A typical 70-year-old woman can expect a T-score somewhere in the osteopenia range, roughly between −1.0 and −2.5, with most population studies placing the average around −1.5 to −2.0 at the hip. One large Italian study of women aged 65 to 75 found a mean hip femur T-score of about −2.0 and a total femur T-score of about −1.4, which gives a reasonable ballpark for this age group. But that single number hides a lot: where on the skeleton the measurement is taken, which brand of scanner is used, and your ethnic background all shift the result meaningfully, sometimes by a full standard deviation or more.
What Population Studies Actually Report
T-scores compare your bone mineral density to the peak bone mass of a healthy young adult woman, so a negative number is expected as you age. The World Health Organization classifies a T-score above −1.0 as normal, −1.0 to −2.5 as osteopenia (lower-than-normal bone density), and −2.5 or below as osteoporosis. By 70, the majority of women fall somewhere in the osteopenia zone.
In a study of over 13,000 Italian women and men, women aged 65 to 75 had a mean hip femur T-score of −1.96 and a mean total femur T-score of −1.44.1PubMed Central. Bone Mineral Density Reference Values in 18- to 95-Year-Old Population in Lombardy Region, Italy A Finnish study of home-dwelling women aged 70 to 80 found that about 36% had osteopenia, meaning their scores fell between −1.0 and −2.5.2PubMed. Sarcopenia and osteopenia among 70-80-year-old home-dwelling Finnish women: prevalence and association with functional performance These figures are not universal benchmarks but they illustrate the same pattern: most 70-year-old women cluster in the low-normal to osteopenic range at the hip, with a meaningful minority already meeting the threshold for osteoporosis.
One reason you will not find a single, definitive “average T-score for a 70-year-old woman” published by a medical authority is that T-scores were never designed to be a population average. They were designed to express how far an individual’s bone density has drifted from a young-adult reference point. The WHO thresholds are diagnostic cutoffs, not descriptions of what is typical at a given age. Still, the data consistently place the average 70-year-old woman’s hip T-score in the neighborhood of −1.5 to −2.0, depending on the skeletal site and the population studied.
Why the Measurement Site Changes the Number
Your T-score is not one number. It is a different number at every skeletal site the scanner measures, and those numbers do not always agree. A woman might have a T-score of −2.6 at the femoral neck (the narrow band at the top of the thighbone) and −1.3 at the lumbar spine, or the reverse. This phenomenon, called T-score discordance, is common. In one study of over 900 people diagnosed with osteoporosis, 40% had minor discordance between hip and spine scores, and 5% had major discordance, meaning the two sites placed them in entirely different diagnostic categories.3PubMed Central. T-score discordance between hip and lumbar spine: risk factors and clinical implications
For women over 60, the lumbar spine reading deserves particular skepticism. Osteoarthritis produces bony growths called osteophytes along the vertebrae, and these dense deposits get captured by the scanner along with actual bone. The result is an artificially inflated spine T-score that can mask real osteoporosis. Research has found that lumbar osteophytes explained roughly 17% of the variation in lumbar spine bone density in women, and that this artifact affects most people over 60.4PubMed. Effect of osteoarthritis in the lumbar spine and hip on bone mineral density and diagnosis of osteoporosis in elderly men and women Vascular calcification in the aorta, which sits right in front of the spine, can do the same thing. One case report documented a woman in her 90s whose lumbar T-score looked exceptionally high, but the reading turned out to be entirely an artifact of advanced vertebral degeneration and aortic calcification.5PubMed. Exceptionally high lumbar spine DXA T-score in a nonagenarian: an artefact of degenerative spinal changes and vascular calcification
This is why many experts recommend that osteoporosis diagnosis and fracture risk assessment in older adults rely primarily on hip bone density rather than the anteroposterior lumbar spine, unless spinal arthritis has been specifically excluded.4PubMed. Effect of osteoarthritis in the lumbar spine and hip on bone mineral density and diagnosis of osteoporosis in elderly men and women If your doctor gives you only a spine T-score and it looks reassuringly normal, it is worth asking about the hip measurement.
How the Scanner Brand Shifts Your Score
This is one of the less discussed quirks of bone density testing: two major DXA manufacturers, Hologic and Lunar (GE), use different reference populations and different statistical models to calculate T-scores, and the results do not line up. A head-to-head comparison of both machines on the same patients found that Hologic consistently produced lower values than Lunar. The mean T-score difference at the lumbar spine was about 0.74 points, and at the femoral neck the systematic gap was close to 0.9 standard deviations.6PubMed. Diagnosing (severe) Osteoporosis by Hologic vs. Lunar Measurements: A Single-Center Retrospective Study7PubMed. Discrepancies in normative data between Lunar and Hologic DXA systems
In practical terms, about half of the patients diagnosed with osteoporosis on a Hologic machine were reclassified as merely osteopenic when scanned on a Lunar device.6PubMed. Diagnosing (severe) Osteoporosis by Hologic vs. Lunar Measurements: A Single-Center Retrospective Study This does not mean one machine is right and the other wrong. It means a T-score is not an absolute measurement like a blood pressure reading. If you switch facilities and your T-score changes dramatically, the scanner brand is often the reason. For tracking bone density over time, it matters that you use the same machine and ideally the same facility each time.
Ethnic and Racial Differences in Bone Density
Standard T-scores use a reference population of young white women from a large U.S. survey. If you are not a white woman, this comparison may overstate or understate your risk. A multi-ethnic study of older women found that Afro-Caribbean women had hip and femoral neck bone density roughly 21 to 31% higher than white American women, and African American women were 13 to 23% higher. Hong Kong Chinese and South Korean women, by contrast, had total hip and spine values about 4 to 7% lower.8PubMed Central. Racial/ethnic differences in bone mineral density among older women
These differences have real diagnostic consequences. When Chinese American women were scored against the standard white reference data, their osteoporosis rates at the femoral neck appeared to be about 17%. Switching to a Chinese American-specific reference brought that number down to about 7%, and the overall osteoporosis prevalence at any site dropped from roughly 30% to 13%.9PubMed. Applying ethnic-specific bone mineral density T-scores to Chinese women in the USA Expert groups have noted that the gradient of fracture risk from bone density appears fairly similar across ethnic groups, but that the variation within any single ethnic group is actually greater than the differences between groups.10The Journal of Clinical Endocrinology & Metabolism. Ethnic Differences in Bone Mass—Clinical Implications In other words, your individual T-score matters more than your ethnicity, but the reference population used to generate that score can nudge you across a diagnostic line.
Why the T-Score Is Not the Whole Story on Fracture Risk
The uncomfortable reality is that the majority of fragility fractures happen in women whose T-scores are in the osteopenia range, not in the osteoporosis range.11PubMed Central. The assessment of fracture risk There are simply far more women with T-scores between −1.0 and −2.5 than below −2.5, so even though each individual in the osteoporosis category has higher risk, the sheer number of osteopenic women means more fractures come from that group.
This is why clinicians look beyond the T-score alone. The FRAX tool estimates your 10-year probability of a major fracture using clinical risk factors like age, prior fracture history, smoking, glucocorticoid use, and family history, in addition to bone density. Falls history, though not included in the FRAX calculation, also matters independently.12PubMed Central. Clinical risk factors, bone density and fall history in the prediction of incident fracture among men and women A 70-year-old woman with a T-score of −1.8, a previous wrist fracture, and a mother who broke her hip carries substantially more risk than a woman with the same T-score and no other risk factors.
Another tool gaining traction is the trabecular bone score, or TBS, which analyzes the texture of the spine DXA image to estimate how the internal structure of bone looks, not just how dense it is. TBS and bone density correlate only weakly with each other, suggesting they capture different aspects of bone health. In one study, roughly 73% of fractures occurred in women who did not meet the osteoporosis threshold by T-score alone. Of those women, about 72% had a low TBS, correctly flagging them as being at increased risk even though their density looked acceptable.13PubMed. Spine trabecular bone score subsequent to bone mineral density improves fracture discrimination in women TBS has since been shown to predict fractures independently of BMD across multiple clinical contexts.14PubMed Central. DXA parameters, Trabecular Bone Score (TBS) and Bone Mineral Density (BMD), in fracture risk prediction in endocrine-mediated secondary osteoporosis
When Treatment Is Recommended
A T-score of −2.5 or below at the spine, femoral neck, total hip, or one-third radius triggers a strong recommendation for medication in U.S. clinical guidelines.15Endocrine Practice. American Association of Clinical Endocrinologists and American College of Endocrinology Clinical Practice Guidelines for the Diagnosis and Treatment of Postmenopausal Osteoporosis — 2020 Update But treatment thresholds extend well into the osteopenia range. If your T-score falls between −1.0 and −2.5 and your FRAX-calculated 10-year probability of a major osteoporotic fracture is 20% or higher, or your hip fracture probability is 3% or higher, the same guidelines recommend pharmacologic therapy.15Endocrine Practice. American Association of Clinical Endocrinologists and American College of Endocrinology Clinical Practice Guidelines for the Diagnosis and Treatment of Postmenopausal Osteoporosis — 2020 Update If you have had a prior fragility fracture of the hip or spine, medication is recommended regardless of how the T-score reads.
Patients considered at “very high” fracture risk include those with very low T-scores (below −3.0), recent fractures, multiple fractures, fractures occurring despite already being on osteoporosis medication, or very high FRAX probabilities. These patients may be steered toward more aggressive initial therapies rather than the standard first-line options. The U.S. Preventive Services Task Force recommends that all women aged 65 and older be screened with bone density testing, and that younger postmenopausal women at elevated risk also be screened.16JAMA. Screening for Osteoporosis to Prevent Fractures: US Preventive Services Task Force Recommendation Statement
Treatment with denosumab, one of the more studied osteoporosis medications, has shown that fracture risk keeps dropping as the total hip T-score improves. In women who achieved a total hip T-score of −1.5 during treatment, the one-year nonvertebral fracture rate was about 2%, compared with about 3% in those whose T-score remained at −2.5. The benefit plateaus somewhere between −2.0 and −1.5, meaning pushing the T-score above that range does not buy much additional fracture reduction.17Journal of Bone and Mineral Research. Relationship Between Bone Mineral Density T-Score and Nonvertebral Fracture Risk Over 10 Years of Denosumab Treatment
The Speed of Bone Loss Is Not Constant
A common assumption is that bone just keeps eroding at the same pace after menopause. It does not. Bone loss is fastest in the years immediately following menopause and then slows considerably. In a longitudinal study, women aged 51 to 65 lost bone mineral at about five times the rate of women aged 70 to 91.18JCI Insight. Age and activity effects on rate of bone mineral loss The mechanisms also shift. Early postmenopausal bone loss is driven primarily by estrogen withdrawal, which ramps up the cells that break down bone. In later years, the loss becomes more gradual and is driven by a broader set of aging processes, including a shift in the bone marrow from producing bone-building cells to producing fat cells, which actually has a toxic effect on bone formation and mineralization.19PubMed Central. Aging and bone loss: new insights for the clinician
For a 70-year-old woman, this means that the worst of the decline has probably already happened. That does not make the current T-score irrelevant, but it does mean that a scan taken at 70 is not a snapshot of a free fall. The bone you have at 70 is relatively stable compared to the rapid changes of your 50s and early 60s, and interventions have a realistic chance of holding or even improving the score rather than just slowing a steep descent.
What the Reference Database Itself Looks Like
T-scores ultimately depend on what “peak bone mass of a young adult woman” means in practice, and that reference point is not universal. An expert group has recommended using the NHANES III database, derived from a large U.S. survey population, as the standard reference for hip T-scores. For the lumbar spine, manufacturers are allowed to use their own reference databases.20PubMed. Use of dual-energy X-ray absorptiometry (DXA) for diagnosis and fracture risk assessment; WHO-criteria, T- and Z-score, and reference databases Research has shown that country-specific reference data can produce substantially different T-scores from the NHANES III baseline, with young women in some populations scoring half a standard deviation or more above the U.S. reference.21PubMed. Country-specific young adult dual-energy X-ray absorptiometry reference data are warranted for T-score calculations in women: data from the peak-25 cohort
This is not a flaw in the system so much as a limitation to keep in mind. Your T-score is always relative to a reference, and that reference is anchored to a specific group of young women measured on specific equipment in a specific country. Two women with identical actual bone density can receive different T-scores if their scans are processed against different reference databases. If you are comparing your T-score to population averages cited in a study, it is worth knowing that the reference behind your own scan may not be the same one used in that study.
How the Gap Between Hip and Spine Scores Affects Your Risk
When the spine and hip T-scores disagree, the size of that gap itself carries prognostic information. A population-based Canadian study found that the difference between lumbar spine and femoral neck T-scores is an independent risk factor for major osteoporotic fractures, separate from what the FRAX tool calculates using the femoral neck score alone.22PubMed Central. Spine-hip T-score difference predicts major osteoporotic fracture risk independent of FRAX: a population-based report from CAMOS In practical terms, if your spine T-score is much lower than your hip score, your fracture risk may be higher than what your hip-based FRAX estimate suggests. This is one reason some guidelines now support adjusting FRAX probabilities using the spine-hip offset.
Exercise and Bone Density in the Osteopenic Range
For women with T-scores in the osteopenia range, the question of whether exercise can meaningfully change bone density gets asked constantly, and the answer is more encouraging than many people expect. A randomized controlled trial of postmenopausal women with low bone mass found that a supervised, high-intensity resistance and impact training program improved lumbar spine bone density by about 3% and femoral neck density by a small but significant amount over eight months, while the control group lost bone at both sites.23Journal of Bone and Mineral Research. High‐Intensity Resistance and Impact Training Improves Bone Mineral Density and Physical Function in Postmenopausal Women With Osteopenia and Osteoporosis: The LIFTMOR Randomized Controlled Trial The key word there is “high-intensity.” Gentle walking or light resistance bands, while good for general health, tend to be insufficient stimulus for bone.
A separate trial comparing high-intensity resistance training (around 85% of one-repetition maximum) with lower-intensity training (around 60%) confirmed that the higher-intensity protocol was more effective for improving bone density, bone mineral content, and T-scores. However, the lower-intensity protocol still managed to counteract age-related bone loss in both the femoral neck and lumbar spine, which matters for women who have joint pain, arthritis, or bones too fragile for heavy loading.24PubMed Central. High versus Low-Intensity Resistance Training on Bone Mineral Density and Content Acquisition by Postmenopausal Women with Osteopenia: A Randomized Controlled Trial Both programs showed significant improvements over 24 weeks. For a 70-year-old woman with a T-score in the −1.5 to −2.0 range, this kind of training, ideally under professional supervision for safety, is one of the few non-drug strategies with evidence behind it for actually moving the number rather than just slowing the decline.