The aim of this study was to determine the determinants of CAP among adult patients in Debre
Berhan University Hospital by including a number of variables from various categories such as socio-demographic characteristics, health status, behavioral and lifestyle factors along with oral hygiene parameters. According to the findings of this study, a recent history of a common cold, a recent history of toothache, and not cleaning teeth on a regular basis were all determined to be risk factors for community-acquired pneumonia.
The results of the current study indicate that individuals who had a recent common cold within the past two weeks had a four-fold higher likelihood of developing CAP compared to those who did not have a history of common cold. These findings are in line with a study conducted in Spain (10), Kenya (5), and Ethiopia (7, 11): that showed an increased risk of CAP due to the recent common cold. Another study from the United Kingdom showed that rhinovirus infection which is the most common etiology of common cold has been followed by a number of other microbiologic pneumonia (13). The pathogenesis of super-infection has been attributed to direct mucosal/epithelial damage by virus, increased bacterial colonization of the upper and lower respiratory tracts, which all lead to increased susceptibility to secondary bacterial infections. In addition, antiviral immune responses induced by acute respiratory infections are associated with changes in microbial composition and function in the respiratory, which in turn may alter subsequent immune function against secondary bacterial infection or alter the dynamics of intermicrobial interactions, thereby enhancing the proliferation of potentially pathogenic bacterial species (14).
In this study, individuals who did not regularly brush their teeth were 2.8 times more likely to develop CAP than those who regularly brush their teeth on a daily basis. Many research in geriatric, nursing home, hospitalized, and intensive care unit patients (15–19) have reported an association between oral health and pneumonia. Again, a Japanese study (20) revealed infrequent denture cleaning was significantly associated with pneumonia incidence. In consistent with this finding, a study from Korea (21) showed that frequent tooth brushing significantly decreased CAP. Another study from Spain (17) and Japan (10, 20) also revealed that having poor dental hygiene increase a risk to develop CAP. This finding is also consistent with a study conducted in Tigray, Ethiopia (7, 11). This association could indicate oral cavity as a reservoir of various respiratory pathogens, and poor oral hygiene is associated with an increase overgrowth of bacteria in the mouth, it's possible to inhale the microbes into lungs and it positively relates higher risk of developing pneumonia. Prevention of the accumulation of plaque and bacterial colonization, particularly in subjects with dental caries, and periodontal disease, is an important practical consequence.
This study also found that study participants who had a recent toothache were approximately 2.5
times more likely to have CAP than those without a toothache. Toothache can be caused by caries or periodontal disease, which can spread bacteria from an infected tooth or gum, most commonly by aspiration of oropharyngeal secretions, and be the cause of CAP. This finding is consistent with a study conducted in Korea (22). The connection of periodontal diseases and pneumonia might result from the colonization of pathogenic bacteria present in dental biofilm, followed by aspiration of the colonized pathogens, which is considered a significant risk factor for pneumonia. As strength, this study used primary data and only included cases of pneumonia that were radiologically confirmed. One of the potential limitation of this study was bacteriological confirmation was not used for diagnosis of CAP.