Pneumonia Risk Increased by Dementia-Related Daily Living Difficulties: Poor Oral Hygiene and Dysphagia as Contributing Factors

•What is the primary question addressed by this study?Association between pneumonia and dementia-related difficulties has been studied in detail.•What is the main finding of this study?Pneumonia in patients with dementia may be caused by two factors: an increase in pathogenic microorganisms in oral cavity due to poor oral hygiene, and an inability to eliminate aspiration contents due to dysphagia and loss of consciousnessPhysical restraint and mobility impairment showed a weaker, nonsignificant association with pneumonia.•What is the meaning of the finding?These dementia-related difficulties increase the risk of pneumonia development. Implementing measures such as oral care practices and dysphagia rehabilitation may reduce the likelihood of pneumonia development in these individuals.Further investigation is needed to clarify the relationship between physical restraint, mobility impairment, and pneumonia in this population. Although pneumonia is the leading cause of death among patients with dementia, the specific underlying causes remain unclear. In particular, the potential connection between pneumonia risk and dementia-related daily living difficulties, such as oral hygiene practice and mobility impairment, and the use of physical restraint as a management practice, has not been extensively studied. In our retrospective study, we included 454 admissions corresponding to 336 individual patients with dementia who were admitted to a neuropsychiatric unit due to behavioral and psychological symptoms. The admissions were divided into two groups: those who developed pneumonia while hospitalized (n=62) and those who did not (n=392). We investigated differences between the two groups in terms of dementia etiology, dementia severity, physical conditions, medical complications, medication, dementia-related difficulties in daily living, and physical restraint. To control potential confounding variables, we used mixed effects logistic regression analysis to identify risk factors for pneumonia in this cohort. Our study found that the development of pneumonia in patients with dementia was associated with poor oral hygiene, dysphagia, and loss of consciousness. Physical restraint and mobility impairment showed a weaker, nonsignificant association with the development of pneumonia. Our findings suggest that pneumonia in this population may be caused by two primary factors: increased pathogenic microorganisms in the oral cavity due to poor hygiene, and an inability to cl