Periodontitis and respiratory diseases: discussion, conclusions, and recommendations.

Abstract

DOES AN ASSOCIATION BETWEEN PERIODONTITIS AND RESPIRATORY DISEASE EXIST? Several factors must be taken into account in considering whether an association between previously existing periodontitis and risk for respiratory disease exists. Among these are the strength of the claimed association, consistency among the studies, temporality, dose effect, biologic plausibility, and experimental evidence. Dr. Garcia has pointed out clearly that there is a paucity of published data.2 His systematic structured review of the relevant literature revealed only 2 major studies. Scannapieco and coworkers4,5 analyzed the cross-sectional NHANES I and NHANES III national data sets, and Hayes and coworkers6 analyzed the data from the longitudinal VA Normative Aging Study. Using well-controlled multivariate analyses, both studies reported odds ratios ranging from 1.8 to 4.5 (95% confidence level) for the association between periodontitis and chronic obstructive pulmonary disease. Notably, the odds ratios reported are in the same range as those reported for the association between periodontitis and other systemic diseases such as cardiovascular disease and stroke. While the studies are consistent with one another, the number of studies is too few to reach definitive conclusions. The demonstration that periodontitis existed before the onset of respiratory disease, usually referred to as temporality, is essential for establishing an association, especially causality. Since the Scannapieco studies4,5 were cross-sectional in design, they could not demonstrate temporality. Temporality was demonstrated in the Hayes et al. study.6 None of the studies demonstrated a dose effect (i.e., that the risk for respiratory disease increases with increasing severity and duration of periodontitis). However, in light of the complexity and multifactorial nature of respiratory disease (see below), demonstration of a dose effect for the association between periodontitis and respiratory disease is likely to be impossible. I would like to compliment the speakers on the respiratory diseases session of the program for their lucid and thorough coverage of their assigned topics. Dr. Terpenning1 has provided an excellent explanation of normal pulmonary function and defense, and described several diseases and other factors that enhance the likelihood of infection of the lungs by oral and other bacteria and viruses. Dr. Garcia2 has given us an incisive summary of the epidemiological data related to the possible association between previously existing periodontitis and risk for respiratory disease based on a systematic structured review of the relevant literature. Dr. Scannapieco3 has not only summarized existing literature concerning potential mechanisms through which periodontitis can enhance risk for respiratory disease but also presented the results of his own studies aimed at demonstrating the validity of some of these mechanisms. All 3 of the speakers have pointed out the pressing need for additional research.