What evidence is there for the prevention and screening of osteoporosis?
Osteoporosis – an excessive decrease in bone mass – is more common in women than in men. It is a particularly common condition among elderly women in affluent countries. Osteoporosis is a risk factor for fractures, which occur most commonly at the wrist, spine and hip. Other important risk factors for fractures include those both related and unrelated to an excessive decrease in bone mass. Those related to an excessive decrease in bone mass include such causes as physical inactivity, smoking, low body weight, a history of fractures and the use of corticosteroids; those unrelated to bone mass loss include such causes as falls, high alcohol intake and visual impairment.
Osteoporosis and the fractures associated with it are a major public health concern, because of related morbidity and disability, diminished quality of life, and mortality. The condition is responsible for about 1700 fractures a day (about 650 000 a year) in the European Union alone. Measures to prevent osteoporosis usually focus on a healthy lifestyle, which includes being physically active, no smoking, and taking adequate amounts of calcium and vitamin D. Pharmaceutical treatment in high-risk groups (such as people with an elevated risk of fracture) and measures to prevent falls are also proposed as important interventions for preventing fractures. Screening for osteoporosis, by measuring bone density or other measures, is suggested to identify and treat people at risk for fracture.
Essentially all studies on osteoporosis focus on women. Virtually no study has addressed it in men.
Some of the most prominent preventable risk factors for fractures are: previous fractures, low bone density, inadequate physical activity, impaired vision, the tendency to fall, smoking, and the use of corticosteroids. Several randomized controlled trials have demonstrated that the physical activity of walking increases the bone density of both the spine and the hip in postmenopausal women. Also, other physical activities, such as aerobics and weight-bearing exercises, increase the bone density of the spine. Moreover, several epidemiological studies have demonstrated that smoking decreases bone density and increases the risk of fractures in both men and women and that quitting smoking decreases the risk of fractures. An increased tendency to fall, due to many factors (such as impaired vision and poor body balance), may be effectively prevented – for example by doing T’ai Chi exercises, doing muscle and balance training, and reducing psychopharmacological treatments.
Strong evidence shows that many different pharmaceuticals are effective in both preventing (by increasing bone density) and treating (by decreasing fractures) osteoporosis in women with an increased risk of fractures after menopause. When taking the most prominent risk factors into account, a modeled cost–effectiveness analysis based on clinical trials suggests that pharmaceuticals can be cost effective also. For women without documented osteoporosis after menopause, there is no evidence that vitamin D alone prevents fractures related to osteoporosis. However, a combination of vitamin D and calcium may reduce the rate of fracture by about 30% – in particular, for people more than 60 years old and for those who show adherence to treatment. Also, the evidence base for the efficacy of preventing fractures in women more than 80 years of age needs to be strengthened.
Although there is no direct evidence that screening for osteoporosis reduces fractures, there is good indirect evidence that screening is effective in identifying postmenopausal women with low bone mineral density and that treating osteoporosis can reduce the risk of fractures (wrist and spine) in this population.
Several measures for preventing osteoporosis show evidence of being effective. Such measures include moderate physical activity, an appropriate intake of calcium and vitamin D, a cessation of smoking, and pharmaceutical intervention in high-risk groups. Also, effective dissemination of findings from research should be used to increase the awareness of osteoporosis, both among the general population and in the health services, to increase early detection of risk factors and to motivate preventive measures.
Although there is some evidence for the indirect effectiveness of selective screening in reducing the risk of fractures (mainly in women over 65 years of age), by identifying and treating those at high risk, there are several questions that remain to be answered before such programmes can be recommended at the population level. Also, the total cost of a general screening programme for women more than 65 years of age may not be affordable or cost effective for many countries. Moreover, there is insufficient evidence of the effectiveness of treating low-risk populations. Furthermore, currently available findings from trials of pharmacological treatments are only relevant under controlled circumstances and to certain risk groups.