The authors analyzed data from 982 participants in the Baltimore Longitudinal Study of Aging: they tracked the participants' brain volumes and infection histories. It turned out that six infections were associated with a greater loss of brain volume.

These diseases include influenza, herpes viruses, upper and lower respiratory tract infections, skin infections and various viral infections. Moreover, flu and herpes infections have shown a specific association with the loss of brain volume in the temporal lobe, which is crucial for memory.

"Our results confirm the role of infections in the risk of dementia and identify molecular mediators through which infections can contribute to neurodegeneration," the researchers reported.