@article{oai:nagasaki-u.repo.nii.ac.jp:00004215,
 author = {Morimoto, Konosuke and Suzuki, Motoi and Ishifuji, Tomoko and Yaegashi, Makito and Asoh, Norichika and Hamashige, Naohisa and Abe, Masahiko and Aoshima, Masahiro and Ariyoshi, Koya},
 issue = {3},
 journal = {PLOS ONE},
 month = {Mar},
 note = {Background: The increasing burden of pneumonia in adults is an emerging health issue in the era of global population aging. This study was conducted to elucidate the burden of community-onset pneumonia (COP) and its etiologic fractions in Japan, the world's most aged society. Methods: A multicenter prospective surveillance for COP was conducted from September 2011 to January 2013 in Japan. All pneumonia patients aged ?15 years, including those with community-acquired pneumonia (CAP) and health care-associated pneumonia (HCAP), were enrolled at four community hospitals on four major islands. The COP burden was estimated based on the surveillance data and national statistics. Results: A total of 1,772 COP episodes out of 932,080 hospital visits were enrolled during the surveillance. The estimated overall incidence rates of adult COP, hospitalization, and in-hospital death were 16.9 (95% confidence interval, 13.6 to 20.9), 5.3 (4.5 to 6.2), and 0.7 (0.6 to 0.8) per 1,000 person-years (PY), respectively. The incidence rates sharply increased with age; the incidence in people aged ?85 years was 10-fold higher than that in people aged 15-64 years. The estimated annual number of adult COP cases in the entire Japanese population was 1,880,000, and 69.4% were aged ?65 years. Aspiration-associated pneumonia (630,000) was the leading etiologic category, followed by Streptococcus pneumoniae-associated pneumonia (530,000), Haemophilus influenzae-associated pneumonia (420,000), and respiratory virus-associated pneumonia (420,000), including influenza-associated pneumonia (30,000)., PLoS ONE, 10(3), e0122247; 2015},
 title = {The Burden and Etiology of Community-Onset Pneumonia in the Aging Japanese Population: A Multicenter Prospective Study},
 volume = {10},
 year = {2015}
}