DEXA DESK · SCAN INTERPRETED · TOPIC: OSTEOPOROSIS & BONE DENSITY · REF: NOF / USPSTF / FDA
The Density Report Skeletal health reference · U.S. edition
Metabolic bone disease · Chronic condition

Osteoporosis is silent for decades. Then a fracture makes it loud.

Roughly 10 million American adults have osteoporosis, and another 43 million have low bone mass. Most of them do not know it, because bone loss produces no symptoms — until a wrist, hip, or vertebra breaks. The good news: it is one of the most measurable and most treatable chronic conditions in medicine.

13 min read
NOF-aligned guidance
T-score · 5 drug classes
10M+
U.S. adults have osteoporosis — and 43 million more have low bone mass (osteopenia).
50%
Of women over 50 will have an osteoporosis-related fracture in their lifetime. For men it is 1 in 4.
20%
Mortality in the year following a hip fracture — comparable to some cancers.
-2.5
T-score threshold for diagnosing osteoporosis on DEXA scan.
Section 01 · The T-score

What the DEXA scan actually measures — and what the number means.

A DEXA (dual-energy X-ray absorptiometry) scan measures how much mineral is present in a section of bone. The result is reported as a T-score and a Z-score.

The T-score compares your bone density to that of a healthy 30-year-old adult of the same sex — because peak bone mass occurs around age 30, after which everyone slowly loses bone. The Z-score compares your density to others of your own age and is more relevant in younger patients or when a secondary cause is suspected.

T-scores are expressed as standard deviations from that young-adult peak. A score of 0 is average for a 30-year-old; a score of −1 means slightly below; a score of −2.5 means significantly below. The cutoff for diagnosing osteoporosis is a T-score of −2.5 or lower at the hip, femoral neck, or lumbar spine.

T-score scale · WHO classification
Measured at hip, femoral neck, or lumbar spine
+1.0above avg
−1.0osteopenia begins
−2.5osteoporosis
−3.5severe
≥ −1.0

Normal

Bone density within the expected range for a young adult. Routine rescreening every 2 to 5 years. Focus on calcium, vitamin D, and weight-bearing exercise.

−1.0 to −2.5

Osteopenia (low bone mass)

Below peak but not yet osteoporotic. Whether to treat depends on FRAX fracture risk, prior fractures, and other clinical factors. Many patients in this range are managed with lifestyle alone.

≤ −2.5

Osteoporosis

Bone density low enough that fracture risk is substantially elevated. Pharmacologic treatment is usually recommended, particularly if there has already been a fragility fracture.

One important caveat: a normal T-score does not mean a low fracture risk. The FRAX tool — developed by the World Health Organization — estimates 10-year probability of a major osteoporotic fracture or hip fracture by combining bone density with clinical risk factors such as age, prior fracture, smoking, alcohol use, steroid use, rheumatoid arthritis, and parental hip fracture. Many patients are treated on the basis of FRAX risk even when their T-score is above −2.5.

Section 02 · Bone biology

Bone is not a static scaffold. It is a construction site.

Bone is remodeled continuously throughout life by two cell types working in opposition. Osteoblasts build new bone. Osteoclasts resorb old bone. In healthy adults, the two are balanced — old bone is removed, new bone is laid down, and the structure maintains itself. Peak bone mass is reached around age 30.

After 30, the balance slowly shifts toward resorption. This is normal, and for many people it never leads to disease. But several factors can tip the balance further toward loss: estrogen decline after menopause, long-term glucocorticoid use, low body weight, smoking, excess alcohol, certain medical conditions (hyperthyroidism, hyperparathyroidism, celiac disease, inflammatory bowel disease), and long-term use of proton pump inhibitors or certain seizure medications.

Osteoporosis is not simply "less bone." It is bone with a disrupted architecture — the trabecular struts that give the bone its strength have been thinned and disconnected, and the cortical shell has become porous. That is why osteoporosis fractures occur with falls that would not break a healthy bone: the internal support structure is gone, even if the outer shell looks intact on X-ray.

This also explains why drugs act in two different ways. Antiresorptives — bisphosphonates and denosumab — slow the destruction. Anabolics — teriparatide, abaloparatide, romosozumab — actually stimulate new bone formation. Understanding this distinction is the key to understanding why some patients need one class, some need the other, and some need both in sequence.

Section 03 · Who to screen

When a DEXA scan is recommended.

Who When Notes
Women 65 and older Routine Standard recommendation from USPSTF and most specialty societies. Repeat every 2 to 5 years if the initial scan is normal.
Men 70 and older Routine Osteoporosis in men is under-recognized. Men have higher fracture mortality than women after a hip fracture.
Postmenopausal women under 65 Risk-based Screen if FRAX 10-year risk is elevated or if additional risk factors are present.
Anyone with a fragility fracture Immediately A fracture from a fall at standing height or less is a fragility fracture and warrants evaluation regardless of age.
Long-term glucocorticoid use At initiation Prednisone ≥ 5 mg/day for ≥ 3 months. Steroid-induced bone loss is rapid and treatable.
Patients with secondary causes At diagnosis Hyperparathyroidism, hyperthyroidism, celiac disease, IBD, chronic kidney disease, organ transplant.
Section 04 · Medication classes

Five drug classes — two mechanisms, one goal.

Osteoporosis drugs either slow bone resorption (antiresorptives) or stimulate new bone formation (anabolics). The choice depends on severity, prior fractures, and other conditions.

Bisphosphonates — the first-line standard
Antiresorptive · oral or IV

Bind to bone mineral and are taken up by osteoclasts, which they disable. Reduce fracture risk by 30–50% at the hip and spine in clinical trials. Alendronate and risedronate are weekly oral tablets; zoledronic acid is a once-yearly IV infusion.

Oral bisphosphonates must be taken on an empty stomach with a full glass of water, and you must remain upright for 30 minutes. Esophageal irritation is the main risk of incorrect use. After 3–5 years, many patients take a "drug holiday."

Examplesalendronate · risedronate · ibandronate · zoledronic acid
Denosumab — potent antiresorptive
Monoclonal antibody · every 6 months

A monoclonal antibody that blocks RANKL, the signaling molecule osteoclasts need to mature. Given as a subcutaneous injection every six months. No dose adjustment required for kidney disease — an advantage over bisphosphonates.

Must not be stopped abruptly. Discontinuation causes rapid rebound bone loss and accelerated vertebral fractures — a "bridge" therapy or switch to another drug is required. Also carries rare risk of hypocalcemia and osteonecrosis of the jaw.

Examplesdenosumab (Prolia, Xgeva — higher dose for oncology)
Teriparatide & abaloparatide — anabolic (builds bone)
Daily injection · 18–24 months

Recombinant fragments of parathyroid hormone that stimulate osteoblasts to build new bone. Reserved for severe osteoporosis, multiple fractures, or failure of antiresorptive therapy. Daily subcutaneous injection for up to 18–24 months.

Must be followed by an antiresorptive — otherwise the newly built bone is rapidly lost. Because of a theoretical osteosarcoma risk observed in rats, they are avoided in patients with prior bone cancer or unexplained elevated alkaline phosphatase.

Examplesteriparatide (Forteo) · abaloparatide (Tymlos)
Romosozumab — dual-action anabolic
Monthly injection · 12 months

Blocks sclerostin, which simultaneously increases bone formation and reduces bone resorption — a mechanism unique among osteoporosis drugs. Monthly subcutaneous injection for 12 months, followed by an antiresorptive.

FDA boxed warning for cardiovascular events based on trial signal in patients with recent heart attack or stroke. Not appropriate for patients with significant cardiovascular history in the past year.

Examplesromosozumab (Evenity)
SERMs & estrogen — selective context
Raloxifene · HRT

Raloxifene is a selective estrogen receptor modulator that reduces vertebral fracture risk but not hip fracture risk. Also reduces risk of invasive breast cancer — a secondary benefit that occasionally drives the choice.

Systemic hormone therapy (estrogen ± progestin) prevents bone loss and is approved for osteoporosis prevention, but its role has narrowed since the Women's Health Initiative. Still appropriate for some women with menopausal symptoms and elevated fracture risk.

Examplesraloxifene (Evista) · conjugated estrogens · estradiol

A note on osteonecrosis of the jaw (ONJ). This rare complication is associated with antiresorptive medications, particularly high-dose IV formulations used in cancer patients, but it also occurs in the much larger osteoporosis population at very low rates. Good dental hygiene and completing any major dental work before starting therapy are the main preventive measures. Routine dental cleanings can continue during treatment.

Section 05 · Calcium & vitamin D

Two nutrients the skeleton needs — and how much.

1,200 mg/day

Calcium — total daily intake

For women over 50 and men over 70. Food first, supplements only to fill the gap. A typical U.S. diet provides 600–800 mg; most patients need 300–600 mg from supplements at most. Take in divided doses of ≤ 500 mg for best absorption.

800–1,000 IU/day

Vitamin D — daily maintenance

For adults over 50. Some patients need higher doses based on serum 25-hydroxyvitamin D level. Take with a fat-containing meal — vitamin D is fat-soluble and absorbs better with food.

20 g/day

Protein — often overlooked

Older adults frequently under-consume protein, which impairs bone and muscle maintenance. 1.0 to 1.2 g/kg body weight per day is a reasonable target and matters as much as calcium for fall prevention.

Avoid excess

What not to overdo

Very high-dose calcium supplements have been linked to kidney stones. Excess vitamin A and high-dose retinol may increase fracture risk. Routine high-dose vitamin D (over 4,000 IU) is not beneficial and may be harmful.

Section 06 · Fall prevention

Most fractures are caused by a fall. Most falls are preventable.

Preventing falls is at least as important as improving bone density — a stronger bone that is not fallen on does not break.

Strength & balance training

Resistance exercise and progressive balance training — including tai chi — reduce falls by 20–30% in older adults. Weight-bearing activity also stimulates bone formation.

Medication review

Sedatives, sleep aids, antihypertensives, and antidepressants increase fall risk. An annual review with a pharmacist frequently identifies a safer alternative or a lower dose.

Home hazard modification

Grab bars in bathrooms, handrails on both sides of stairs, adequate lighting, non-slip mats, removal of loose rugs. An occupational therapy home evaluation often catches hazards patients miss.

Vision & footwear

Annual eye exams; cataract surgery when indicated reduces falls. Supportive, low-heeled shoes — not slippers or bare feet — improve stability. Avoid multifocal lenses on stairs.

Vitamin D for muscle function

Beyond bone, vitamin D influences muscle strength and postural stability. Correcting deficiency reduces fall risk in older adults, even independently of bone density.

Section 07 · What to watch for

When bone loss needs more than routine management.

Evaluate further

If any of these apply, tell a clinician before starting or continuing osteoporosis treatment.

New back pain after minimal trauma or a loss of height greater than 4 cm. May indicate a vertebral compression fracture — one of the most common and most often missed osteoporotic fractures.
Osteoporosis in a premenopausal woman or man under 50. Secondary causes must be ruled out: hyperparathyroidism, celiac disease, hypogonadism, malabsorption, or medication effects.
Failure of bisphosphonate therapy — continued bone loss or a new fracture despite adherence. Consider switching to an anabolic agent, or evaluating for an unrecognized secondary cause.
New thigh or groin pain on long-term bisphosphonates. Rare but important sign of an atypical femur fracture. Requires prompt imaging — do not attribute to muscle strain.
Jaw pain, exposed bone, or non-healing dental extraction site. Possible osteonecrosis of the jaw. Requires dental and specialist evaluation; antiresorptive therapy may need to be paused.
Recent heart attack or stroke before starting romosozumab. The FDA boxed warning applies within the past 12 months. Consider an alternative.
Section 08 · Access & affordability

Osteoporosis medication is available as generics. The price still varies.

Several osteoporosis medications are available as low-cost generics in the United States. Alendronate, risedronate, ibandronate, and raloxifene are all generic and priced well below their original brand versions. Zoledronic acid is available as a generic infusion. Calcium and vitamin D supplements are over the counter at low cost. Denosumab (Prolia) is now available as a biosimilar, which has substantially lowered the cost of that option. Anabolic agents — teriparatide, abaloparatide, romosozumab — remain brand-only and expensive.

What matters in practice: the same generic tablet can cost several times more at one licensed pharmacy than another. A weekly alendronate tablet that costs $12 at one pharmacy may cost $40 at another. A live prescription price comparison shows the current range in about two minutes, and the same logic applies to every generic on a patient's list. For a first-time online refill, the process is documented step by step in this how to order prescriptions online guide — prescription first, licensed seller second, small first order third.

One warning specific to osteoporosis medication: do not stop taking a bisphosphonate or denosumab because the scan improved. Bone density gains reverse quickly after discontinuation — and in the case of denosumab, may actually be accompanied by a rebound increase in fracture risk. Any decision to pause or stop should be made with the prescriber, and often involves a "bridge" plan.

Before filling from any seller — online or local — verify them. A working VIPPS seal that resolves to a live NABP record, a real U.S. street address, and a prescription requirement that cannot be waived. A transparency page like this one about Metformin4You is a reasonable example of the standard to expect.

Section 09 · Questions

Five asked most often at the bone clinic.

Q·01 What does a T-score of -2.5 mean? +
A T-score of -2.5 or below is the diagnostic threshold for osteoporosis. T-scores compare your bone density to that of a healthy 30-year-old adult of the same sex. A score between -1.0 and -2.5 is called osteopenia (low bone mass), and a score above -1.0 is considered normal.
Q·02 How often should I get a DEXA scan? +
Guidelines recommend DEXA screening for all women 65 and older and for men 70 and older, and earlier for anyone with risk factors. If the initial scan is normal, repeat every 2 to 5 years. If it shows osteopenia or osteoporosis, or if treatment is started, repeat every 1 to 2 years to monitor response.
Q·03 Are bisphosphonates safe for long-term use? +
Bisphosphonates are generally safe and well studied, but after 3 to 5 years of treatment, many guidelines recommend a drug holiday for patients whose fracture risk has decreased. Prolonged continuous use has been linked to rare atypical femur fractures and osteonecrosis of the jaw. The decision to continue, pause, or switch should be made with a clinician based on individual risk.
Q·04 How much calcium and vitamin D do I actually need? +
For adults over 50, the recommended total calcium intake is 1,200 mg per day, ideally from food first and supplements only to fill the gap. Vitamin D is typically 800 to 1,000 IU daily for adults over 50, though some patients need more based on blood levels. Very high-dose calcium supplements have been associated with kidney stones and possibly cardiovascular concerns.
Q·05 Can osteoporosis be reversed? +
Osteoporosis cannot usually be fully reversed, but bone density can be meaningfully increased and fracture risk substantially reduced with treatment. Anabolic medications such as teriparatide and romosozumab can build new bone, while antiresorptives such as bisphosphonates slow bone loss. The goal is fewer fractures, which is what actually matters.
◆ Sources & Verification
This reference is aligned with public clinical guidance from the Bone Health & Osteoporosis Foundation, the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIH), the U.S. Preventive Services Task Force osteoporosis screening recommendations, and the U.S. Food and Drug Administration's BeSafeRx program. Drug-label information draws on the National Library of Medicine's DailyMed database and MedlinePlus. Pharmacy verification follows the NABP VIPPS program.
◆ Before the next refill

Bone health is a long game. So is prescription pricing.

Most osteoporosis medications are available as low-cost generics, and the same tablet can cost several times more at one licensed pharmacy than another. A two-minute comparison across licensed U.S. sellers is a useful habit to build. Begin with the current Metformin price comparison as a live demonstration of how wide the spread runs.

Open the price comparison