietary recommendations for adequate intake of calcium and Vitamin D, and some medications. It is important to discuss with your physician which of the medications would be recommended for you. When evaluating a particular medication, it is important to know which medications have been shown to decrease fracture risk, not just which improved the T-score. Until recently none of the medications were shown to be able to build new bone, but some of the newer biological agents (generic name ending in “-ab”) have demonstrated some ability to build some new bone, as have two of the drugs with generic names ending in “paratide.” Some of the medications are taken orally and others are taken by injection either under the skin (subcutaneously) or as an intravenous infusion. The prescription of estrogen, a female hormone, has decreased over the last 20 years because of concerns that the risks may be greater than the benefit. Each of the medications has potential side effects, and some of the injectable ones are quite expensive. It is now recommended that the bisphosphonate medications (generic name ending in “-dronate”) not be taken for longer than five years.
Most of the studies on the efficacy of medications for osteoporosis have been completed in women with post-menopausal osteoporosis. The medications mentioned have not been well studied in post-polio individuals. However, in one retrospective chart review, post-polio clinic patients treated with bisphosphonates had an increase in bone mineral density at the hip similar to that seen in a non-polio control group. Post-polio patients treated with bisphosphonates also had a lower fracture risk. However, because of the retrospective nature of this study, definitive recommendations on the use of these medications in the post-polio population cannot be made.
Back support garments and spinal extension exercises if possible may be helpful for easing symptoms of progressive osteoporosis involving the spine. Post-menopausal women should discuss with their physician the pros and cons of bone-density testing, estrogen replacement therapy, or the use of other medications to treat or slow the process of osteoporosis. Both men and women at risk for osteoporosis should maintain a calcium intake of 1,000-1,500 milligrams per day, engage in some type of weight-bearing exercise (see Exercise) at least three times per week if possible, and should have some sun exposure daily or take vitamin D supplements.
References
Alvarez, A., Kremer, R., Weiss, D. R., Benedetti, A., Haziza, M., & Trojan, D. A. (2010). Response of postpoliomyelitis patients to bisphosphonate treatment. PM&R: The Journal of Injury, Function, and Rehabilitation, 2(12), 1094–1103.
Chang, K. H., Tseng, S. H., Lin, Y. C., Lai, C. H., Hsiao, W. T., & Chen, S. C. (2015). The relationship between body composition and femoral neck osteoporosis or osteopenia in adults with previous poliomyelitis. Disability and Health Journal, 8(2), 284–289.
Grill, B., Levangie, P. K., Cole, M., Rosenberg, D., & Jensen, L. (2019). Bone Mineral Density Among Individuals With Residual Lower Limb Weakness After Polio. PM&R: The Journal of Injury, Function, and Rehabilitation, 11(5), 470–475.
Haziza, M., Kremer, R., Benedetti, A., & Trojan, D. A. (2007). Osteoporosis in a postpolio clinic population. Archives of Physical Medicine & Rehabilitation, 88(8), 1030–1035.
Mohammad, A. F., Khan, K. A., Galvin, L., Hardiman, O., & O'Connell, P. G. (2009). High incidence of osteoporosis and fractures in an aging post-polio population. European Neurology, 62(6), 369–374.