Best Practice & Research Clinical Endocrinology & Metabolism
1Epidemiology of osteoporosis
Section snippets
Definition of osteoporosis
The definition of osteoporosis has been difficult. A definition based solely on bone mineral density (BMD) does not encompass all the risk factors for fracture, whereas a fracture-based definition will not enable identification of an at-risk population An expert panel convened by the World Health Organization (WHO)5 in 1994 tried to resolve this issue, resulting in the current most widely used definition that encompasses both BMD and previous fracture; osteoporosis is defined as BMD
Prevalence and incidence of osteoporosis
It has been estimated that 10 million Americans >50 years old have osteoporosis, and that a further 34 million are at risk of the disease.4 There are an estimated 1.5 million fragility fractures each year. While most American women under the age of 50 have normal BMD, 27% are osteopenic and 70% are osteoporotic at the hip, lumbar spine or forearm by the age of 80 years.4
Epidemiological studies from North America have estimated the remaining lifetime risk of common fragility fractures to be
Health impact of osteoporotic fracture
All osteoporotic fractures are associated with significant morbidity, but both hip and vertebral fractures are also associated with excess mortality. In the year 2000 there were an estimated 9 million new osteoporotic fractures, of which 1.6 million were at the hip, 1.7 million at the forearm and 1.4 million were clinical vertebral fractures.10
It has been estimated that there are around 740,000 deaths per year associated with hip fracture.11 Osteoporotic fractures account for 0.83% of the
Bone mineral density and fracture
There have been several prospective and cross-sectional epidemiological studies showing that there is an inverse relationship between bone mass and fracture. The risk of osteoporotic fracture increases continuously as BMD declines with a 1.5- to 3-fold increase in risk of fracture for each standard deviation fall in BMD.22 In the Rotterdam Study, a prospective population-based cohort study of 7806 men and women aged 55 years or older, the age-adjusted hazard ratio per standard deviation
Falls and fracture
It is worthy of note that only 1% of falls lead to a hip fracture. This is due mainly to the orientation of the fall, which has been found to be the most important predictor of hip fracture after a fall. Most hip fractures result from individuals falling sideways, failing to break their fall with an outstretched hand, and directly impacting on their greater trochanter.24
Fractures occur due to an interaction between bone fragility, largely determined by bone mass, and trauma (usually due to a
Fracture epidemiology
Fracture incidence in the community is bimodal, with a peak in the young and elderly. In young people, fractures are usually associated with substantial trauma, occur in the long bones, and are seen more frequently in males than females. In this group the question of bone strength rarely arises, although recent data suggest that this may not be entirely irrelevant as a risk factor.29 Osteoporotic fractures characteristically occur in those areas of the skeleton with high amounts of trabecular
Economic cost
In 1997, a conservative estimate of the worldwide direct and indirect annual costs of hip fracture was US $131.5 billion. More recently, the annual cost of all osteoporotic fractures has been estimated at $20 billion in the USA and $30 billion in the European Union. In the UK alone, the annual cost to the health-care system from osteoporotic fracture has been estimated at 1.7 billion pounds. Hip fractures account for over a third of the total figure, and reflect the cost of inpatient medical
Future projections
Osteoporotic fractures represent a significant public health burden which is set to rise in future generations. Life expectancy is increasing around the globe, and the number of elderly individuals is rising within every geographic region. The world population is expected to rise from the current 323 million individuals aged ≥65 years to 1555 million by the year 2050. These demographic changes alone can be expected to increase the number of hip fractures occurring among people aged ≥35 years
Assessment of fracture risk
Currently osteoporosis is defined in terms of BMD. The clinical development of pharmacological agents has focused on the selection of patients on the basis of low BMD for inclusion into trials of efficacy. Thus guidance on whom to treat has emphasized the assessment of BMD. Using T-scores has many benefits, as it is simple and widely used, has a good correlation with fracture risk, and can detect some high-risk patients.5 However, shortcomings include lack of standardization regarding which
Summary
Osteoporosis is a disease that has a huge effect on public health. The impact of osteoporotic fracture is far-reaching not only for the individuals themselves, but for the health service, economy, and population as a whole. Osteoporotic fractures are expected to rise in future generations. Recently several of the risk factors for this disease have been elucidated, and models are currently being developed to allow a more accurate assessment of fracture risk in patients to enable appropriate
References (69)
- et al.
Epidemiology of fractures in England and Wales
Bone
(2001) The clinical impact of vertebral fractures: Quality of life in women with osteoporosis
Bone
(1996)- et al.
Use of selective serotonin-reuptake inhibitors or tricyclic antidepressants and risk of hip fractures in elderly people
Lancet
(1998) - et al.
Epidemiological study of hip fracture in Shenyang Peoples Republic China
Bone
(1999) - et al.
Prevalence of vertebral fractures in French women older than 75 years from the EPIDOS study
Bone
(2004) Diagnosis of osteoporosis and assessment of fracture risk
Lancet
(2002)- et al.
The cost-effectiveness of alendronate in the management of osteoporosis
Bone
(2008) Prophylaxis and treatment of osteoporosis
Osteoporosis International
(1991)A treatise on dislocation and fractures of the joints
(1842)- Technical report series 843. Geneva: WHO 1994. Bartow Dtt (Chairman). Department of Health Advisory group on...