Body mass index (BMI) has long been studied for its association with various health conditions, but its relationship with cognitive function and Alzheimer’s disease (AD) biomarkers remains inconclusive. A recent study aimed to clarify the link between BMI, cognitive status, and key Alzheimer’s biomarkers, including Aβ42 and pTau, in elderly individuals. The study drew upon data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database to explore these relationships across cognitively normal (CN) individuals and those with cognitive impairment (CI), including mild cognitive impairment (MCI) and mild dementia.
Figure 2: The effect of body mass index on hippocampal volume and MMSE score in the cognitive impairment group. MMSE score has been z-transformed. The definition of A positive was based on the A PET. The linear models were adjusted for the FHS1 score.
The researchers found that in individuals with CI, a higher BMI was associated with better cognitive performance, as measured by the Mini-Mental State Examination (MMSE), as well as higher levels of Aβ42 and larger hippocampal volume (HV). Interestingly, higher BMI was linked to a lower ratio of pTau to Aβ42, suggesting that increased body mass may be associated with a reduced pathological burden of AD in individuals with cognitive impairment.
Conversely, in cognitively normal individuals, a higher BMI was linked to worse memory performance and higher levels of pTau, indicating that the relationship between BMI and AD biomarkers may differ depending on cognitive status. The study also highlighted the role of vascular factors, such as diastolic blood pressure, in mediating the effects of BMI on cognition and brain volume, particularly in individuals with cognitive impairment.
These findings suggest that BMI plays a complex and variable role in cognitive health and the development of AD-related pathologies. In clinical practice, monitoring and managing BMI in elderly patients, particularly those with cognitive impairment, may be critical for optimizing cognitive outcomes and potentially slowing the progression of Alzheimer’s disease.
Journal article: Li Q, et al. 2024. The Association of Body Mass Index with Cognition and Alzheimer’s Disease Biomarkers in the Elderly with Different Cognitive Status. Journal of Alzheimer’s Disease Reports.
Summary by Faith Oluwamakinde
