Presence of Alzheimer's Biomarkers, Low BMI Linked

Strongest association seen in individuals with mild cognitive impairment and no dementia

MONDAY, Nov. 21 (HealthDay News) -- Biomarkers of increased Alzheimer's disease (AD) burden, including Pittsburgh Compound B (PiB), β-amyloid peptide (Aβ), and total tau, are associated with lower body mass index (BMI) in individuals with mild cognitive impairment (MCI) or no dementia, according to a study published in the Nov. 22 issue of Neurology.

Eric D. Vidoni, P.T., Ph.D., from the University of Kansas Medical Center in Missouri, and colleagues examined the association of BMI with potential underlying biological substrates for cognitive impairment in participants of the Alzheimer's Disease Neuroimaging Initiative (ADNI). Data were analyzed from 101 participants who underwent positron emission tomography imaging using PiB, and from 405 participants with cerebrospinal fluid (CSF) analyses for Aβ and total tau. The association of CSF biomarkers and global PiB uptake with BMI was measured, controlling for age and gender. BMI differences were assessed between individuals who were and were not considered to be biomarker positive. BMI change over two years was assessed in relation to AD biomarkers.

The investigators found that age, education, or BMI status did not differ amongst the no dementia, MCI, and AD groups. In the overall sample, there was a significant association of CSF Aβ, tau, tau/Aβ ratio, and global PiB uptake with BMI. These biomarkers of increased AD burden correlated with lower BMI, and levels indicative of pathophysiology were found in fewer overweight individuals. These associations were strongest in the MCI and no dementia groups.

"The presence and burden of in vivo biomarkers of cerebral amyloid and tau are associated with lower BMI in cognitively normal and MCI individuals," the authors write.

One of the study authors disclosed financial ties to the pharmaceutical industry. ADNI was funded by the pharmaceutical industry.

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