WHICAP Ancillary Study of Oral Health: MRI and Neuropsychological Findings

Objectives: Periodontitis has been associated with cognitive decline and Alzheimer’s disease in epidemiological studies and translational models. The WHICAP Ancillary Study of Oral Health is a multiethnic longitudinal study of 1,130 individuals in Northern Manhattan, aged 65y+ years. We explored associations of periodontitis with contemporaneous neuroimaging features and with longitudinal neuropsychological test performance over a mean follow-up of 3.6±1.2 years.
Methods: Of 1,130 participants enrolled, 907 received full-mouth periodontal examinations, 1,054 had assessments of serum IgG antibodies to periodontal bacteria, and 778 had subgingival plaque analyzed by means of HOMINGS. Contemporaneous MRI assessments were available as follows: presence/absence of white matter T2 hyperintensities (WMH) and cerebral microbleeds (CMB) from 594 participants; and cortical thickness in regions typically affected by Alzheimer’s disease (‘AD signature’), entorhinal cortical (ERC) thickness, and hippocampal volume (HV) from 612 participants. A number of neuropsychological assessments were available longitudinally from up to 878 participants.
Results: In cross-sectional analyses, and in models adjusted for demographics, education, heart disease, diabetes, hypertension, smoking and apoE genotype, tooth loss and the % of teeth with CAL≥3mm were associated with WMH, ‘AD signature’ and ERC thickness; % of teeth with CAL≥3mm, antibody levels to Fusobacterium nucleatum, and periodontal microbial alpha-diversity (Shannon index) were associated with CMB; and antibody levels to Prevotella intermedia with HV. In longitudinal analyses, moderate/severe periodontitis (according to the CDC/AAP classification) and % of teeth with PD≥4mm at baseline were associated with incident cognitive decline in fully adjusted models. In analyses of continuous repeated outcomes, higher number of teeth present and microbial alpha-diversity at baseline were associated with attenuated memory loss, after adjustments as described above.
Conclusions: IIn this multiethnic cohort, measures of periodontitis were associated with neuroimaging evidence of Alzheimer’s disease and incident cognitive decline. Further exploration of mechanistic links is warranted.