Pneumonia and Chronic Obstructive Pulmonary Disease (COPD)

      Basis of Current Understanding: Cross Sectional and Longitudinal Studies,
                                                 Case Studies

      Strength of Statistical Evidence: Pneumonia: Moderate

                                                   COPD: Weak

 Studies Link Reduction of Oral Bacteria to Reduction of Disease: Yes

      Reported Risk: Pneumonia - 740%;

                          COPD - 45-350%

            Under normal conditions, the respiratory system is equipped to eliminated bacteria normally found in the mouth and pharynx.  Pulmonary infection begins when the lining of the lower respiratory tract becomes infected. Major factors that can suppress the body’s natural ability to protect the lower respiratory tract include illness, air pollution and smoking. Recently, investigators have begun to examine whether the types and quantity of bacteria in the mouth and pharynx contribute to the risk of developing respiratory infection.   Several studies have shown that plaque and bacterial levels in the mouth increase the risk of developing respiratory diseases.  Other studies have shown that bone loss, as an indicator of Periodontal Disease, is an independent risk factor for pneumonia and COPD.   Case studies have identified bacteria that cause gum disease, such as P. gingivalis, in the lung tissues of patients with respiratory infections.

      Our current understanding of the relationship is that Periodontal Disease does not cause pneumonia, chronic bronchitis or emphysema directly.  Instead, oral bacteria are opportunistic, taking advantage of reduced immunity to invade the lower respiratory tract.  Higher levels of bacteria increase the risk of developing these conditions, especially in hospital and nursing home environments, where residents tend to be of more compromised health.

      To date, there are no studies that have investigated whether treating Periodontal Disease can reduce the risk of respiratory infection.  However, two studies have investigated the effect of  reducing total bacterial count in the mouth on the risk of respiratory infection on patients in the Intensive Care Units in hospitals.   Both studies used chlorhexadine, an antimicrobial mouth wash or gel to reduce oral bacteria, and both found a significant reduction in the risk for acquiring pneumonia when bacterial levels were reduced.