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Science in the News

A Recent Review Article Posits that Tooth Loss May Predict Shortened Longevity

February 03, 2017 A recent review article by Friedman and Lamster1 in the journal Periodontology 2000 has been picked up by the news media because the paper’s discussion section concludes that tooth loss affects longevity and life expectancy.

In the article, the authors briefly describe their literature search strategy of 4 databases and state that the search identified “over 650 articles,” of which 129 were selected for further examination.  Although the authors indicate that the text of their paper reflected the information found in these 129 articles, the paper’s formal reference list includes a total of only 65 citations. An omission of this sort is one of the differentiators between this type of review article and a systematic review or rapid review.2  Without further insight about how papers were selected for inclusion in the study, it leaves open the possibility of selection bias.

The first sentence of the paper states that the objective of the review is to “examine a number of variables that contribute to tooth loss” and “proposes a hypothesis for future investigation.” While the article highlights the “special modifying risk factors” of osteoporosis and cognitive impairment, tooth loss is actually a complex outcome affected not only by a person’s dental disease, but by their lifetime access to dental care, likelihood of oral trauma, and both skill and commitment to oral hygiene.3  When examining associations between disease processes and a downstream consequence such as life expectancy, it is valuable to consider the nature of the relationship.  Does one drive the other or are there factors that might influence development of both?  Although the authors focus on tooth loss as a predictor, it is well known that advancing age also tracks with increasing risk of cardiovascular, neoplastic, neurodegenerative, and metabolic diseases,4 including periodontal disease.5

The paper by Friedman and Lamster does not include any modeling or meta-analysis of data derived from the studies they cite.  Thus, while the paper proposes an interesting hypothesis and may have potential to stimulate fruitful research, it cannot be used to draw conclusions about the strength or nature of the theorized association between tooth loss and longevity.


  1. Friedman PK, Lamster IB. Tooth loss as a predictor of shortened longevity: exploring the hypothesis. Periodontol 2000 2016;72(1):142-52.
  2. Grant MJ, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health Info Libr J 2009;26(2):91-108.
  3. Kassebaum NJ, Bernabe E, Dahiya M, et al. Global Burden of Severe Tooth Loss: A Systematic Review and Meta-analysis. J Dent Res 2014;93(7 Suppl):20S-28S.
  4. Armanios M, de Cabo R, Mannick J, et al. Translational strategies in aging and age-related disease. Nat Med 2015;21(12):1395-9.
  5. Eke PI, Dye BA, Wei L, et al. Prevalence of periodontitis in adults in the United States: 2009 and 2010. J Dent Res 2012;91(10):914-20.

About Science in the News

Science in the News is a service by the American Dental Association (ADA) to its members to present current information about science topics in the news. The ADA is a professional association of dentists committed to the public's oral health, ethics, science and professional advancement; leading a unified profession through initiatives in advocacy, education, research and the development of standards. As a science-based organization, the ADA's evaluation of the scientific evidence may change as more information becomes available. Your thoughts would be greatly appreciated.

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