The Second Fifty Years Promoting Health and Preventing Disability (1992) / Chapter Skim
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Osteoporosis
Osteoporosis
Pages 76-100
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From page 76... ...
CTinically, osteoporosis is heralded by the occurrence of characteristic fractures or, prior to the onset of fractures, by reduced bone mineral density as assessed by noninvasive techniques. Although some confusion results from the use of these different definitions, the condition is indisputably a common one.
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From page 77... ...
fractures are the most important types. Each year in the United States there may be up to a quarter of a million each of hip fractures and wrist fractures and perhaps twice that number of vertebral fractures.27 More precise figures are difficult to obtain- hip fracture victims are generally hospitalized, but hospital discharge data also count readmissions for additional care.
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From page 78... ...
Still, hip fractures are associated with many deaths and are partly responsible for the fact that falls are the leading cause of accidental death among men and women aged 75 years or older in the United States and the second leacling cause among those aged 45 to 74 years. In contrast, wrist fractures and osteoporotic spine fractures cause no increase in mortality.27 Disability A substantial minority of hip fracture patients are nonambulatory or dependent even before the fracture.
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From page 80... ...
More than 60,000 nursing home a~nissions have been attributed to hip fractures annually,36 along with more than 7 million restricted activity days t62.5 days per episodeJ among noninstitutionaTized indivicluals in the Uniter! States each year.~4 As many as 8 percent of all nursing home residents have hac3 a hip fracture.~4 Functional recovery after a hip fracture is predicted by prefecture independence (in terms of mobility and performing the activities of daily livingJ, mental impairment dementia and psychosis as well as confusion curing hospitalizations, depression, and surgical result, among others.4 3~ 33 There is indirect evidence, however, that these factors can be manipulated to alter recovery outcomes.
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From page 81... ...
Still, vertebral fractures in patients aged 45 years or older account for 52,000 hospital admissions and 161,000 physician office visits each year, as well as more than 5 million restricted activity days. i4 Although it is generally understood that these fractures may lead to progressive loss of height, kyphosis, posture changes, and persistent pain that interferes with activities of daily riving, 46 neither acute nor chronic disabilities associated with vertebral fractures have ever been assessed in a systematic way.
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From page 82... ...
As a consequence, fracture incidence rises dramatically (especially for hip fractures for which the age-related increase is exponential) , and the amount of trauma required to produce a fracture declines.27 Although the occurrence of a fracture is a complex event (Figure 6-21, interventions are usually directed either at bone mass or trauma, and risk factors should be considered in that light.
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From page 83... ...
the two processes are closely coupled so that bone mass remains stable until the early to middle thirties. With aging, however, bone formation does not keep pace with resorption, and bone mass gradually diminishes.
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From page 84... ...
Falling increases the chance of fracture at any given level of bone mass, as does the inability to dissipate the kinetic energy produced by a fall.26 The annual risk of falling rises with age, from about one of five women aged 60 to 64 to one in three aged 80 to 84,6 but only about 5 to 6 percent of falls lead to a fracture of any kind, and only 1 percent lead to a hip fracture. The pathophysiology of falling is not well understood, and many of the risk factors that have been recognized, such as gait and balance disorders, diminished reflexes and strength, or reduced vision,48 are difficult to correct.
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From page 85... ...
However, such generalizations should not obscure the fact that some whites have high bone mass, whereas individual nonwhites may have low bone mass and fractures. Moreover, there seem to be exceptions to the general pattern: Hispanics appear to have hip fracture rates that are even lower than American blacks,45 whereas the Bantu people of South Africa have extremely low fracture rates but also Tow bone mass.27 These observations highlight the need to delineate the factors that determine peak bone mass ant!
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From page 86... ...
One randomized controlled trial showed that only 4 percent of oophorectomized women on ERT lost height compared with 38 percent of women who were not being treated; almost 90 percent of the latter group with height Toss hac3 evidence of vertebral fractures.23 Although randomized trials of ERT for prevention of hip fracture are less feasible owing to the Tong delay between menopause and the typical age at which these fractures occur, case-control studies consistently show about a 50 percent reduction in hip and Colles' fractures with long-term ERT.~7 To intervene by preserving bone density before irreversible bone loss has occurred, patients must be stratified on the basis of fracture risk so that high-risk individuals can be identified. The bone density of any specific individual cannot be determined without direct measurement.~7 A variety of noninvasive bone mass measurement techniques can be used Table 6-2)
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From page 87... ...
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From page 88... ...
These noninvasive tests are safe and well accepted by patients. Moreover, the accuracy of bone mass measurement compares favorably with that of many accepted clinical tests, including such screening tests as those for serum cholesterol.~7 However, the efficacy of osteoporosis screening for preventing fractures has not been demonstrated directly, and no program has been endorsed.40 The level of bone mineral density at which treatment should be initiated for fracture prevention is another criterion that has not yet been determined.~7 At present, this decision is made by individual physicians and patients; the absence of generally accepted guidelines for patient management further hinders the implementation of a population-wide mass screening program for osteoporosis.
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From page 89... ...
The other approved therapy for osteoporosis, caTcitonin, has not been used extensively for preventing bone Toss because of its expense and the need for parenteral administration of present formulations.35 Calcitonin, and investigational drugs like the bisphosphonates, also act by reducing bone Toss. Sodium fluoride, an investigational drug known to increase bone mass in the spine and believed to reduce vertebral fracture rates, has little effect on bone mass in the limbs.
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From page 90... ...
A prospective study that measured rates of bone loss from the vertebrae and radius by serial bone density measurements found no relationship between calcium intake and bone loss.42 In contrast, a cohort study of elderly men and women living in a retirement community in California showed that those who had hip fractures within 14 years after initial evaluation had had a lower calcium intake at the baseline examination. i3 There are no randomized controlled clinical trials that show directly that calcium supplementation prevents fractures.
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From page 91... ...
Finally, it has been suggested that age-related bone loss could result, in part, from a decline in activity and fitness.37 Certainly it is true that bone responds to changes in loading: activity may cause an increase in bone mass, whereas disuse can result in dramatic bone loss.46 One study2i of hospitalized adults who required therapeutic bed rest showed that the bone mineral content in the lumbar spine decreased about 0.9 percent per week (equivalent to one year's worth at normal ratesl, although the rate of loss usually declines over time until a new steady state is reached. The exact pathophysiology of disuse osteoporosis is not known, nor are there specific approaches to remedy the situation except through restored activity.
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From page 92... ...
155-179. of women and 40 percent of men with vertebral or hip fractures.28 The greater proportion of men affected by secondary osteoporosis is due to their Tower background level of the condition men start with greater bone mass, lose bone less rapidly over life, and do not live as long as women.
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From page 93... ...
should be sought for osteoporosis prevention efforts, inclu(ling bone mass screening tests, dmg prophylaxis for bone Toss, and rehabilitation after fracture, once these strategies have demonstrated efficacy in reducing adverse health outcomes.
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From page 94... ...
4. The prevalence and importance of risk factors for osteoporosis should be determined, including estimations of the national population at risk of fracture by virtue of low bone mass (men as well as women and nonwhites as well as whites)
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From page 95... ...
should also be disseminated. APPENDIX SCREENING TESTS FOR OSTEOPOROSIS Many different techniques have been used to assess bone mass.
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From page 96... ...
, which permits direct measurement of bone mineral density (area density in grams per square centimeter) in the proximal femur and lumbar spine.
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From page 97... ...
G., and Wallden, B Prognostic indicators and early home rehabilitation in elderly patients with hip fractures.
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From page 98... ...
Clinical indications for bone mass measurements. Report of the Scientific Advisory Committee of the National Osteoporosis Foundation.
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From page 99... ...
Muscle strength, physical fitness, and weight but not age predict femoral neck bone mass. Journal of Bone and Mineral Research 1989; 4:441448.
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From page 100... ...
D Fracture prediction with bone mass measurements.
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