Alzheimer's disease and peripheral infections: the possible contribution from periodontal infections, model and hypothesis

J Alzheimers Dis. 2008 May;13(4):437-49. doi: 10.3233/jad-2008-13408.


Alzheimer's disease (AD) affects approximately 4.5 million people in the U.S. and this number will increase as the population ages and the life-span increases. Therefore, of paramount importance is identifying mechanisms and factors that affect the risk of developing AD. The etiology and pathogenic mechanisms for AD have not been defined, although inflammation within the brain is thought to play a role. Consistent with this hypothesis, studies suggest that peripheral infections contribute to the inflammatory state of the central nervous system. Periodontitis is a prevalent, persistent peripheral infection associated with gram negative, anaerobic bacteria that are capable of exhibiting localized and systemic infections in the host. This review offers a hypothetical link between periodontitis and AD and will present possible mechanistic links between periodontitis related inflammation and AD. It will review the pathogenesis of periodontitis and the mechanisms by which periodontal infections may affect the onset and progression of AD. Since periodontitis is a treatable condition, it may be a readily modifiable risk factor for AD.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Alzheimer Disease / epidemiology*
  • Alzheimer Disease / physiopathology*
  • Bacterial Infections / complications*
  • Bacterial Infections / epidemiology*
  • Humans
  • Nerve Degeneration / epidemiology
  • Nerve Degeneration / microbiology
  • Nerve Degeneration / physiopathology
  • Periodontal Diseases / epidemiology*
  • Periodontal Diseases / microbiology*