Based on the WHO definition of osteoporosis and osteopenia, approximately 3% of men and 13% of women in Australia 50–69 years of age are osteoporotic, rising to 13% and 43% for men and women older than 70 years of age.6 Fifty-five per cent of men and 49% of women between 50 and 69 years of age are osteopenic, with similar prevalences in the over-70 years age group.6 It is estimated that by 2022 approximately 72% of women and 62% of men older than 50 years of age will have osteoporosis or osteopenia, according to WHO criteria.6,7
Approximately 70% of minimal trauma fractures occur in women, with incidence increasing with age in both sexes.6
The residual lifetime risk of minimal trauma fracture is approximately 44% for women older than 60 years of age.8 The residual lifetime fracture risk among men is lower, but still substantial and higher than for many other chronic conditions, being around 25% for those older than 60 years of age.8
Between the ages of 50 and 69, non-hip, non-vertebral fractures (humerus, ankle, lower limb, rib, forearm, pelvis, forearm [not wrist], patella, foot and hand) are the most common minimal trauma fracture types in both men and women.6 Wrist fractures are also common in women in this age group. The hip-fracture rate increases substantially with age, constituting only 4% of fragility fractures in women 50–69 years of age, but 26% of fractures in women older than 70 years of age.6 A similar trend with age is seen in men, although the overall incidence of hip fracture in men remains around one-third of that in women.6 The age-standardised hip-fracture incidence rate declined in Australia between 1997 and 2007, after a rise in the 1980s and stabilisation in the 1990s.9 However, the absolute number of hip fractures increased during this period.9 Any continued decline in incidence will be offset in the coming decades by the effects of an ageing population; the number of Australians older than 70 years of age is set to more than double from 2.2 million to almost five million by 2050.7
Vertebral fractures due to osteoporosis are associated with significant long-term disability due to pain and kyphosis. Vertebral fractures are usually defined on the basis of a 20% or more reduction in vertebral height on X-ray, and are often termed a ‘vertebral deformity’. The prevalence of radiologically identified vertebral deformities ranges from 5% in people aged 50–54 years to 50% in those over 80 years of age.10 In 2012, an estimated 25,502 vertebral fractures occurred in Australia.6 By 2022, incidence is expected to rise to over 35,000, an increase of 37%.6 The underdiagnosis of vertebral fractures is a major problem. Only around one-third of all radiographically observed vertebral deformities come to medical attention (ie are symptomatic with acute fracture-related pain).11 The worldwide Improving Measurements of Persistence on Actonel Treatment (IMPACT) study reported that in Australia, approximately 30% of radiographically visible vertebral fractures in women with osteoporosis are not detected.12
Osteoporosis is a systemic condition. Almost all types of fracture are increased in patients with low BMD, and irrespective of fracture site, adults who sustain a minimal trauma fracture (and possibly even a high trauma fracture) are at subsequently greater (2–4-fold) risk of sustaining another fracture at a different site.6,13 Vertebral deformity is particularly associated with significantly higher risk of subsequent vertebral and non-vertebral fracture.14