Stroke Leaves Hidden Fingerprints in Bone, Landmark Scan Study Reveals

More than 100 million people worldwide are living as survivors of ischemic stroke, a number that continues to climb as societies age and stroke mortality declines. Yet surviving the brain attack is only the beginning of a longer struggle. Research has long shown that patients who experience an ischemic stroke or a transient ischemic attack face a dramatically elevated risk of fractures, with reported rates ranging from 22 to 74 fractures per 1000 person-years and a hip fracture risk up to seven times that of the general population. The danger peaks in the first year after the event and gradually subsides, but strikingly, fracture risk is also elevated in the year before the stroke occurs, hinting that something deeper than immobility alone is damaging the skeleton. Scientists call this phenomenon post-stroke osteopathy, and its underlying mechanisms have remained stubbornly obscure.

A new study published in Archives of Osteoporosis now offers the most detailed portrait yet of what happens to bone in the immediate aftermath of a cerebral ischemic event. In the baseline analysis of the Post-stroke Osteopathy study, a team led by researchers at the Medical University of Innsbruck in Austria combined high-resolution peripheral quantitative computed tomography, or HR-pQCT, with an extensive panel of biochemical bone markers in a cohort of acute stroke and TIA patients. According to the investigators, this is the largest cohort of ischemic stroke or TIA patients ever examined prospectively with HR-pQCT and the first study anywhere to correlate bone biomarkers with high-resolution imaging parameters in this clinical setting.

The imaging technique at the heart of the study represents a major leap beyond conventional bone assessment. Dual-energy X-ray absorptiometry, the workhorse of osteoporosis screening, measures bone mass in two dimensions and misses critical information about bone quality. HR-pQCT, by contrast, resolves the three-dimensional microarchitecture of cortical and trabecular bone at peripheral sites such as the distal radius and distal tibia with an impressive 61-micrometer voxel size and very low radiation exposure. This matters because bone strength depends not merely on how much mineral bone contains but on its morphology and microstructure, a fact convincingly established by large international consortia showing that cortical and trabecular microarchitecture independently predict fracture risk in older women and men.

In the study, 122 participants were enrolled between March 2021 and May 2022 at the University Hospital Innsbruck as a pilot sub-study of the ongoing STROKE-CARD Registry. Of these, 116 underwent baseline HR-pQCT imaging of all four extremities within days of their event, with a median age of 71.5 years and 26.7 percent women. Neurological deficits were predominantly mild, reflected by a median National Institutes of Health Stroke Scale score of 2, and scans were performed on average 5.4 days after admission. Blood samples for biomarker analysis were drawn in 62 patients a mean of 3.0 days after admission and analyzed using validated enzyme-linked immunosorbent assays for osteocalcin, C-telopeptide of crosslinked collagen type 1, sclerostin, osteoprotegerin, soluble RANKL, and periostin.

The imaging results revealed clear patterns. Women in the cohort had lower total, cortical, and trabecular volumetric bone mineral density, along with lower values for nearly every other HR-pQCT parameter, in both the upper and lower extremities. This finding mirrors what has been documented in healthy reference populations, suggesting that stroke patients retain normal sex-based differences in bone structure. Increasing age was associated with lower total and cortical volumetric bone mineral density, but intriguingly, trabecular parameters showed no relationship with age in this cohort, a dissociation the authors suggest may be linked to higher sclerostin levels in elderly patients, which correlated with stable trabecular architecture.

Lifestyle and metabolic factors left their own signatures on the skeleton. Active or former smokers had lower total and trabecular volumetric bone mineral density in the tibia but not in the radius, consistent with prior evidence that smoking exerts a particularly strong influence on the trabecular compartment. Higher body mass index was associated with greater cortical and trabecular bone areas and higher trabecular density, especially in the radius. The weaker BMI effect in the tibia, a weight-bearing bone where mechanical loading might be expected to matter most, prompted the authors to argue that BMI captures complex systemic processes rather than simple mechanical loading, with detrimental lipotoxic and metabolic pathways potentially counteracting the localized benefits of extra weight at the lower limb.

The biomarker correlations provided some of the most novel insights of the analysis. Sclerostin, a protein secreted by osteocytes that suppresses bone formation, showed a positive correlation with trabecular HR-pQCT parameters, including trabecular volumetric bone mineral density in both the radius and the tibia, an association never before examined in a stroke or TIA population. Higher osteoprotegerin levels were linked to lower cortical area and thickness, echoing findings from the STRAMBO study of men, which similarly showed that elevated osteoprotegerin selectively affects the cortical rather than the trabecular compartment. Osteocalcin, a marker of bone turnover, correlated negatively with total volumetric bone mineral density and cortical thickness in the radius, in line with prior studies linking higher osteocalcin to increased bone turnover and skeletal fragility.

Notably, several traditional cardiovascular risk factors failed to leave any measurable trace on the skeleton in this cohort. No correlation was found between any HR-pQCT parameter and diabetes mellitus, blood pressure, or dyslipidemia, and neither stroke severity at admission nor stroke etiology, classified according to the TOAST criteria, was associated with imaging or biomarker outcomes. When the 17 patients with TIA were excluded to focus on confirmed strokes, the findings remained unchanged, reinforcing the robustness of the observed patterns. Overall, the biochemical markers exerted more influence on bone parameters in the radius than in the tibia, an asymmetry that future longitudinal follow-up may help explain.

The authors are candid about the limitations of their work. The cohort was recruited at a single center, all participants were of European descent, women were underrepresented owing to eligibility criteria such as the exclusion of patients with known osteoporosis, and HR-pQCT measurements were confined to peripheral skeletal sites that may not fully reflect changes in the axial skeleton. The acute phase after stroke may itself perturb biomarker levels, baseline blood sampling was not feasible in all patients, and the exploratory correlation analyses, involving many comparisons without formal adjustment for multiple testing, warrant cautious interpretation. The absence of an in-house, age-matched healthy control group further means the baseline findings describe the absolute bone status of acute patients rather than stroke-specific deviations.

Even so, the study establishes a crucial foundation. By pairing the finest available in vivo images of bone microstructure with a comprehensive biochemical profile gathered within days of a cerebral ischemic event, the Innsbruck team has created the reference point against which future bone loss after stroke can be measured. The prospective design of the Post-stroke Osteopathy study, with follow-up imaging and blood sampling at 3, 6, and 12 months, promises to chart the trajectory of skeletal deterioration and to clarify whether the biomarker signals identified at baseline predict which patients will go on to suffer the devastating fractures that raise mortality and erode quality of life after stroke. If those predictions hold, routine bone microarchitecture screening and early targeted intervention could become standard components of post-stroke care.

Subject of Research: Bone microarchitecture and biomarker characteristics in patients after ischemic stroke or transient ischemic attack assessed with HR-pQCT imaging

Article Title: High-resolution peripheral quantitative computed tomography imaging and bone biomarker characteristics of patients with ischemic stroke or transient ischemic attack—baseline analysis of the Post-stroke Osteopathy study

Article References: Dejakum, B., Bereiter-Payr, J., Felicetti, S., Moelgg, K., Karisik, A., Degenhart, G., Toell, T., Boehme, C., Mayer-Suess, L., Pechlaner, R., Liphardt, A.-M., Berg, G., Schett, G., Kiechl, S., & Knoflach, M. (2026). High-resolution peripheral quantitative computed tomography imaging and bone biomarker characteristics of patients with ischemic stroke or transient ischemic attack—baseline analysis of the Post-stroke Osteopathy study. Archives of Osteoporosis, 21(1), Article 134. https://doi.org/10.1007/s11657-026-01767-w

Image Credits: AI Generated

DOI: 10.1007/s11657-026-01767-w

Keywords: ischemic stroke, transient ischemic attack, HR-pQCT, bone microarchitecture, post-stroke osteopathy, bone biomarkers, osteoporosis, fracture risk, sclerostin, osteoprotegerin, osteocalcin, volumetric bone mineral density