As time passes in our lives, various inevitable trends become noticeable, including the weakening of our bones and the slowing of our brains.
But could one actually be an indicator of the other?
Researchers led by a team from Johns Hopkins University (JHU) in the United States studied the relationship between low bone mineral density (BMD) in the spine and signs of cognitive decline, including two markers of brain damage that show up on scans.
The results showed, as reported in a study carried out in Radiologyan association between weaker bones and signs of more rapid brain aging, including changes in white matter structure and a faster rate of cognitive decline.
“This study is the first longitudinal secondary analysis linking baseline spinal bone mineral density to changes in white matter structure, progression of white matter hyperintensity, and cognition,” says JHU radiologist Shadpour Demehri.
“This comprehensive study using both imaging and clinical assessments sends a clear signal that bone density at baseline is associated with functional and imaging measures of age-related brain degeneration.”
The study involved a total of 715 participants, whose data had already been collected as part of a long-term health research project. In addition to the chest scans, these people had taken thinking and memory tests, which were followed by brain scans and other cognitive tests several years after the first batch.
To obtain BMD readings from chest CT scans, researchers deployed a specially developed AI algorithm. Bone density refers to the presence of minerals such as calcium. If there is less of it in the bone, it becomes weaker and more likely to break.
“Diagnostic images contain an immense amount of data that AI can now synthesize at scale across multiple organ systems,” Demehri explains.
“This creates a robust and newly feasible opportunity to interconnect coexisting age-related pathologies that have traditionally been studied in isolation and identify shared biological pathways and potential common causal mechanisms.”
In some brain regions, lower BMD was linked to more white matter hyperintensities, which appear as bright spots on scans and highlight damaged tissue.
Lower BMD was also associated with fractional white matter anisotropy in other areas – an indicator of weaker brain structure.
The parts of the brain where these signs of damage have been spotted have previously been linked to executive functioning (overall organization), working memory and attention.
A more rapid decline in thinking test scores is also correlated with a decrease in BMD.
The researchers are keen to point out that there isn’t enough evidence here to suggest that weaker bones cause cognitive decline, and it’s more likely that another factor is involved in both.
“This study is not about cause and effect, but rather about observing a metabolic syndrome that can cause both bone and brain degeneration,” says Demehri.
“The co-occurrence observed in the study may reflect common metabolic factors of aging, including insulin resistance, dyslipidemia and menopausal change, rather than a direct bone-brain effect.”
The fact that the individuals were followed for several years is a credit to the study, but longer-term research will be needed to see whether the more rapid brain aging seen here actually translates into diagnosed health problems such as dementia.
One way this data could be used is to screen people at higher risk of cognitive decline and associated diseases, based on their BMD values. However, much more data will need to be collected and analyzed before such predictions can be made.
What the research also shows is that with a little extra training and AI-powered review, vast amounts of existing medical data can be leveraged to reveal new insights.
“Chest CT scan is performed for lung cancer screening, calcium assessment, nodule tracking and many other indications,” says radiologist Sara Momtazmanesh of JHU.
“These scans could provide an opportunistic measure of thoracic spine bone density associated with loss of cognitive function.”
The research was published in Radiology.
Gn Health
