Osteoporosis and osteopenia
Based on the WHO definition of osteoporosis and osteopenia, approximately 3% of men and 13% of women in Australia aged 50–69 years are osteoporotic, rising to 13% and 43% for men and women aged >70 years.12 Fifty-five per cent of men and 49% of women between 50 and 69 years of age are osteopenic, with a similar prevalence in those aged >70 years.12 By 2022, approximately 72% of women and 62% of men aged >50 years will have osteoporosis or osteopenia based on WHO criteria.12,13
Minimal trauma fractures
Approximately 70% of minimal trauma fractures occur in women, with incidence increasing with age in both sexes.12 The residual lifetime risk of minimal trauma fracture is approximately 44% for women aged >60 years, which is higher than the risk of ischaemic heart disease or some types of cancers (e.g., breast cancer).14 In men of the same age group, the lifetime fracture risk is lower (at 25%) and comparable to the lifetime risk of developing diabetes.14
Between the ages of 50 and 69 years, non-hip, non-vertebral fractures (humerus, ankle, lower limb, rib, forearm, proximal pelvis, patella, foot, and hand) are the most common minimal trauma fracture types in both men and women.12,13 Wrist fractures are also common in women in this age group.
Hip fractures
The hip fracture rate increases substantially with age, constituting only 4% of fragility fractures in women aged 50–69 years, but 26% of fractures in women aged >70 years.12 A similar trend with age is seen in men, although the overall incidence of hip fracture in men remains around one-third that in women.12 After a rise in the 1980s and stabilisation in the 1990s, the age-standardised hip fracture incidence rate declined in Australia between 1997 and 2007.15 However, the absolute number of hip fractures increased during this period due to population ageing.15 Any continued decline in incidence rate will be offset by the ageing population – the number of Australians aged >65 years is set to more than double from 4.2 million in 2020 to almost 10.2 million by 2066.14
Vertebral fractures
Vertebral fractures due to osteoporosis are associated with significant long-term disability due to pain and kyphosis. Vertebral fractures are usually defined as a 20% or greater 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 aged >80 years.16 In 2012, an estimated 25,502 vertebral fractures occurred in Australia12 and by 2022 this incidence was expected to rise to over 35,000, an increase of 37%.12 Underdiagnosis of vertebral fractures is a major problem, because incident radiographic vertebral fractures are associated with a significantly higher risk of subsequent vertebral and non-vertebral fracture.12 Only around one-third of all radiographically observed vertebral deformities come to medical attention (i.e., are symptomatic with acute fracture-related pain).17 In Australia, approximately 30% of radiographically visible vertebral fractures in women with osteoporosis are not detected.18
Osteoporosis is a systemic condition. Almost all fracture types are increased in patients with low BMD. All fracture sites apart from rib fractures (in men) increase subsequent fracture risk by two- to fourfold.12,19 Moderate to high trauma fractures are also associated with increased fracture risk.20