DEXA, T-scores, and the bone density decision at 50

The single most predictable trajectory of menopause is what happens to your bones — and it's also the one most women aren't told about until something breaks. Here's the actual decision tree: when to scan, how to read the number, what moves it.

Your bones don't feel different at 50. They feel exactly like they did at 30. That's the cruel part of the story — there is no warning signal. The first signs of bone density loss are usually a wrist fracture from a low fall, a vertebral compression that shows up on an unrelated x-ray, or a hip fracture that ends an independent life. By the time symptoms exist, the damage is years into the timeline.

The good news: bone density is one of the most measurable, intervenable, evidence-rich variables in midlife medicine. A single DEXA scan tells you where you are. A specific set of interventions moves the number. And the timing window for intervention is right now — your 50s and early 60s.

What a DEXA scan actually measures

DEXA (dual-energy x-ray absorptiometry) measures bone mineral density at the hip and lumbar spine using two low-dose x-ray beams. The total radiation dose is roughly 1/10th of a chest x-ray. The scan takes 10-15 minutes. Most insurance covers it once you hit certain age or risk thresholds; cash price is $100-200 if you self-pay.

You get two numbers back:

• T-score: how your bone density compares to a healthy young adult (age 30) reference. This is what gets used for diagnosis.
• Z-score: how you compare to others your age. Mainly useful for younger people or for spotting unexpectedly fast loss.

How to read your T-score

Most women 50+ will receive an osteopenia diagnosis. This is not a disease in the alarming sense — it's a statistical category. But it's the inflection point at which intervention has the most leverage.

When to get scanned

• Routine baseline at 65 per most guidelines (USPSTF, ACOG)
• Earlier — at 50-65 if you have any risk factor: family history of osteoporosis or hip fracture, low body weight (BMI under 21), corticosteroid use, smoking history, alcohol use over 3 drinks/day, prior fragility fracture as an adult, or rheumatoid arthritis
• At menopause (any age) if you went through it before 45 (early menopause is itself a major risk factor)
• Repeat scans every 2-3 years if you're being followed for osteopenia or treated for osteoporosis. More frequent doesn't improve outcomes and adds cost.

What actually moves bone density at midlife

Strength training — most underrated intervention

The most cited intervention in the bone density literature is also the one most women aren't doing enough of. Mechanical loading triggers osteoblast activity (bone-building cells). The protocol that has the best evidence base: progressive resistance training, 2-3x/week, targeting major compound movements (deadlift, squat, overhead press, row, hip thrust), with weight heavy enough that the last 2-3 reps of each set are genuinely difficult.

The LIFTMOR trial (2018, Watson et al.) showed that supervised heavy resistance training in postmenopausal women with osteopenia increased femoral neck bone mineral density by 0.3-0.6% per year — meaningful, sustained, and at intensity levels (5RM lifts) most older-women fitness advice still treats as off-limits.

Bodyweight movement, walking, yoga, Pilates — all valuable for general health but produce minimal-to-no bone density change. The mechanical load isn't there. To move the DEXA number you need actual weight on the bar.

HRT — the bone density use case

Estrogen is the dominant regulator of bone remodeling in women. Its decline at menopause directly drives the rapid bone loss seen in the first 5-7 years post-menopausal. HRT preserves bone density and is FDA-approved specifically for postmenopausal osteoporosis prevention in women at significant risk.

The 2022 and 2023 reanalyses of the WHI HRT data clarified that for women within 10 years of menopause and without contraindications, the bone-preserving benefit substantially outweighs the marginally elevated risks for most. See our HRT post-WHI letter for the full reanalysis context.

Calcium + vitamin D — table stakes, not heroic

Adequate calcium intake (1,000-1,200 mg/day total, food + supplement) and vitamin D (1,000-2,000 IU/day, more if deficient) are necessary but not sufficient. They prevent acceleration of loss; they don't reverse it. Most women already get enough calcium from diet; supplementation matters mainly if dairy intake is low. Vitamin D should be checked via your annual bloodwork (target 40-60 ng/mL).

Pharmacological — when DEXA crosses into osteoporosis range

Bisphosphonates (alendronate, zoledronic acid) reduce fracture risk by 30-50% in osteoporosis. Newer agents like denosumab (Prolia, twice-yearly injection) and romosozumab (Evenity, for severe cases) have stronger effects on bone-building specifically. These are not first-line for osteopenia — they're for actual osteoporosis diagnosis.

The decision tree, summarized

1. Get the DEXA. Now or at your next physical.
2. If normal: re-scan every 5 years. Start strength training anyway — prevention beats reversal.
3. If osteopenia: strength training is your primary intervention. Consider HRT discussion with your prescriber if you're peri-/early-post-menopausal and otherwise a candidate. Calcium + vitamin D adequate. Re-scan in 2-3 years.
4. If osteoporosis: pharmacological treatment is the conversation to have. Strength training continues. HRT is more strongly indicated if you're a candidate.

What this letter doesn't replace

This is informational, not diagnostic. The specifics of your situation — family history, medication interactions, fracture risk score (FRAX is the tool clinicians use, freely available) — change the math. Bring your DEXA results and this article to your prescriber and have the conversation.

After Forty Feel is independent editorial. Reader-funded. Some links are affiliate links — disclosed when present. No supplement-brand or pharmaceutical-brand sponsorships, ever. This letter is informational and not a substitute for medical advice.