Bone loss is a quiet process. It rarely announces itself before a fracture, and by then the disease has often been present for years. Osteoporosis is common, treatable, and dramatically under-diagnosed, particularly in women in the decade after menopause and in men over seventy.
The screening test is straightforward: a DEXA scan, which uses low-dose x-ray to measure bone mineral density at the hip and spine. It takes about fifteen minutes, involves no injections, and delivers a number that maps directly to fracture risk.
When screening is recommended
The U.S. Preventive Services Task Force recommends DEXA screening for women aged 65 and older, and for younger postmenopausal women whose fracture risk is equivalent to that of a 65-year-old white woman. Risk can be estimated with the FRAX tool, which uses age, weight, prior fracture, parental hip fracture, smoking, alcohol, and steroid use to generate a ten-year probability.
Guidance for men is less firm. Many endocrinology groups suggest screening men at 70, or earlier for those with a history of fragility fracture, low body weight, long-term glucocorticoid use, androgen deprivation therapy, or a condition such as celiac disease or hyperparathyroidism that accelerates bone loss.
Once a baseline is established, repeat testing is typically every two years, though a normal result in a low-risk woman can reasonably be followed less often.
Reading the result
A DEXA report gives two numbers. The T-score compares your density to that of a healthy young adult and defines the diagnosis: -1.0 or higher is normal, between -1.0 and -2.5 is osteopenia, and -2.5 or lower is osteoporosis. The Z-score compares you to age-matched peers and flags cases where secondary causes deserve investigation.
A diagnosis of osteopenia is not, on its own, a reason for medication. The right question is not the T-score alone but the ten-year fracture risk generated by FRAX using the DEXA result. When that risk crosses roughly three percent for hip fracture or twenty percent for any major osteoporotic fracture, treatment is generally recommended.
What actually reduces fracture risk
Prevention is unglamorous but effective.
- Weight-bearing and resistance exercise, several times a week. Walking maintains bone; loaded strength work builds it.
- Adequate calcium, ideally from food. Most adults need around 1,000 to 1,200 mg per day.
- Vitamin D sufficient to maintain a serum 25-OH level in the normal range, which for many adults means 800 to 1,000 IU daily.
- Protein at roughly 1.0 to 1.2 g per kilogram of body weight, which supports both bone and the muscle that protects it.
- Fall prevention: vision correction, home hazard removal, balance training, and a medication review to identify sedatives or blood pressure drugs that increase fall risk.
Smoking and heavy alcohol use both accelerate bone loss and belong on any honest prevention list.
The strongest predictor of a future fracture is a past one. A wrist or vertebral fracture after age fifty is a screening event, not a mishap.
When medication is warranted
For those who meet treatment thresholds, bisphosphonates remain first-line for most patients and reduce vertebral fracture risk substantially in randomized trials. Denosumab, anabolic agents such as teriparatide and romosozumab, and, in selected postmenopausal women, hormone therapy each have a role. The choice depends on fracture site, severity, kidney function, and how long treatment is likely to continue.
Drug holidays after several years on a bisphosphonate are common practice and worth discussing rather than continuing indefinitely.
The bottom line
Osteoporosis is one of the more preventable causes of disability in later life, and the screening test is quick, safe, and cheap. If you are a woman approaching 65, a postmenopausal woman with risk factors, or a man over 70, ask when your first DEXA is due. If you have had a fragility fracture, ask now.