Public Health.

Area of Science:

• Neuroscience
• Infectious Disease Epidemiology
• Gerontology

Background:

• Emerging literature suggests a connection between past viral and microbial infections and the risk of developing Alzheimer's disease and other neurodegenerative conditions.
• Recent studies indicate that viral infections may play a role in cognitive performance.

Purpose of the Study:

• To investigate the association between infectious burden and cognitive status in the Wisconsin Registry for Alzheimer's Prevention (WRAP) cohort.
• To explore the relationship between infection history and cognitive test performance.

Main Methods:

• Medical history spreadsheets from the WRAP cohort (over 1500 participants) were analyzed for a history of viral, bacterial, and autoimmune infections.
• Statistical analyses, including Wilcoxon rank-sum, Chi-square, and regression, compared diagnosis status (dementia, mild cognitive impairment, unimpaired-declining) and cognitive test results across infection counts (0, 1, 2+).
• Analyses controlled for age, sex, APOE status, education, race, and visit/test numbers.

Main Results:

• A significant increase in the proportion of participants with a positive diagnosis (dementia, MCI, or subclinical impairment) was observed with higher infection counts (21.2% for 0 infections, 27.6% for 1, and 31.7% for 2+; p=0.02).
• Participants with at least two infections showed significantly longer completion times for the Trails B test (72 seconds) compared to those with no infections (59 seconds).
• Regression analyses confirmed the significance of these associations after adjusting for multiple covariates.

Conclusions:

• The number of reported infections is significantly associated with cognitive status in the WRAP cohort.
• Infectious burden is linked to cognitive performance, specifically on the Trails B test.