BMD change

When you get a follow-up bone density scan, the report compares your new numbers to your last scan and calculates a percent change, usually at the lumbar spine and total hip or femoral neck. Because DXA machines have measurement variability, small changes aren't always meaningful — this is where "Least Significant Change" matters. A result has to exceed that threshold for your clinic's specific machine before it's considered a real change rather than noise.

How much change to expect depends heavily on what's driving it. Without treatment, bone density in people prone to loss often drifts down slightly each year. Some research has looked at structured resistance training programs and found modest changes in spine bone density, though effects at the hip tend to be smaller, and exercise is not a substitute for medical treatment of osteoporosis. Medications used for osteoporosis — including bisphosphonates, denosumab, teriparatide, and romosozumab — are generally associated with larger measured BMD increases in clinical trials, though trial populations and starting bone density differ, so these numbers aren't a simple apples-to-apples comparison.

It's worth remembering that BMD change is just one piece of the picture — bone quality, fall risk, and fracture history matter too. If your repeat scan shows a change (up, down, or flat), that's information for a conversation with your prescriber about whether your current approach, whether medication, lifestyle, or both, still makes sense. Decisions about starting, stopping, or switching treatment should always be made with your doctor.