Most women should get their first DEXA scan at age 65, and most men at age 70. But dozens of risk factors can move that timeline earlier, sometimes by decades. Your age, medications, medical history, and lifestyle all factor into whether you need screening now or can wait.
Standard Age Recommendations
The U.S. Preventive Services Task Force recommends routine bone density screening for all women 65 and older. For younger postmenopausal women, screening is recommended when their fracture risk equals or exceeds that of a 65-year-old white woman without additional risk factors. For men, the Endocrine Society recommends DEXA screening starting at age 70, or between 50 and 69 if risk factors like low body weight, prior fractures, or smoking are present.
These are baseline recommendations for people with no special risk factors. If anything in the sections below applies to you, the timeline shifts earlier.
Risk Factors That Lower the Screening Age
Certain risk factors can justify a DEXA scan as early as age 40. UCSF identifies the following as reasons for earlier screening:
- Family history of osteoporosis
- Low body weight or a history of eating disorders
- Fractures after age 50, even from minor falls
- Early menopause, whether natural or surgical
- Smoking or heavy alcohol use (three or more drinks per day over a long period)
- Rheumatoid arthritis or chronic kidney disease
- Asian or Northern European descent
- Vitamin D deficiency or insufficient calcium intake
- Sudden, significant loss of height
- Young female athletes who exercise intensely while eating too little, leading to missed periods
Other medical conditions that may prompt earlier screening include intestinal disorders that impair nutrient absorption and multiple sclerosis. If you have any combination of these risk factors, your doctor can use a tool called FRAX to estimate your 10-year fracture probability and determine whether a scan makes sense now.
Medications That Trigger Earlier Screening
Several common drug classes accelerate bone loss, and guidelines recommend a baseline DEXA scan before or shortly after starting them.
Corticosteroids like prednisone are the most well-known culprits. Taking them daily for three months or more significantly raises fracture risk, and most guidelines call for a bone density measurement or fracture risk assessment before starting long-term steroid therapy.
Aromatase inhibitors, used as hormone therapy for estrogen-receptor-positive breast cancer in postmenopausal women, suppress estrogen levels even further than menopause alone and accelerate bone loss. Professional guidelines recommend a DEXA scan for all women beginning this therapy. Similarly, hormone-suppressing drugs used for prostate cancer, endometriosis, and certain other conditions warrant bone density evaluation.
Other medications linked to bone loss include proton pump inhibitors (commonly prescribed for acid reflux), certain antidepressants, anti-seizure medications, blood thinners like heparin, and some chemotherapy drugs. If you’re on any of these long-term, it’s worth asking whether a DEXA scan is appropriate.
How the FRAX Tool Guides Decisions
FRAX is an online calculator that estimates your 10-year probability of a major osteoporotic fracture based on age, sex, weight, smoking status, alcohol use, and other clinical factors. It can be used with or without a DEXA score. In the U.S. and Canada, a 10-year major fracture probability of 20% or higher, or a hip fracture probability of 3% or higher, is the threshold for starting treatment. Some screening programs use a 15% threshold to decide who should get a DEXA scan in the first place.
Your doctor may run this calculation to determine whether you need a scan even if you haven’t reached the standard screening age.
What Your Results Mean
DEXA results are reported as a T-score, which compares your bone density to that of a healthy 30-year-old. A T-score of negative 1 or higher is normal. Between negative 1 and negative 2.5 indicates osteopenia, a milder form of bone loss. A T-score of negative 2.5 or lower suggests osteoporosis.
Your T-score also determines how soon you’ll need a follow-up scan.
When to Get a Repeat Scan
Not everyone needs frequent rescreening. Research suggests the following intervals based on your initial results:
- Normal or mild osteopenia (T-score above negative 1.5): 15 years before the next scan
- Moderate osteopenia (T-score negative 1.5 to negative 1.99): 5 years
- Advanced osteopenia (T-score negative 2.0 to negative 2.49): 1 year
Women over 80 lose bone faster, so these intervals should be shortened by about one-third in that age group. If you’re on treatment for osteoporosis, your doctor will typically repeat the scan at intervals long enough for real changes to be detectable. Small fluctuations between scans can be measurement noise rather than true bone loss, so changes generally need to exceed a few percentage points to be considered meaningful.
How to Prepare for the Scan
A DEXA scan is quick and painless, usually taking 10 to 15 minutes. You lie on a table while a low-dose X-ray arm passes over your hip and spine. There’s no enclosed space and no injection.
On the day of your scan, eat and drink normally but skip calcium supplements and antacids that morning. Wear comfortable, loose clothing without metal zippers, belts, or buttons. If you’ve had a barium study, a CT or MRI with contrast dye, or a nuclear medicine scan in the past week, wait at least seven days before scheduling your DEXA. These substances can interfere with the accuracy of the reading.