Bone Density Scan in Thyroid Care
Thyroid hormone affects bone turnover. Long-standing untreated hyperthyroidism and prolonged over-replacement with levothyroxine can reduce bone density, increasing fracture risk — particularly in postmenopausal women and older adults.
A bone density scan (DXA) measures bone mineral density and helps decide whether treatment is needed.
Last medically reviewed: 15 November 2025
Key points
- Overactive thyroid and over-replacement can thin the bones.
- DXA is a quick, low-radiation scan of the hip and spine.
- It is considered in prolonged hyperthyroidism or TSH suppression.
- Bone health also depends on calcium, vitamin D, activity and other risk factors.
Why thyroid disease affects bone
Thyroid hormone accelerates bone remodelling, favouring breakdown over formation when levels are persistently high. This can reduce bone mineral density over time.
The effect is most relevant in postmenopausal women, older adults and people on long-term TSH suppression after thyroid cancer.
Who should be scanned
A DXA scan may be considered in people with prolonged hyperthyroidism, those on long-term suppressive levothyroxine, and those with additional fracture risk factors such as age, menopause, smoking or steroid use.
The decision is individualised with your clinician.
What the scan involves
DXA is painless and uses a very small radiation dose. You lie on a table while the scanner measures bone density at the hip and spine. The result is a T-score comparing you with a young healthy adult.
The scan takes only a few minutes and requires no special preparation.
What happens next
If bone density is low, management may include calcium and vitamin D, weight-bearing exercise, review of thyroid dosing, and sometimes bone-protective medication.
Repeat scans are arranged at intervals depending on the result and treatment.
When to seek urgent medical help
- Sudden severe back pain or loss of height.
- A fracture from a minor fall.
- New symptoms of over-replacement such as palpitations or weight loss on levothyroxine.
This guidance does not replace emergency services. If you are seriously unwell, seek urgent medical care immediately.
Frequently asked questions
Does thyroid disease affect bone density?
Yes — long-standing overactive thyroid and prolonged over-replacement with thyroid hormone can reduce bone density.
Is DXA safe?
Yes — it uses a very small radiation dose and is painless.
Will treating my thyroid protect my bones?
Correcting thyroid function removes the excess hormone effect, but other measures such as calcium, vitamin D and exercise also matter.
How often should I have a scan?
The interval depends on your results and risk factors — often every few years if stable.
References & further reading
This page is based on established medical knowledge and guidelines from authoritative sources. Always consult a qualified clinician for personal medical advice.
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