title: Epidemiology and distribution of interstitial lung diseases in Turkey.
abstract: BACKGROUND
  There is very few data on the epidemiological features of interstitial lung diseases (ILD) in the literature. These studies on this subject suffer from limited number of patients.
  
  
  OBJECTIVE
  The goal of this study was to evaluate the epidemiological features of ILD in Turkey.
  
  
  METHODS
  Fifty-four investigators, 31 centres in 19 cities from six regions of Turkey, participated in the study. Two thousand two hundred forty-five newly diagnosed patients (51.8% females), led by Turkish Thoracic Society Clinical Problems Study Group, enrolled in this prospective study.
  
  
  RESULTS
  The mean age was 51.8 ± 16.7 years. The mean age among males was 50.5 ± 18.6 years and 53.0 ± 14.6 years among females (P < 0.001). 23.8% of the cases had ILD with known causes, while 39.4% were in granulomatous group, 23.7% were idiopathic, and 4.4% were in the unclassified group. Overall, histopathologically confirmed diagnosis rate was 40.4%. Sarcoidosis was the most common disease (37%), whereas cases with idiopathic pulmonary fibrosis (IPF) constituted 19,9% of patients. 53% of the sarcoidosis patients were females, and the ratio reaches to 75% under 50 years of age (for this group, IPF ratio is %3). In contrast, sarcoidosis and IPF ratios were equal in males (25%). Sarcoidosis was 8% in men over 50, while IPF was %45.
  
  
  CONCLUSIONS
  The overall incidence of ILD in Turkey was computed to be 25.8/100,000.
authors.affiliation: Department of Pulmonary Diseases, Cerrahpasa Medical Faculty, Istanbul University, İstanbul, Turkey.
authors.forename: Benan
authors.initials: B
authors.lastname: Musellim
authors.forename: Gulfer
authors.initials: G
authors.lastname: Okumus
authors.forename: Esra
authors.initials: E
authors.lastname: Uzaslan
authors.forename: Metin
authors.initials: M
authors.lastname: Akgün
authors.forename: Erdogan
authors.initials: E
authors.lastname: Cetinkaya
authors.forename: Onur
authors.initials: O
authors.lastname: Turan
authors.forename: Atila
authors.initials: A
authors.lastname: Akkoclu
authors.forename: Armagan
authors.initials: A
authors.lastname: Hazar
authors.forename: Nurdan
authors.initials: N
authors.lastname: Kokturk
authors.forename: Haluk Celalettin
authors.initials: HC
authors.lastname: Calisir
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000453:epidemiology; D015994:Incidence; D017563:Lung Diseases, Interstitial / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D017565:Sarcoidosis, Pulmonary / Q000453:epidemiology; D014421:Turkey / Q000453:epidemiology
keywords: distribution; epidemiology; incidence; interstitial lung diseases