title: COPD in Japan: the Nippon COPD Epidemiology study.
abstract: OBJECTIVE
  Despite high smoking rates, few prevalence studies of COPD have been performed in Asia. The Nippon COPD Epidemiology (NICE) Study used spirometry to measure prevalence of airflow limitation in Japanese adults.
  
  
  METHODS
  Clinical, spirometric, and risk factor exposure data were collected on 2343 subjects aged > or = 40 years who were demographically similar to the Japanese population. Airflow limitation was defined according to Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria (FEV1/FVC < 70%).
  
  
  RESULTS
  Prevalence of airflow limitation was 10.9%. Based upon GOLD severity criteria, 56% of these cases were found to be mild, 38% moderate, 5% severe, and 1% very severe. Airflow limitation was significantly more prevalent in males than females (16.4% vs. 5.0%; P < 0.001), in male ever-smokers than female ever-smokers (17.1% vs. 7.5%; P < 0.001), and in older subjects (3.5% in 40-49 years olds vs. 24.4% in those > 70 years; P < 0.001). Of note, airflow limitation was also found in 5.8% of non-smokers and 4.6% of those younger than age 60 years. Only 9.4% of cases with airflow limitation reported a previous diagnosis of COPD.
  
  
  CONCLUSIONS
  Prevalence of airflow limitation in Japan is higher than previously reported, suggesting a high degree of under-recognition of COPD. The high prevalence of smoking coupled with an aging population threatens to further increase the burden of COPD, highlighting the need for enhanced screening efforts and interventions of prevention and treatment.
authors.affiliation: Department of Respiratory Medicine, Juntendo University, Tokyo, Japan. yfukuchi@med.juntendo.ac.jp
authors.forename: Yoshinosuke
authors.initials: Y
authors.lastname: Fukuchi
authors.forename: Masaharu
authors.initials: M
authors.lastname: Nishimura
authors.forename: Masakazu
authors.initials: M
authors.lastname: Ichinose
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Adachi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nagai
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kuriyama
authors.forename: Keiji
authors.initials: K
authors.lastname: Takahashi
authors.forename: Koichi
authors.initials: K
authors.lastname: Nishimura
authors.forename: Shinichi
authors.initials: S
authors.lastname: Ishioka
authors.forename: Hisamichi
authors.initials: H
authors.lastname: Aizawa
authors.forename: Carol
authors.initials: C
authors.lastname: Zaher
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D015897:Comorbidity; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology*; D012044:Regression Analysis; D017678:Sex Distribution; D012907:Smoking / Q000453:epidemiology