Infection burden, periodontal pathogens, and their interactive association with incident all-cause and Alzheimer's disease dementia in a large national survey

INTRODUCTION: Relationships and interplay of an infection burden (IB) and periodontal pathogens or periodontal disease (Pd) markers with Alzheimer's disease (AD) and all-cause dementia among US adults were examined. METHODS: Less than or equal to 2997 participants from the National Health and Nutrition Survey III were linked to CMS-Medicare [>= 45 years (1988-1994); <= 30 years follow-up]. RESULTS: Hepatitis C (hazard ratio = 3.33, p = 0.004) and herpes simplex virus 2 were strongly associated with greater all-cause dementia risk. Porphyromonas gingivalis and Streptococcus oralis were associated with greater AD risk at higher IB. The red-green periodontal pathogen cluster coupled with higher IB count increased the risk of all-cause dementia among minority racial groups. Pocket probing depth associated with dementia risk at lower IB in the overall sample. DISCUSSION: Select viruses and bacteria were associated with all-cause and AD dementia, while the IB interacted with Pd markers in relation to these outcomes.