Brain Metabolism in Women With Alzheimer Disease Linked to Verbal Memory

LOS ANGELES — Women with Alzheimer disease (AD) have higher levels of brain metabolism compared with men, which may contribute to their superior verbal memory performance at various disease stages, according to study results presented at the Alzheimer’s Association International Conference 2019 held July 14-18 in Los Angeles, California.

The study included patients from the Alzheimer’s Disease Neuroimaging Initiative. At baseline, patients completed the Rey Auditory Verbal Learning Test and assessments of regional glucose metabolism (measured by [18F]Fluorodeoxyglucose positron emission tomography), cortical amyloid-β burden, and/or cerebrospinal fluid (CSF) phosphorylated-tau (p-tau) levels.

Researchers divided the patients into quartiles of amyloid-β burden and CSF p-tau levels (higher quartile equals greater pathology). Within quartiles, sex differences in glucose metabolism were tested; regions of interest included posterior cingulate, angular gyrus, and inferior/middle temporal gyrus. Investigators conducted stepwise linear regressions to examine associations between sex and Delayed Recall scores after adjusting for age, education, APOE4, and glucose metabolism.

Of 1022 patients, 453 were women and 569 were men. Results indicated that women had a significantly higher glucose metabolism compared with men at Quartiles 1 to 2 of amyloid-β burden (PS=.001) and at Quartiles 1 and 3 of CSF p-tau (PS <.01).

At Quartiles 1 to 3 of amyloid-β burden, women outperformed men on Delayed Recall. However, the same was not true in Quartile 4. After adjusting for metabolism, the sex difference in Delayed Recall was minimally attenuated in Quartiles 1 to 2 of both pathologic markers (3-9%), moderately attenuated in Quartile 3 of both markers (37-41%), and moderately attenuated in Quartile 4 of CSF p-tau (21%).

“Women may be better able than men to maintain brain metabolic function at moderate levels of AD pathology, and this ability may support the persistence of the female verbal memory advantage at this AD stage,” the researchers wrote.

Reference

Sundermann E. Higher brain glucose metabolism in women supports the persistence of the female advantage in verbal memory at moderate levels of AD pathology. Abstract presented at: The Alzheimer’s Association International Conference 2019; July 14-18, 2019; Los Angeles, California.