DEXA (dual-energy X-ray absorptiometry) is a low-radiation X-ray scan that measures bone mineral density (BMD). Procedure: lie flat on padded table; scanner arm passes over body without touching; X-rays measure bone density at standard sites (lumbar spine and hip most commonly; sometimes forearm or whole body); takes 10-30 minutes total; very low radiation (less than chest X-ray). Results: T-score (compared to healthy young adult — used to diagnose osteoporosis): normal greater than -1.0; osteopenia (low bone mass) -1.0 to -2.5; osteoporosis -2.5 or below. Z-score (compared to age-matched peers — used in younger adults, children). FRAX tool: combines BMD with clinical risk factors to estimate 10-year fracture probability. Uses: diagnose osteoporosis; assess fracture risk; monitor response to osteoporosis treatment; baseline before glucocorticoid therapy. Standard guidelines apply with diabetes adding to risk factors. USPSTF/NOF recommendations: all women age 65+ — routine screening; men age 70+ — routine screening; younger postmenopausal women (50-64) with risk factors — screen; men 50-69 with risk factors — screen. Risk factors include: history of fracture as adult, family history of osteoporosis or hip fracture, low body weight, smoking, alcohol excess, glucocorticoid use, certain medications (aromatase inhibitors, GnRH agonists), various conditions. Diabetes considerations: type 1 diabetes — higher fracture risk; consider earlier screening (age 50 for postmenopausal women); type 2 diabetes — fracture risk modestly elevated despite often normal DEXA; standard screening intervals usually appropriate; long-standing diabetes complications (neuropathy, retinopathy, vascular disease) increase fall risk; certain diabetes medications affect bone — thiazolidinediones (pioglitazone) increase fracture risk; SGLT2 inhibitors mixed evidence (canagliflozin initially flagged but later studies less concerning). The paradox: type 2 diabetes adults often have NORMAL or HIGHER bone mineral density on DEXA but 50-100% increased fracture risk. Possible explanations: bone QUALITY (not quantity) — diabetic bone has abnormal collagen crosslinks; advanced glycation end products (AGEs) accumulate in bone matrix; bone is more brittle despite normal density. Increased fall risk — neuropathy (peripheral and autonomic — affecting balance, postural blood pressure); retinopathy (vision impairment); cardiovascular disease; medications causing hypoglycemia (which causes falls); polypharmacy. Slower bone turnover — diabetes may suppress bone formation more than resorption. Vascular changes affecting bone perfusion. Trabecular bone score (TBS) — texture measurement from DEXA — often abnormal in diabetes even with normal BMD; helps identify diabetes-related bone fragility. Vitamin D deficiency more common. Some diabetes medications affect bone (thiazolidinediones especially). Type 1 diabetes shows both low BMD AND increased fracture risk — different mechanism (insulin deficiency affects bone formation since childhood/adolescence).
DEXA Score Interpretation
| T-score | Diagnosis |
|---|---|
| Greater than -1.0 | Normal |
| -1.0 to -2.5 | Osteopenia (low bone mass) |
| -2.5 or below | Osteoporosis |
| -2.5 or below + fracture | Severe osteoporosis |
Screening Recommendations
| Population | Recommendation |
|---|---|
| Women 65+ | Routine DEXA screening |
| Men 70+ | Routine DEXA screening |
| Women 50-64 with risk factors | Screen |
| Men 50-69 with risk factors | Screen |
| Glucocorticoid use (3+ months) | Baseline DEXA |
| Adult fragility fracture | DEXA |
| Type 1 diabetes | Consider earlier (discuss with provider) |
Diabetes and Fracture Risk Paradox
- Type 2 diabetes — often NORMAL or HIGH bone density.
- BUT 50-100% increased fracture risk.
- Cause: bone QUALITY abnormal (not quantity).
- Advanced glycation end products (AGEs) make bone brittle.
- Increased fall risk from neuropathy, retinopathy.
- Hypoglycemia from medications causes falls.
- Vascular disease affects bone perfusion.
- Slower bone formation.
- Trabecular bone score (TBS) — texture measure — often low.
- Type 1 diabetes — lower BMD AND higher fractures.
Diabetes Medications and Bone
- Thiazolidinediones (pioglitazone) — increase fracture risk, especially in women.
- SGLT2 inhibitors (canagliflozin) — initially flagged; later studies less concerning.
- Metformin — neutral; possible mild bone protection.
- Sulfonylureas — hypoglycemia → fall risk.
- Insulin — hypoglycemia → fall risk.
- DPP-4 inhibitors — neutral.
- GLP-1 agonists — neutral or possibly beneficial.
- Discuss with prescriber if osteoporosis present.
Fall Prevention for Adults with Diabetes
- Address vision changes (annual eye exam).
- Manage neuropathy and balance issues (physical therapy).
- Avoid hypoglycemia (medication review).
- Home safety: remove rugs, install grab bars, improve lighting.
- Strength and balance exercise (tai chi, yoga).
- Adequate vitamin D and calcium.
- Medication review (orthostatic hypotension, sedatives).
- Address foot pain promptly.
- Appropriate footwear.
- Cane or walker if balance issues.
- Annual fall risk assessment.
The Bottom Line
DEXA (dual-energy X-ray absorptiometry) is a low-radiation X-ray scan that measures bone mineral density (BMD). Procedure: lie flat on padded table; scanner arm passes over body without touching; X-rays measure bone density at standard sites (lumbar spine and hip most commonly; sometimes forearm or whole body); takes 10-30 minutes total; very low radiation (less than chest X-ray). Results: T-score (compared to healthy young adult — used to diagnose osteoporosis): normal greater than -1.0; osteopenia (low bone mass) -1.0 to -2.5; osteoporosis -2.5 or below. Z-score (compared to age-matched peers). FRAX tool: combines BMD with clinical risk factors to estimate 10-year fracture probability. Uses: diagnose osteoporosis; assess fracture risk; monitor response to osteoporosis treatment; baseline before glucocorticoid therapy. Standard guidelines apply with diabetes adding to risk factors. USPSTF/NOF recommendations: all women age 65+ — routine screening; men age 70+ — routine screening; younger postmenopausal women (50-64) with risk factors — screen; men 50-69 with risk factors — screen. Diabetes considerations: type 1 diabetes — higher fracture risk; consider earlier screening; type 2 diabetes — fracture risk modestly elevated despite often normal DEXA; standard screening intervals usually appropriate; long-standing diabetes complications (neuropathy, retinopathy, vascular disease) increase fall risk; certain diabetes medications affect bone — thiazolidinediones (pioglitazone) increase fracture risk. The paradox: type 2 diabetes adults often have NORMAL or HIGHER bone mineral density on DEXA but 50-100% increased fracture risk. Possible explanations: bone QUALITY (not quantity) — diabetic bone has abnormal collagen crosslinks; advanced glycation end products (AGEs) accumulate in bone matrix; bone is more brittle despite normal density. Increased fall risk — neuropathy, retinopathy, cardiovascular disease, hypoglycemia from medications, polypharmacy. Slower bone turnover. Vascular changes affecting bone perfusion. Trabecular bone score (TBS) — texture measurement from DEXA — often abnormal in diabetes even with normal BMD. Vitamin D deficiency more common. Type 1 diabetes shows both low BMD AND increased fracture risk. Procedure: no special diet or fasting; avoid calcium supplements 24 hours before; wear loose clothing without metal on torso; lie on padded scan table; arm of scanner moves over body; technologist positions body for spine and hip scans; total scan time 10-30 minutes; no contact with body; no pain. Results: usually within 1-3 days; T-score and Z-score reported; FRAX 10-year fracture risk often calculated. Fall prevention important: address vision changes; manage neuropathy and balance issues; avoid hypoglycemia; home safety modifications; strength and balance exercise; adequate vitamin D and calcium; medication review; appropriate footwear. For adults with diabetes — discuss bone health with provider, address modifiable risk factors, follow standard DEXA screening guidelines plus diabetes-specific considerations. See our broader prediabetes detection guide.
