PET scans indicate women may have higher Alzheimer’s risk than men

New PET-based research revealed biological insight into why women may be more prone to developing Alzheimer’s compared to men.

A team from Vanderbilt University Medical Center presented evidence at the Alzheimer’s Association International Conference (AAIC) in Los Angeles on Tuesday that suggests tau may travel differently in the brains of women than in men.

“The majority of people living with Alzheimer’s are women and it’s imperative we understand why,” said Maria C. Carrillo, PhD, Alzheimer’s Association chief science officer, in a statement. “The research reported today at AAIC gets us one step closer to answering that question by identifying specific biological and social reasons why Alzheimer’s is different in men and women.”

While plenty of studies have focused on amyloid as a signal of future Alzheimer’s development, abnormal buildup of the tau protein also plays a central role in identifying those at high-risk of the disease. It may also be true that the brain connectivity differences between men and women play a role in how tau spreads through the brain.

In the study presented at AAIC, Sepideh Shokouhi, PhD, assistant professor of psychiatry and behavioral sciences at Vanderbilt, and colleagues analyzed PET scans of 101 men and 60 women with mild cognitive impairment (MCI) and 123 healthy men and 178 healthy women.

In each group, tau networks were created to reflect three things: the total number of connections, areas within the brain with the highest tau connectivity and regions that played a role in the spread of tau across the brain.

Using the scans, the team examined the architecture of tau-connected regions of the brain, searching for “global pathways” of tau propagation in men and women.

Shokouhi et al. found the tau networks in women with MCI stood out from the other three groups in that they had the highest density of tau protein and increased brain-wide tau burden. Women with MCI had a density of 0.38 ± 0.03 compared to that of men with MCI (0.21 ± 0.02) healthy men (0.11 ± 0.02) and healthy women. (0.12 ± 0. 02).

The team also found that the parahippocampus, superior parietal, insular and superior temporal brain regions in healthy women connected different brain areas within the network, a finding that may indicate tau protein spread throughout the brains of women faster and ultimately lead to a quicker cognitive decline. 

“The differences that we observed indicate the strong possibility that there are sex differences in the structural and functional connections in the brain, which may contribute to women’s increased risk for Alzheimer’s,” Shokouhi said in the same statement. “This study has implications for the possibility of creating sex-specific risk-reduction strategies and preventive interventions.”