Oral Health Impact on Respiratory Diseases

Oral health and respiratory diseases are intimately linked through multiple biological pathways and shared risk factors. Poor oral hygiene and periodontitis facilitate the aspiration of pathogenic bacteria into the lower respiratory tract, where they can colonise and trigger inflammation. Subgingival biofilms rich in anaerobic organisms such as Porphyromonas gingivalis and Prevotella species have been identified as contributors to pneumonia, chronic obstructive pulmonary disease (COPD) exacerbations, and other pulmonary complications. Inflammation originating in the periodontal tissues promotes systemic cytokine release and neutrophil activation, which can exacerbate airway inflammation and tissue remodelling in chronic lung conditions. Epidemiological evidence indicates that tooth loss and high caries burden are associated with increased pneumonia risk, while regular tooth brushing and professional dental cleaning confer protective effects. Mechanistic studies in animal models confirm that immune cell subsets, including γδ T cells and M2 macrophages, mediate interactions between oral inflammation and lung injury. The global ageing population and rising prevalence of chronic respiratory diseases underscore the importance of integrating oral health into preventive and therapeutic strategies. Interdisciplinary collaboration between dental care professionals and respiratory specialists offers practical avenues to improve outcomes and reduce healthcare burden.

Research from Nature Portfolio

A large-scale population cohort study examined oral health parameters and subsequent pneumonia risk in a general population sample. Individuals with greater numbers of dental caries and missing teeth faced a significantly higher hazard of pneumonia, while those with frequent tooth brushing and routine professional cleaning experienced a marked reduction in incidence. These findings persisted after adjustment for age, comorbidities and socioeconomic variables, suggesting a direct link between oral hygiene behaviours and respiratory infection risk. The study emphasises the potential of public health measures centred on oral health improvement to mitigate pneumonia burden across diverse populations.

Oral Health Impact on Respiratory Diseases publication trend

The graph below shows the total number of articles in oral health impact on respiratory diseases across all publications each year (not limited to Nature Index journals).

Technical terms

Periodontitis: A chronic inflammatory disease of the periodontal tissues leading to destruction of supporting tooth structures.

Oral microbiome: The community of microorganisms residing in the oral cavity, including bacteria, viruses and fungi.

Chronic obstructive pulmonary disease (COPD): A progressive lung disorder characterised by airflow obstruction and chronic inflammation.

Aspiration pneumonia: Lung infection caused by inhalation of oropharyngeal contents into the lower airways.

γδ T cells: A subset of T lymphocytes with distinct T cell receptors involved in innate and adaptive immune responses.

M2 macrophages: An alternatively activated macrophage phenotype associated with tissue repair and immunoregulation.

Mendelian randomisation: A genetic epidemiology method that uses inherited genetic variants to infer causal effects of exposures on outcomes.

References

1. Periodontitis aggravates COPD through the activation of γδ T cell and M2 macrophage. mSystems (2024).
2. Oral microbial dysbiosis in patients with periodontitis and chronic obstructive pulmonary disease. Frontiers in Cellular and Infection Microbiology (2023).
3. Association between oral microbiome and five types of respiratory infections: a two-sample Mendelian randomization study in east Asian population. Frontiers in Microbiology (2024).
4. Association between oral health and incidence of pneumonia: a population-based cohort study from Korea. Scientific Reports (2020).