title: Nationwide epidemiological survey of chronic hypersensitivity pneumonitis in Japan.
abstract: BACKGROUND
  In 1999, a Japanese epidemiological survey of chronic hypersensitivity pneumonitis (HP) showed that summer-type HP was the most prevalent variant of the disease. The number of reported cases of chronic HP has recently been increasing, and the clinical features of the disease seem to have changed. We conducted another nationwide epidemiological survey of chronic HP in Japan to determine better estimates of the frequency and clinical features of the disease.
  
  
  METHODS
  A questionnaire was sent to qualified hospitals throughout Japan, and data on cases of chronic HP diagnosed between 2000 and 2009 were collected.
  
  
  RESULTS
  In total, 222 cases of chronic HP from 22 hospitals were studied. Disease subtypes included bird-related HP (n=134), summer-type HP (n=33), home-related HP (n=25), farmer's lung (n=4), isocyanate-induced HP (n=3), and other types (n=23). The median proportion of lymphocytes in bronchoalveolar lavage fluid was high (24.5%). The primary findings of computed tomography of the chest were ground-glass attenuation and interlobular septal thickening. Centrilobular fibrosis was the major pathological finding on examination of surgical lung biopsy specimens from 93 patients. The median survival time was 83 months.
  
  
  CONCLUSIONS
  The proportion of bird-related HP was higher than that in the previous epidemiological survey, and the proportions of isocyanate-induced HP and farmer's lung were lower. A crucial step in diagnosing chronic HP is to thoroughly explore the possibility of antigen exposure.
authors: Department of Integrated Pulmonology, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. tokamoto.pulm@tmd.ac.jp
authors: Tsukasa
authors: T
authors: Okamoto
authors: Yasunari
authors: Y
authors: Miyazaki
authors: Takashi
authors: T
authors: Ogura
authors: Kingo
authors: K
authors: Chida
authors: Nobuoki
authors: N
authors: Kohno
authors: Shigeru
authors: S
authors: Kohno
authors: Hiroyuki
authors: H
authors: Taniguchi
authors: Shinobu
authors: S
authors: Akagawa
authors: Yoshiro
authors: Y
authors: Mochizuki
authors: Kohei
authors: K
authors: Yamauchi
authors: Hiroki
authors: H
authors: Takahashi
authors: Takeshi
authors: T
authors: Johkoh
authors: Sakae
authors: S
authors: Homma
authors: Kazuma
authors: K
authors: Kishi
authors: Soichiro
authors: S
authors: Ikushima
authors: Satoshi
authors: S
authors: Konno
authors: Michiaki
authors: M
authors: Mishima
authors: Ken
authors: K
authors: Ohta
authors: Yasuhiko
authors: Y
authors: Nishioka
authors: Nobuyuki
authors: N
authors: Yoshimura
authors: Mitsuru
authors: M
authors: Munakata
authors: Kentaro
authors: K
authors: Watanabe
authors: Yoshihiro
authors: Y
authors: Miyashita
authors: Naohiko
authors: N
authors: Inase
mesh_terms: D000368:Aged; D000542:Alveolitis, Extrinsic Allergic / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000276:immunology / Q000473:pathology; D000941:Antigens / Q000276:immunology; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D002908:Chronic Disease; D005260:Female; D005355:Fibrosis; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D011795:Surveys and Questionnaires; D014057:Tomography, X-Ray Computed
chemical_list: D000941:Antigens
keywords: Extrinsic allergic alveolitis; Hypersensitivity pneumonitis; Pulmonary fibrosis; Surveillance