But is it true that we all have to have a bone mineral density (BMD) scan after the age of 50? Here’s who needs to look after their bones

After the age of 50, many people – particularly women who have already gone through the menopause – wonder whether it is time to have a bone mineral density (BMD) scan, the test that measures how ‘dense’ their bones are. The evidence does not suggest that it is necessary for everyone: the benefits observed in studies are small and relate to older women, whilst there is a lack of direct data for men and younger women. To mark World Osteoporosis Day on 20 October 2026, let’s look at when it can really be useful and what we can do to protect our bones at any age.

A bone mineral density (BMD) scan, or bone densitometry, is a test that measures how much mineral, such as calcium, is contained in the bones. The more mineral they contain, the denser and stronger they are. The spine and hip are usually measured during the test. It is a quick and painless test: it takes between 10 and 30 minutes. It uses a very small dose of X-rays, much lower than that of a chest X-ray. The result indicates whether the bones are normal, whether they are slightly lower in mineral content (osteopenia) or whether osteoporosis is likely. However, it does not explain why the bones are in this condition.

Because brittle bones break more easily. We talk about fragility fractures when even a minor fall, such as slipping whilst standing, is enough to break a bone. This happens more often in older people, and particularly in older women, in whom the production of oestrogen – which protects the bones – decreases: in fact, bones are constantly being renewed; part of the bone is broken down and part is rebuilt. When oestrogen levels fall during the menopause, the rate of breakdown increases and the rate of rebuilding cannot keep up, with the result that the bones tend to weaken.

However, the BMD result alone is not enough to predict who will suffer a bone fracture. The risk increases significantly with age, even when bone density remains the same: bone quality deteriorates – a factor distinct from mineral content – and people are more prone to falls. Furthermore, many fragility fractures occur in people whose BMD results are within the normal range or indicate osteopenia – that is, who do not have osteoporosis. For this reason, BMD alone can only partially predict who will suffer a fracture. We have discussed how the risk of fracture increases with age in the fact sheet ‘Do we all have a bit of osteoporosis?’.

That’s right, there is no evidence that it is beneficial for everyone. A systematic review – that is, a study that rigorously compiles and analyses the available research – published in 2025, compared older women invited to undergo screening (a test offered to people without symptoms to identify a risk) with women who were managed as usual by their GP. There were three studies, and the women were on average between 71 and 76 years old.