Oral Self-Care, Pneumococcal Vaccination, and Pneumonia Among Japanese Older People, Assessed With Machine Learning.

Background: Pneumonia is a leading cause of death worldwide. It is a particularly serious burden in older people, as they tend to have a weakened immune response. Identifying the role of oral self-care and pneumococcal vaccination in healthy, independent older people can aid pneumonia prevention among them. This study investigated the associations between oral self-care, pneumococcal vaccination, and pneumonia experience among independent older people.

Methods: This cross-sectional study used data from the 2016 Japan Gerontological Evaluation Study. We used machine learning to examine the association between oral self-care and the experience of pneumonia over the previous year, stratified by pneumococcal vaccination. The covariates were sex, age, years of education, equivalent annual income, medical history of stroke, oral health status (choking, dryness, number of teeth), and smoking status. The analysis included 17 217 independent older people aged 65 and over.

Results: The prevalence of pneumonia experienced among those who brushed their teeth once or less per day was 4.5% and 5.3% for those with and those without pneumococcal vaccinations, respectively. In the unvaccinated group, the odds ratio of pneumonia experience for those who brushed their teeth once or less a day was 1.57 (95% confidence interval: 1.15-2.14) compared to those who brushed their teeth 3 or more times a day. By contrast, there was no significant association between the frequency of toothbrushing and the experience of pneumonia among people who received pneumococcal vaccination.

Conclusions: Oral care influenced the experience of pneumonia among independent older people who did not receive pneumococcal vaccination.