Osteoporosis is caused by bones losing the density of their mineral content. Some people are more at risk than others.
How does osteoporosis develop?
Bones are at their thickest and strongest in early adult life. You gradually start losing bone density after 35. People with osteoporosis lose bone density much faster than normal, meaning they are at risk of fracturing their bones.
Who is at risk of osteoporosis?
Osteoporosis can affect men and women. It is more common in older people, but it can affect younger people too.
Bone health runs in families. If your parent or sibling has ever had osteoporosis or low bone density, you could be at greater risk.
Women are at greater risk of developing osteoporosis than men. This is because changes in hormone levels can affect bone density. The female hormone oestrogen is essential for healthy bones. After the menopause, the level of oestrogen in the body falls, and this can lead to a rapid decrease in bone density. Women are at an even greater risk of developing osteoporosis when:
- they have an early menopause (before the age of 45)
- they have a hysterectomy before the age of 45, particularly when the ovaries are also removed
- their periods are absent for a long time (more than six months) as a result of over-exercising or over-dieting.
For most men who develop osteoporosis, the cause is unknown. However, there is a link to the male hormone testosterone, which helps to keep the bones healthy. Men continue to produce this hormone into old age, but the risk of osteoporosis is increased in men with low levels of testosterone.
Some other causes of osteoporosis include:
- the use of certain medications such as steroids (used for rheumatoid arthritis, asthma and other conditions)
- alcohol misuse
- hypogonadism - a condition that causes abnormally low testosterone levels.
Your risk of osteoporosis can increase if you have certain medical conditions, including:
- hyperthyroidism (overactive thyroid gland)
- disorders of the adrenal glands, such as Cushing's syndrome
- reduced amounts of sex hormones (oestrogen and testosterone)
- disorders of the pituitary gland (a small hormone producing gland under the brain)
- hyperparathyroidism (overactivity of the parathyroid glands)
- conditions that mean you don 't absorb minerals properly, such as coeliac disease and inflammatory bowel disease
- some chronic diseases like rheumatoid arthritis, chronic liver or kidney disease
- if you are taking some medicines, such medicines for breast cancer, prostate cancer, epilepsy and some antidepressants.
Lifestyle factors thought to increase the risk of osteoporosis and broken bones include:
- low levels of physical activity
- excessive alcohol intake
- being either underweight or obese.
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Last reviewed: September 2017