1. United Nations. World population prospects 2022. (2022). https.//population.un.org/wpp/.
2. Cabinet Office. White paper on population aging. (2023). https.//www8.cao.go.jp/kourei/english/annualreport/index-wh.html.
3. Ministry of Health, Labour and Welfare of Japan. Summary of vital statistics. (2022). https.//www.mhlw.go.jp/english/database/db-hw/populate/index.html.
4. Aspiration pneumonia;Mandell LA;N Engl J Med,2019
5. Aspiration pneumonia;Niederman MS;Rev Esp Quimioter,2022