Body mass index (BMI), a simple calculation based on a person’s weight and height, may hold clues about the early stages of cognitive decline.
A recent study by researchers at Karolinska Institutet found that a noticeable drop in BMI begins about seven years before a diagnosis of mild cognitive impairment (MCI), a condition often seen as an early stage of Alzheimer’s disease or other dementias.
The study analyzed long-term changes in BMI among 1,390 adults with an average age of 78.4 years, most of whom were women (76.5%). Researchers compared the BMI trajectories of people who remained cognitively healthy with those who developed MCI.
They discovered that BMI started to decline earlier and more rapidly in those who eventually developed MCI, compared to those who stayed cognitively intact.
What the Study Found
Key findings of the study include:
Early BMI Decline: People who developed MCI showed lower BMI levels starting about seven years before their diagnosis. This suggests that weight loss may be one of the early physical changes associated with cognitive impairment.
Progression to Dementia: The rate of BMI decline did not vary significantly between those with MCI who later progressed to dementia and those who did not. This implies that the early drop in BMI is tied more to the onset of MCI than to the progression to dementia.
Autopsy Insights: In a subgroup of 358 participants who had brain autopsies, BMI decline was more pronounced in those with high levels of Alzheimer’s disease pathology or vascular damage in the brain. This finding suggests that changes in BMI could be linked to underlying brain changes.
Understanding the Link Between BMI and Brain Health
The study points to the possibility that the processes driving cognitive decline, such as Alzheimer’s disease or vascular damage, may also affect metabolism and body weight.
It’s not yet clear why this happens, but the research suggests that changes in BMI could serve as a potential early warning sign for cognitive issues.
Further studies, particularly those using advanced imaging techniques like positron emission tomography (PET), are needed to better understand the relationship between BMI changes and the buildup of harmful proteins or damage in the brain.
These future studies could clarify how early BMI decline fits into the timeline of Alzheimer’s disease and other dementias.
Practical Implications
These findings highlight the importance of monitoring weight changes in older adults. While a drop in BMI can have many causes, significant or unexplained weight loss could warrant further evaluation, particularly for older individuals who may be at risk for cognitive decline.
The study offers valuable insights into the connection between physical and cognitive health, suggesting that the body’s changes might provide early signals of what’s happening in the brain.
As researchers continue to uncover the links between BMI and cognitive impairment, these findings could eventually lead to new ways of identifying and addressing early signs of dementia.
If you care about brain health, please read studies about how the Mediterranean diet could protect your brain health, and blueberry supplements may prevent cognitive decline.
For more information about brain health, please see recent studies about antioxidants that could help reduce dementia risk, and Coconut oil could help improve cognitive function in Alzheimer’s.
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