Osteoporosis in Women with Disabilities
Sarina Schrager, M.D.
Women with physical and cognitive disabilities are at high risk for osteoporosis and osteoporosis-related fractures. Women with physical disabilities frequently are non-ambulatory and have bone loss due to immobility.
Women with cognitive disabilities have high rates of osteopenia and osteoporosis, likely partially due to high rates of anticonvulsant medication use. Women with Down syndrome are at especially high risk of osteopenia and osteoporosis, possibly because of lower peak bone density levels.
Prevention of osteoporosis and related fractures in this population includes population-based measures, such as calcium and vitamin D supplementation and risk-based screening procedures. Primary care providers and specialists need to prioritize osteoporosis prevention strategies when taking care of women with disabilities.
Future research is needed to determine optimal screening and prevention strategies in this very high risk population.
There are over 26 million women with disabilities living in the United States. There are many types of disabilities, ranging from hearing impairment to chronic mental health issues to multiple sclerosis (MS).
The following discussion focuses on women with cognitive disabilities and women with physical disabilities that impair mobility. These two groups of women are at high risk for osteoporosis.
The American Association of Mental Retardation estimates that over 500,000 people with developmental disabilities are over 60 years old. That number is projected to double by 2030.
Prior to the 1970s and 1980s, most women with disabilities were in long-term institutions, and since the move toward deinstitutionalization, many of these women now live in the community. Thus, primary care providers often see women with cognitive disabilities in their practices.
Many studies have shown that women with disabilities receive substandard healthcare. Preventive services, specifically, are underused in this population.
Many women with disabilities have a myriad of health concerns that may reduce their attention to preventive care. Some women with significant cognitive disabilities may be resistant to participating in standard health maintenance activities.
Women with disabilities also face many barriers to receiving primary or preventive care, including access, attitudes of providers and office staff, and lack of information about their healthcare needs.
Osteoporosis is a condition defined as low bone density along with micro-architectural distortion of bone that predisposes to fracture. Bone mineral density (BMD), which is a surrogate measure of bone strength, is an important predictor of fracture.
Hip fractures due to osteoporosis have devastating consequences and carry tremendous mortality and morbidity.
Fractures due to osteoporosis can cause chronic pain and further impair mobility. Increasing age is a major risk factor for osteoporosis, and related fractures can be expected to become more of a problem as the population with disabilities ages.
Bone density measurement may be difficult in women with disabilities. Some women with physical disabilities may not be able to achieve the positioning needed for a central dual photon xray absorptiometry (DEXA) measurement of the hip and spine, the gold standard of BMD measurements.
Some women with cognitive disabilities may not be able to lie still for the time it takes to do a scan. Calcaneal (heel) DEXA and ultrasound are testing options that may be useful alternatives in these situations.
They have shown good correlation with a central DEXA measurement but are not generally used to monitor treatment.[6,7] BMD guidelines were developed using a population of Caucasian women and may not be applicable to a population of women with disabilities.
This paper reviews the available literature on osteoporosis in women with cognitive and physical disabilities.
Papers were obtained through MEDLINE by doing searches combining osteoporosis with disabilities, mental retardation, developmental delay, spinal cord injury, multiple sclerosis, and cognitive delay. Further papers were obtained from the reference sections of each relevant paper read.
Women With Physical Disabilities
Women with physical disabilities that impair mobility have many risk factors for osteoporosis. Such women often are non-ambulatory, frequently taking medications that increase the risk of osteoporosis, and may have lifestyles that do not offer optimal exposure to sunlight, which can predispose to vitamin D deficiency.
Frequent use of steroids for such conditions as MS or myasthenia gravis and anticonvulsant medications for seizure control or behavior management can also predispose to osteoporosis. Low bone density and osteoporosis may be present as early as childhood or adolescence in children with physical disabilities.[9,10]
Immobility has been shown to cause profound bone losses. Loss of mechanical stresses on bones can cause increased osteoclast bone resorption and slowing of osteoblast-driven bone formation. The net result is a decrease in BMD and thinning of cortical bone.
Ultimately, these changes cause an increased risk of fractures. Treatment of disuse or immobilization osteoporosis can include therapeutic exercise, electrical therapy to stimulate muscles, and pharmacological treatments.
Studies of BMD in women after spinal cord injuries have shown rapid bone losses of 25%-50% in the lower extremities in the first few years immediately after injury as a result of sudden immobility.
Subsequently, the rate of loss slows to that of age-matched controls. BMD in the spine and upper extremities in these women may actually increase, however, due to the increasing demands on upper extremity strength.
[13,14] Fractures of the lower extremity are very common after a spinal cord injury and are associated with complication rates of 20%-40%. Surgical repair is very difficult because of the extreme fragility of the bones.
The bones are so porous that surgical pinning is almost impossible. Women who have spastic muscles tend to have less bone loss than women with flaccid muscles, presumably due to the increase in muscle tension on their bones.
MS is a progressive neurological disorder that affects 350,000 people in this country, 75% of whom are women. Women with MS have significantly reduced bone mass, a high prevalence of vitamin D deficiency, and high fracture rates. One study of 54 patients (36 women) with MS found a 22% low-trauma fracture rate compared with 2% in the age-matched and gender-matched control group.
Women with MS have several specific risk factors for low bone density, including poor mobility, frequent use of steroids and other immunosuppressant medications, and vitamin D deficiency. Short courses of steroids may not be related to bone loss in this population, however, as opposed to long-term use.
Women who have inflammatory arthritides, such as rheumatoid arthritis and ankylosing spondylitis, are also at high risk for osteoporosis.[18,19] They have many of the same risk factors for osteoporosis as other women with physical disabilities, including immobilization and frequent use of steroids and immunosuppressant medication.
In addition, women with rheumatoid arthritis have periarticular regional bone loss that is related to disease activity and can lead to localized osteoporosis.
Women With Cognitive Disabilities
Although women with physical disabilities have several clear risk factors for osteoporosis, the reason for the high prevalence of osteoporosis in women with cognitive disabilities is less clear.
The increasing use of anticonvulsant medications for behavior management may contribute to the high osteoporosis rates. One study of 273 adults with developmental disorders found that 40% were taking at least one anticonvulsant medication.
Bone density was correlated with ingestion of anticonvulsant medications, with those people who were taking more than one type of anticonvulsant having the lowest bone density. Anticonvulsant medication, such as phenytoin, carbamazepine, and valproic acid, can alter vitamin D metabolism.[22,23]
Phenytoin and carbamazepine are also direct toxins to osteoblasts. Newer anti-epileptic medications, such as topiramate, gabapentin, lamotrigine, and ethosuximide, may cause lower bone density, although less so than the older medications. In addition, many people with cognitive disabilities also have concomitant seizure disorders and may be at higher risk of traumatic fracture during a seizure.
There have been several studies looking at BMD, the prevalence of osteoporosis, and fracture rates in people with cognitive disabilities (Table 1). Down syndrome (DS) seems to be an independent predictor of low bone mass and risk of fracture.
DS is the most common specified genetic cause of developmental disabilities and is often associated with musculoskeletal disorders. Specifically, many individuals with DS have motor clumsiness that is attributed to hypotonia and joint hypermobility.
Initial bone growth is slow, and the development of bone maturation may be delayed in the first 8 years of life. There is some evidence that children with DS achieve much lower peak bone densities than normal, age-matched controls.
The hypotonia and lower peak bone densities may partially explain the significant increases in low bone density and fracture rates in adulthood among patients with DS.[27,29]
The rate of low bone density and osteoporosis related fractures is higher than in age-matched controls in people with cognitive disabilities who do not have DS as well (Table 1). The largest studies of osteoporosis in people with cognitive disabilities looked at institutionalized patients who may have different risk factors from women living in their own homes or in community-based residential facilities.[30-32] Overall, the rates of osteopenia, osteoporosis, and fractures for women who have cognitive disabilities were significantly higher than in age-matched and gender-matched controls in all studies. The studies of community-based people with developmental disabilities had similar results but much smaller numbers.[34,35] The young women in these studies had lower BMD than age-matched controls, and the studies with older participants found a very high rate of osteoporosis and fracture. Fractures in people with cognitive disabilities present a very difficult management dilemma. Many patients do not have the verbal abilities to inform their caretakers that they have pain and do not understand the rationale for immobilization or medication.
The first step in osteoporosis and fracture prevention is to increase the awareness among primary care providers (PCPs) of the high prevalence of osteoporosis and the high incidence of fractures among the disabled population. In a written questionnaire of 220 women with MS, only 50% were taking calcium supplements and only 29% were taking vitamin D supplements. Furthermore, only 15% of all women and 19% of postmenopausal women surveyed had ever had a BMD test. Both patients and providers need more education about osteoporosis prevention.
PCPs need to be proactive in screening women with disabilities for osteoporosis and need to employ population-based prevention strategies with this group. It is inferred that increased screening will lead to increased treatment and decreases in fractures. Large population studies looking at the outcomes of increased screening and broad prevention strategies need to be performed. PCPs must also attempt to remove all the barriers to obtaining healthcare for women with disabilities to facilitate preventive care as well as disease-oriented care. All women with disabilities should be encouraged to eat a diet high in calcium, and most should take calcium and vitamin D supplements. One exception may be women immediately after a spinal cord injury. The massive bone loss that occurs after an acute spinal cord injury may cause hypercalcemia, and extra calcium supplementation may not be appropriate in that setting. Caretakers and healthcare providers should have a low threshold for obtaining radiographs when a disabled woman has fallen or shows any signs of pain or reluctance to use a body part. For those women who are ambulatory or partially ambulatory, any weight-bearing activity should be encouraged to maintain bone density.
Screening this population for osteoporosis with BMD testing presents several challenges. According to the U.S. Preventive Services Task Force, women with risk factors for osteoporosis should be screened at age 60 as opposed to age 65. These risk factors include smoking, family history of osteoporosis, and previous fracture but do not mention disability. According to several of the studies of women with disabilities reviewed here, the prevalence of osteopenia and osteoporosis is very high in young women as well as in some children. Thus, it may be appropriate to screen exceptionally high risk women at an even earlier age. Consensus guidelines are not currently available.
The question of what type of screening test to use is also a good one. Central DEXA scans are the gold standard but may not be feasible for many women with disabilities because of positioning issues. Calcaneal ultrasound or DEXA may, therefore, be the best choice in this group. According to one expert opinion, the optimal screening method depends on what is available locally and clinically feasible. Calcaneal testing is faster and easier to do and may be the optimal method in this population. Further research must establish the correlation between central and calcaneal measures in women with cognitive and physical disabilities.
No screening program is appropriate if there is not an effective intervention to prevent the ultimate disease. Bisphosphonates are effective for prevention of fractures in women on steroids. There are no prospective trials of bisphosphonates in women on anti-epileptic medications, but the data from steroids can be extrapolated to other medications as well. Bisphosphonates are expensive, however, and necessitate maintaining an upright posture for at least 30 minutes after taking, which may be difficult for some women with disabilities. The risk of esophageal ulceration is likely to be increased in individuals whose disabilities include oral motor dysfunction, a particular concern for women who are nonverbal or whose cognitive impairments preclude self-report of difficulty swallowing the pills. Annual intravenous treatment with zoledronic acid may be a better treatment option in the future for those women who can tolerate intravenous insertion.
Falls are common in the elderly population with disabilities. As people age, their risk of falling increases.
Many people with disabilities take medications that may predispose them to falling, particularly drugs that have anticholinergic side effects, which might be prescribed for incontinence, drooling, neuropathy, allergies, or psychiatric care. Fractures may be more common in ambulatory patients, who have a greater potential for falling.
One study of 268 elderly adults with developmental disabilities determined that falls and injuries were higher in those who were .70 years old, ambulatory, on antipsychotic medication, had suboptimal seizure control, and were exhibiting more destructive behaviors.
Extra precautions should be taken to prevent falls in ambulatory patients and during transfers of non-ambulatory patients. Nonambulatory patients who have regional osteoporosis are still at high risk of fracture during a fall, and special precautions should be taken during transfers or other movements.
Treatment of paraplegic women who may have normal bone density in their upper extremities and osteoporosis in their lower extremities is not clear. Clinical decisions should be made depending on each individual's bone density and risk of falling.
Other standard procedures to minimize the risk of falls in ambulatory patients include corrective eyewear, suitable shoes, maintenance of good lighting, and a safe environment. Screening for risk of falls may be different in the elderly population with disabilities compared with the normal elderly population.
The use of anticonvulsant medications to treat seizures and behavioral disorders is associated with high rates of osteoporosis and fractures. Every effort should be made to keep patients on only one anticonvulsant concurrently because data show that taking more than one anticonvulsant is associated with even lower bone densities.[21,25]
Women on anticonvulsant medications may be candidates for early screening and aggressive prevention strategies. Certainly, all women on anticonvulsant medications should take calcium and vitamin D supplements, even though randomized controlled studies demonstrating the effectiveness of this intervention have not been performed.
In conclusion, osteoporosis is a major problem for all women with physical or cognitive disabilities. PCPs and specialists need to prioritize osteoporosis prevention strategies when taking care of women with disabilities. Future research is needed to determine the best screening and prevention strategies in this very high risk population.
Early screening for osteoporosis is appropriate in this high-risk group of women, and continued vigilance by healthcare providers and primary caretakers is necessary to minimize risks of fracture.
J Womens Health 13(4):431-437, 2004.
Thanks to MEDSCAPE.com
Sarina Schrager, M.D., Department of Family Medicine, University of Wisconsin, 777 S. Mills Street, Madison, WI 53715. E-mail: email@example.com.
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