title: Non-linear association of periodontal pathogen antibodies with mortality.
abstract: BACKGROUND
  Periodontal pathogens are associated with predisposition to chronic diseases and death. Antibody levels against them reflect flora burden, although high levels might indicate a protective response. We studied all-cause and cause specific mortality in relation to antibody levels in a representative US sample.
  
  
  METHODS
  Adults ≥ 20 years (n=6993) from the second phase of the Third National Health and Nutrition Examination Survey (NHANES III) were followed for a median of 13.2 years. Serum antibodies against Porphyromonas gingivalis (antiPG) and Actinobacillus actinomycetemcomitans (antiAA) were quantified by ELISA at baseline (1991-1994). Mortality hazard ratios (HRs) were calculated across antibody quartiles using the quartile with highest mortality as reference.
  
  
  RESULTS
  Median (25th, 75th percentiles) antiPG was 72 (63, 93) ELISA Units (EU) and median antiAA was 70 (64, 89) EU. After adjustment for potential confounders, mortality was highest for participants with antibodies in the third antiPG quartile (72-92 EU), with lower mortality risk for values not only below but also above this range [HR for the 1st to 4th quartiles: 0.81 (95% CI: 0.65, 1.01), 0.67 (95% CI: 0.55, 0.82), 1.00 (Reference), 0.79 (95% CI: 0.64, 0.97)]. In spline regression models the association had an inverted U-shape and mortality exhibited a peak at 84 EU (67th percentile). Mortality was not associated with antiAA.
  
  
  CONCLUSIONS
  Mortality was highest for those just above the median antiPG and a reduced risk was present among those with low or high levels of the antibody. Future studies should confirm this downward trend in upper levels and investigate a potential protective role of immunity against P. gingivalis.
authors: Department of Epidemiology, Atherothrombosis and Imaging, Spanish National Center for Cardiovascular Research (CNIC), Madrid, Spain.
authors: Damian
authors: D
authors: Sanchez-Torres
authors: Department of Epidemiology, Atherothrombosis and Imaging, Spanish National Center for Cardiovascular Research (CNIC), Madrid, Spain.
authors: Dayro
authors: D
authors: Gutierrez-Bejarano
authors: Department of Epidemiology, Atherothrombosis and Imaging, Spanish National Center for Cardiovascular Research (CNIC), Madrid, Spain.
authors: Yamilee
authors: Y
authors: Hurtado-Roca
authors: Department of Preventive Medicine and Public Health, Universidad Autonoma de Madrid, Madrid, Spain.
authors: Pilar
authors: P
authors: Guallar-Castillon
authors: Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL, United States.
authors: Paul
authors: P
authors: Muntner
authors: Department of Epidemiology, Atherothrombosis and Imaging, Spanish National Center for Cardiovascular Research (CNIC), Madrid, Spain; Department of Preventive Medicine and Public Health, Universidad Autonoma de Madrid, Madrid, Spain; Department of Epidemiology, St. Louis University, St Louis, MO, United States. Electronic address: mlaclaustra@cnic.es.
authors: Martin
authors: M
authors: Laclaustra
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016976:Aggregatibacter actinomycetemcomitans / Q000276:immunology* / Q000302:isolation & purification; D000907:Antibodies, Bacterial / Q000097:blood*; D002318:Cardiovascular Diseases / Q000401:mortality; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017711:Nonlinear Dynamics; D010518:Periodontitis / Q000382:microbiology* / Q000401:mortality / Q000473:pathology; D016966:Porphyromonas gingivalis / Q000276:immunology* / Q000302:isolation & purification; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial
keywords: Antibodies; Mortality; NHANES III; Periodontal pathogens; Periodontitis; Third National Health and Nutrition Examination Survey