Most DEXA reports show both numbers. The T-score is the main one to focus on if you are a woman over 50 or a man over 50. In younger adults, the Z-score is more meaningful.
Your DEXA report will usually have a table with rows for each measured site (Lumbar Spine, Total Hip, Femoral Neck) and columns including "BMD" (the actual density number), "T-score," and "Z-score." Enter the T-score column values above. The T-score is always a number with a decimal point, usually negative (like -1.8 or -2.4).
If you only see one T-score on your report, that's fine. Enter what you have. If your report uses a different format or you are unsure which number to use, ask your doctor or radiologist.
No, it does not. Osteoporosis means your bones are weaker and your fracture risk is elevated, but risk is not the same as certainty. Studies from large population cohorts show that even among people with osteoporosis, most do not experience a fracture in any given year.[1] The goal of treatment is to push that risk down further, not to guarantee you will never break a bone.
What matters most is taking practical steps: talking to your doctor about whether medication is right for you, getting enough calcium and vitamin D, staying active, and reducing your risk of falls. Falls are involved in the majority of hip fractures,[2] so fall prevention is genuinely as important as your T-score.
[1] Kanis JA et al. Osteoporos Int. 2001;12(5):417-427. [2] Parkkari J et al. Calcif Tissue Int. 1999;65(3):183-187.
Not necessarily. Every DEXA machine has a natural margin of measurement error, and the International Society for Clinical Densitometry (ISCD) has established the concept of the Least Significant Change (LSC): the minimum change needed to be confident that what you are seeing is real bone loss rather than machine variability. At the spine, that threshold is typically around 2-4%; at the hip, around 3-6%.[3]
Bone density also changes slowly under normal circumstances. If you are on osteoporosis medication, a stable result or modest improvement over 1-2 years is considered a treatment success.[4] Ask your doctor specifically whether any change you see exceeds the LSC for your scanning machine.
[3] Shepherd JA et al. J Clin Densitom. 2015;18(3):372-384. (ISCD Official Positions) [4] LeBoff MS et al. Osteoporos Int. 2022;33(10):2049-2102.
The spine and hip do lose bone at different rates, so some discrepancy between the two is common. However, a lumbar spine T-score that is notably lower than the hip can sometimes be caused by degenerative joint disease (osteoarthritis), aortic calcification, or compression fractures. These conditions add density to the scan image, making the spine appear stronger than it actually is.[5]
The ISCD guidelines specifically flag this as a potential artifact and recommend that the clinician reviewing your scan check the actual scan image, not just the number.[3] If you notice this discrepancy on your report, raise it with your doctor. It is a useful conversation to have, and it affects which T-score should be used for your diagnosis and fracture risk calculation.
[3] Shepherd JA et al. J Clin Densitom. 2015;18(3):372-384. [5] Leib ES et al. J Clin Densitom. 2004;7(1):1-66.
Usually not straight away. Osteopenia is extremely common: around 43% of postmenopausal women in the United States have low bone mass without meeting the threshold for osteoporosis.[6] The majority of people with osteopenia do not fracture and do not require bone-protecting medication.
The decision about whether to treat depends on your overall fracture risk, not the T-score alone. Your doctor will typically use a validated tool called FRAX, developed by the WHO Collaborating Centre at the University of Sheffield, which combines your T-score with other risk factors to produce a 10-year fracture probability.[7] In the United States, the Bone Health and Osteoporosis Foundation recommends treatment if that probability exceeds 20% for a major fracture or 3% for a hip fracture.[4]
If your FRAX score is below those thresholds, lifestyle measures are usually the right starting point, with a repeat scan in 1-2 years to monitor trends.
[4] LeBoff MS et al. Osteoporos Int. 2022;33(10):2049-2102. [6] Wright NC et al. J Bone Miner Res. 2014;29(11):2520-2526. [7] Kanis JA et al. Osteoporos Int. 2008;19(4):385-397.
The right interval depends on your current results and risk level. The Bone Health and Osteoporosis Foundation and the ISCD offer the following general guidance:[3,4]
- On osteoporosis treatment: every 1-2 years initially, then less often once stable
- Osteopenia, monitoring without medication: every 1-2 years
- Normal bone density, low risk: every 2-5 years, or even less frequently
- On long-term glucocorticoids (steroids): annually, or at initiation of therapy
These are general guidelines, not rules. Your doctor will tailor the timing to your situation, particularly if your risk factors change or you start a new medication.
[3] Shepherd JA et al. J Clin Densitom. 2015;18(3):372-384. [4] LeBoff MS et al. Osteoporos Int. 2022;33(10):2049-2102.
Quite a lot, actually. The evidence for the following is robust:
- Calcium: Adults over 50 need around 1,200 mg per day from food and supplements combined. Dairy, leafy greens, and fortified foods count toward this total. Supplements fill the gap.[4]
- Vitamin D: A minimum of 800-1,000 IU per day is recommended for adults at risk of deficiency, which includes most older adults. Vitamin D is essential for calcium absorption.[8]
- Exercise: Weight-bearing exercise (walking, dancing, stair climbing) and resistance training (weights, resistance bands) both directly stimulate bone formation and reduce fracture risk. A 2011 meta-analysis found exercise significantly improved bone density at the spine and hip.[9]
- Quit smoking: Smokers have substantially higher fracture risk. A meta-analysis of 59 studies found current smokers had a 25% higher risk of any fracture compared to non-smokers.[10]
- Limit alcohol: Drinking three or more units per day is associated with a 70% increase in hip fracture risk compared to non-drinkers.[11]
- Fall prevention: Since falls trigger the majority of osteoporotic fractures, reducing fall risk is just as important as improving bone density. Balance training, reviewing medications that cause dizziness, and home safety checks (removing rugs, adding grab rails) all help.[2]
[2] Parkkari J et al. Calcif Tissue Int. 1999;65(3):183-187. [4] LeBoff MS et al. Osteoporos Int. 2022;33(10):2049-2102. [8] Holick MF et al. J Clin Endocrinol Metab. 2011;96(7):1911-1930. [9] Howe TE et al. Cochrane Database Syst Rev. 2011;(7):CD000333. [10] Kanis JA et al. Osteoporos Int. 2005;16(2):155-162. [11] Kanis JA et al. Osteoporos Int. 2005;16(7):737-742.