Osteoporosis: Bone Density & DEXA Scan

What osteoporosis is

Osteoporosis is progressive loss of bone density and quality that makes bones fragile. It is called “silent” because it causes no symptoms until a fracture occurs — often from a minor fall or even routine activity after age 50. Hip fractures carry a mortality of around 30% at one year, which is why early detection matters.

Diagnosis is by DEXA bone density scan, not blood tests: a T-score of −2.5 or lower means osteoporosis, between −1.0 and −2.5 is osteopenia, and above −1.0 is normal. In primary osteoporosis the standard blood panel is expected to be normal; blood tests are done to find secondary causes — vitamin D deficiency, coeliac disease, hyperparathyroidism, overactive thyroid, long-term corticosteroids, myeloma — which account for a substantial minority of cases and change management entirely.¹²

Osteoporosis: myths vs facts

Bone health advice is full of half-truths. Here is what the evidence says:

MYTH No symptoms means my bones are fine.

FACT Osteoporosis is silent until a fracture occurs. The first sign is often a fragility fracture from a minor fall — waiting for symptoms means waiting for the fracture.

MYTH Blood tests can diagnose osteoporosis.

FACT Diagnosis is by DEXA scan. Blood tests look for secondary causes that change treatment — a normal blood panel is expected in primary osteoporosis, not a reason to skip the scan.

MYTH Only elderly women get it.

FACT Post-menopausal women are at highest risk, but men are affected too. Long-term corticosteroids are the commonest drug cause, and low BMI, smoking, heavy alcohol, coeliac disease, inflammatory bowel disease and CKD all add risk.

MYTH A reassuring T-score means zero fracture risk.

FACT Density is only one contributor. Age, previous fracture, parental hip fracture, smoking, alcohol, steroid use and rheumatoid arthritis all add risk independently — which is why FRAX combines them with density to estimate ten-year probability.¹

MYTH Once you start treatment, you take it forever.

FACT Treatment is normally reviewed after three to five years rather than continued indefinitely. Dental assessment before starting is advised where extensive work is anticipated.

What to do next

A low bone density result starts a structured workup, not just a prescription:

Read the T-score band, then the FRAX score. T-score −2.5 or below is osteoporosis; but the FRAX 10-year fracture probability — folding in age, previous fractures and steroids — often matters more than the T-score alone for the treatment decision.
Expect blood tests for secondary causes. Calcium, phosphate, alkaline phosphatase, vitamin D, parathyroid hormone, thyroid function, kidney and liver profile, full blood count and coeliac serology. In men and younger people, testosterone is included.
Secure the basics alongside any treatment. Most guidance suggests around 1000–1200 mg/day of calcium (diet plus supplements) and 800–1000 IU/day of vitamin D, since bisphosphonates work poorly without them — and oral bisphosphonates must be taken on an empty stomach with a full glass of plain water, sitting or standing upright for at least half an hour.³
Tackle falls risk as seriously as bone density. Most hip fractures involve a fall: vision, balance, footwear and sedating medication deserve as much attention as the scan result.
Ask about review timing. Treatment is normally reassessed after three to five years — ask your doctor when your next DEXA and review are due.

Practical notes

Bone density changes slowly, so a single DEXA result is less informative than the trend. Scans are usually repeated no more often than every one to two years, because shorter intervals fall within the machine's measurement error. Keep every report in one place — comparing T-scores measured at the same skeletal site (spine or hip) on the same machine is the most reliable way to see change. A brief dated log of any falls or fractures between visits also helps your doctor interpret whether the numbers match your real-world experience.

Several pieces of history help your doctor interpret bone results correctly: a complete medicine list (especially corticosteroids, thyroid hormone, and certain anti-seizure medicines), a family history of hip fracture, smoking and alcohol habits, an estimate of daily dietary calcium, the age of menopause, and the dates of any previous fractures. These same details feed into the FRAX calculator, so bringing them written down saves the appointment for discussion rather than data-gathering.

The lifestyle factors doctors most often discuss for bone health are regular weight-bearing activity such as brisk walking or resistance exercise, getting calcium and vitamin D from food where possible, not smoking, limiting alcohol, and practical falls prevention — good lighting, handrails, sturdy footwear, vision checks, and reviewing medicines that cause dizziness. None of these replaces medical treatment when it is indicated, but they are part of almost every management plan.

Follow-up testing usually follows a rhythm: blood tests for calcium and vitamin D may be checked to correct deficiencies before bone treatment begins, and DEXA is typically repeated every one to two years to judge response. Treatment itself is normally reviewed after three to five years rather than continued indefinitely, so ask your doctor at each visit when your next scan and medication review are due.

In India

A DEXA bone-density scan typically costs ₹1,500–₹3,500 at private diagnostic centres, while the related blood tests — calcium, vitamin D, parathyroid hormone — range from a few hundred rupees to around ₹2,000 each, though prices vary considerably by city and lab.

Look for NABL-accredited laboratories and imaging centres, which follow standardised quality processes. In major cities, most large labs offer home sample collection for the blood tests, though a DEXA scan itself requires a visit to a centre with the machine. Whatever a lab's website says about normal values, the reference range printed on your own report is the one that counts, since ranges differ between machines and assay methods.

Frequently asked questions

What T-score means osteoporosis?

A T-score of −2.5 or lower means osteoporosis; between −1.0 and −2.5 is osteopenia (low bone density); above −1.0 is normal. The score compares your bone density with that of a healthy young adult.

Why do I need blood tests if they cannot diagnose osteoporosis?

To find secondary causes that change management: calcium, phosphate, alkaline phosphatase, vitamin D, parathyroid hormone, thyroid function, kidney and liver profile, full blood count and coeliac serology. In men and younger people the search is more thorough, including testosterone.

What is the FRAX score?

FRAX estimates your 10-year probability of a major osteoporotic fracture from age, BMI, clinical risk factors and optionally the DEXA score. A score above roughly 10–20% indicates treatment benefit — fracture risk and bone density are two different things.

How long is osteoporosis treatment taken?

Treatment is normally reviewed after three to five years rather than continued indefinitely. Bisphosphonates remain first-line for most people; adequate calcium and vitamin D are assumed alongside, since treatment works poorly without them.

What reduces fracture risk besides medication?

Weight-bearing exercise, stopping smoking, limiting alcohol, and falls prevention — most hip fractures involve a fall, so vision, balance, footwear and sedating medication deserve as much attention as the bone itself.

My report says osteopenia, not osteoporosis — do I need treatment?

Not necessarily. Osteopenia means low bone density that has not reached the osteoporosis threshold, and many people with osteopenia never have a fracture. Whether treatment is advised depends on your overall fracture risk — age, previous fractures, steroid use and other factors folded into the FRAX score — rather than the T-score alone, so this is a decision to make with your doctor.

Can I compare T-scores from two different scan centres?

Only cautiously. Different manufacturers' machines and software versions can give slightly different readings, so a small change between centres may reflect the equipment rather than your bones. For monitoring over time, repeating the scan on the same machine is more reliable — mention it to your doctor if you have had to switch centres.

Do I need to fast or prepare before a DEXA scan?

No fasting is needed. Wear clothing without metal zips, buttons or underwires, avoid calcium supplements on the morning of the scan if your centre advises it, and tell the staff if you might be pregnant or have had a recent barium test or contrast scan, since these can affect the reading.

My mother had a hip fracture — should I be screened earlier?

A parental hip fracture is one of the recognised risk factors that raises fracture probability, and it is one of the questions the FRAX calculator asks. Guidelines generally suggest discussing earlier bone-density assessment with your doctor if you have this family history, especially after menopause or if you take long-term steroids.

References

Sources cited on this page. PubMed links open the original abstract.

Kanis JA, Johnell O, De Laet C, et al. A meta-analysis of previous fracture and subsequent fracture risk. Bone. 2004;35(2):375–382. PMID 15268886 · doi:10.1016/j.bone.2004.03.024
Kanis JA, Cooper C, Rizzoli R, Reginster JY. European guidance for the diagnosis and management of osteoporosis in postmenopausal women. Osteoporos Int. 2019;30(1):3–44. PMID 30324412 · doi:10.1007/s00198-018-4704-5
Holick MF. The vitamin D deficiency pandemic: Approaches for diagnosis, treatment and prevention. Rev Endocr Metab Disord. 2017;18(2):153–165. PMID 28516265 · doi:10.1007/s11154-017-9424-1

Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.

Osteoporosis: Bone Loss, DEXA Scores & Prevention