title: Serum IgG antibody levels to periodontal microbiota are associated with incident Alzheimer disease.
abstract: BACKGROUND
  Periodontitis and Alzheimer disease (AD) are associated with systemic inflammation. This research studied serum IgG to periodontal microbiota as possible predictors of incident AD.
  
  
  METHODS
  Using a case-cohort study design, 219 subjects (110 incident AD cases and 109 controls without incident cognitive impairment at last follow-up), matched on race-ethnicity, were drawn from the Washington Heights-Inwood Columbia Aging Project (WHICAP), a cohort of longitudinally followed northern Manhattan residents aged >65 years. Mean follow-up was five years (SD 2.6). In baseline sera, serum IgG levels were determined for bacteria known to be positively or negatively associated with periodontitis (Porphyromonas gingivalis, Tannerella forsythia, Actinobacillus actinomycetemcomitans Y4, Treponema denticola, Campylobacter rectus, Eubacterium nodatum, and Actinomyces naeslundii genospecies-2). In all analyses, we used antibody threshold levels shown to correlate with presence of moderate-severe periodontitis.
  
  
  RESULTS
  Mean age was 72 years (SD 6.9) for controls, and 79 years (SD 4.6) for cases (p<0.001). Non-Hispanic Whites comprised 26%, non-Hispanic Blacks 27%, and Hispanics 48% of the sample. In a model adjusting for baseline age, sex, education, diabetes mellitus, hypertension, smoking, prior history of stroke, and apolipoprotein E genotype, high anti-A. naeslundii titer (>640 ng/ml, present in 10% of subjects) was associated with increased risk of AD (HR = 2.0, 95%CI: 1.1-3.8). This association was stronger after adjusting for other significant titers (HR = 3.1, 95%CI: 1.5-6.4). In this model, high anti-E. nodatum IgG (>1755 ng/ml; 19% of subjects) was associated with lower risk of AD (HR = 0.5, 95%CI: 0.2-0.9).
  
  
  CONCLUSIONS
  Serum IgG levels to common periodontal microbiota are associated with risk for developing incident AD.
authors.affiliation: Taub Institute for Alzheimer Disease and the Aging Brain, Columbia University, New York, New York, United States of America; Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America.
authors.forename: James M
authors.initials: JM
authors.lastname: Noble
authors.affiliation: Taub Institute for Alzheimer Disease and the Aging Brain, Columbia University, New York, New York, United States of America; Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America; Department of Social Medicine, Psychiatry, and Neurology, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Scarmeas
authors.affiliation: Division of Periodontics, Section of Oral and Diagnostic Sciences, Columbia University College of Dental Medicine, New York, New York, United States of America.
authors.forename: Romanita S
authors.initials: RS
authors.lastname: Celenti
authors.affiliation: Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America; Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, United States of America.
authors.forename: Mitchell S V
authors.initials: MS
authors.lastname: Elkind
authors.affiliation: Evelyn F. McKnight Brain Institute, Departments of Neurology and Epidemiology & Public Health Sciences, and the Neuroscience Program, Leonard M. Miller School of Medicine, University of Miami, Miami, Florida, United States of America.
authors.forename: Clinton B
authors.initials: CB
authors.lastname: Wright
authors.affiliation: Taub Institute for Alzheimer Disease and the Aging Brain, Columbia University, New York, New York, United States of America.
authors.forename: Nicole
authors.initials: N
authors.lastname: Schupf
authors.affiliation: Division of Periodontics, Section of Oral and Diagnostic Sciences, Columbia University College of Dental Medicine, New York, New York, United States of America.
authors.forename: Panos N
authors.initials: PN
authors.lastname: Papapanou
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000097:blood / Q000453:epidemiology*; D000907:Antibodies, Bacterial / Q000097:blood*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D015994:Incidence; D008297:Male; D064307:Microbiota; D010518:Periodontitis / Q000097:blood / Q000453:epidemiology* / Q000382:microbiology
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G