Study Links Weakened Bones to Accelerated Brain Aging

The findings, reported in a study published in the journal Radiology, revealed an association between weakened bones and signs of accelerated brain aging, including changes in white matter structure and more rapid cognitive decline.

“This study represents the first longitudinal secondary analysis linking baseline vertebral bone mineral density to changes in white matter structure, the progression of hypertensive white matter changes, and cognitive function,” says Shadpour Demehri, a radiologist at Johns Hopkins University. “This comprehensive study, which used both imaging techniques and clinical assessments, clearly demonstrates that baseline bone density is associated with both functional measures and imaging markers of age-related brain degeneration.”

The study included 715 participants whose data had been collected as part of a long-term health research project. In addition to chest scans, the participants underwent tests of thinking and memory. Several years after the initial assessments, brain scans and additional cognitive tests were conducted, Planet Today reports.

To obtain bone mineral density (BMD) measurements from chest CT scans, the researchers used a specially developed artificial intelligence algorithm. Bone mineral density measures the amount of minerals, such as calcium, present in bone. The lower the mineral content, the weaker the bone and the greater the risk of fracture.

“Diagnostic images contain a wealth of data that AI can now synthesize at scale across multiple organ systems,” Demehri says. “This creates a powerful, newly emerging opportunity to connect coexisting age-related pathologies that have traditionally been studied in isolation, as well as to identify shared biological pathways and potentially common causal mechanisms.”

In some brain regions, lower bone mineral density was associated with a greater number of hypertensive white matter lesions. These appear as bright spots on scans and indicate damaged tissue. Lower bone mineral density was also associated with fractional anisotropy measurements in other white matter regions, indicating poorer structural integrity of the brain.

Previous research has established that the brain regions in which these signs of damage were detected are associated with executive function, working memory, and attention. More rapid declines in cognitive test scores were also correlated with lower bone mineral density. However, the researchers emphasize that there is insufficient evidence to conclude that weakened bones cause cognitive decline. They consider it more likely that another factor contributes to both conditions.

“This study is not about causation, but about observing a metabolic syndrome that may cause degeneration in both bone and brain,” Demehri says. “The overlap observed in the study may reflect shared metabolic factors associated with aging, including insulin resistance, dyslipidemia, and menopausal changes, rather than a direct effect of bones on the brain.”

The fact that participants were followed for several years is a strength of the study. However, longer-term research will be needed to determine whether the accelerated brain aging observed in this study ultimately leads to diagnosed health conditions such as dementia.

One potential application of these findings is identifying people at increased risk of cognitive impairment and related conditions based on their bone mineral density measurements. However, substantially more data must be collected and analyzed before such predictions can be made.

The study also demonstrates that, with relatively little additional training and AI-assisted analysis, vast quantities of existing medical data can be used to generate valuable new insights.

“Chest CT scans are performed for lung cancer screening, calcium scoring, nodule surveillance, and many other indications,” says Sarah Momtazmanesh, a radiologist at Johns Hopkins University. “These scans may provide an opportunity to measure bone mineral density in the thoracic spine, which is associated with cognitive decline.”