What is osteoporosis?

Osteoporosis (meaning 'porous bones') is a condition that causes bones to become thin, weak and fragile. As a result, even a minor bump or accident can cause a fracture (broken bone). Such events might include falling out of a bed or chair, or tripping and falling while walking. Fractures due to osteoporosis can result in chronic pain, disability, loss of independence and premature death (Bliuc et al. 2013).

This image compares healthy bone with bone affected by osteoporosis. The image shows reduced bone density in the bone affected by osteoporosis compared with healthy bone.

Decreased bone density occurs when bones lose minerals such as calcium faster than the body can replace them (OAMSAC 2014). The decrease in bone mineral density (BMD) and changes in bone quality make bones more fragile and more easily broken than bones of 'normal' density (OAMSAC 2014). Low bone density is known as osteopenia and is the range of bone density between normal bones and osteoporosis.

Risk factors associated with the development of osteoporosis include increasing age, sex, family history of the condition, low vitamin D levels, low intake of calcium, low body weight, smoking, excess alcohol consumption, physical inactivity, long-term corticosteroid use and reduced oestrogen level (Ebeling et al. 2013).

How common is osteoporosis?

Generally, osteoporosis is under-diagnosed. Because osteoporosis has no overt symptoms, it is often not diagnosed until a fracture occurs. It is therefore difficult to determine the true prevalence of the condition (that is, the number of people with the condition). Information about 'diagnosed cases' is likely to underestimate the actual prevalence of the condition.

An estimated 924,000 Australians have osteoporosis, based on self-reported data from the Australian Bureau of Statistics (ABS) 2017–18 National Health Survey (NHS) and 20% of people aged 75 years and over have osteoporosis (ABS 2018). This definition of osteoporosis includes people who had osteoporosis or osteopenia.

Osteoporosis is more common in women than men. In 2017–18, 29% of women aged 75 and over had osteoporosis compared with 10% of men.

Older age groups also tend to be affected. The proportion of women with osteoporosis increases with age, with those 75 and over being most affected (Figure 1).

Figure 1: Prevalence of self-reported osteoporosis by age and sex, 2017–18

The vertical bar chart shows that the prevalence of osteoporosis is most common in people aged 75 and over in both males (10%25) and females (29%25) and least common among people aged 0—44 (0.2%25 in males and 0.3%25 in females).

Note: refers to people who self-reported that they were diagnosed by a doctor or nurse as having osteoporosis or osteopenia (current and long term) and also people who self-reported having osteoporosis or osteopenia.

Source: AIHW analysis of ABS 2019a (Data table).

Aboriginal and Torres Strait Islander people

According to self-reported data from the ABS 2018–19 National Aboriginal and Torres Strait Islander Health Survey (NATSIHS), prevalence of osteoporosis among Aboriginal and Torres Strait Islander people was  2.3%, affecting about 18,900 people —including about 1000 who live in remote areas (0.7% of the remote Indigenous population).

After adjusting for age, twice as many females (5.1%) were affected by the condition than males (2.5%). The prevalence in Indigenous Australians (3.9%) and non-Indigenous Australians (3.3%) was similar overall and for females while the prevalence of osteoporosis was 1.9 times as high in Indigenous males as non-Indigenous males (Figure 2).

Figure 2: Prevalence of osteoporosis by Indigenous status, 2018–19

The vertical bar chart shows that, after adjusting for age, rates of osteoporosis among Indigenous Australians (1.2%25 for males and 4.7%25 for females) were similar to rates for non-indigenous Australians (1.3%25 for males and 4.5%25 for females).

Note: Rates are age-standardised to the Australian population as at 30 June 2001.

Source: ABS 2019b (Data table).