Risk of Dementia and Structural Brain Changes Following Nonneurological Infections During 9-Year Follow-Up

Objectives: Given the strong association between systemic inflammation and cognitive decline, we aimed to determine whether nonneurologic infections are associated with accelerated cognitive decline and structural changes in the brain using pre- and post-infection neuropsychologic assessments and repeated brain MR images.

Design: Additional analysis of the prospective observational Radboud University Nijmegen Diffusion Tensor and Magnetic Resonance Cohort study.

Setting: Single-center study at the Radboud university medical center, Nijmegen, The Netherlands, between January 2006 and September 2015.

Patients: Five-hundred three participants (50-85 yr old) with cerebral small vessel disease were included and followed for 9 years.

Measurements and main results: Participants underwent repeated cognitive measurements and brain MRI. Infectious events were collected. Sepsis episodes were analyzed, and additionally, patients were stratified in three groups: having had a severe infectious episode (e.g., sepsis or hospitalization for infection), a mild, or no infectious episode. Development of dementia, trajectories of cognition, and structural brain changes on MRI in the subsequent follow-up periods were compared between the groups. Complete infectious data were available from 331 patients (mean age 64 ± 8 yr, 57% males). Twenty-nine participants (9%) suffered from a sepsis episode, 69 (21%) from a severe, 201 (61%) from a mild, and 61 (18%) had no infectious episode during follow-up. After correction for age, baseline cognition, and brain volume, each sepsis episode remained associated with an 82% increased risk to develop dementia within the follow-up period (hazard ratio, 1.82; 95% CI, 1.07-3.10; p = 0.027). Infections had no effect on the trajectory of structural changes to the brain after correction for baseline differences.

Conclusions: In this 9-year observational follow-up study, sepsis episodes were associated with subsequent development of dementia. Nonneurologic infections had no effect on the trajectory of structural cerebral changes.