title: The coexistence of asthma and chronic obstructive pulmonary disease (COPD): prevalence and risk factors in young, middle-aged and elderly people from the general population.
abstract: BACKGROUND
  The joint distribution of asthma and chronic obstructive pulmonary disease (COPD) has not been well described. This study aims at determining the prevalence of self-reported physician diagnoses of asthma, COPD and of the asthma-COPD overlap syndrome and to assess whether these conditions share a common set of risk factors.
  
  
  METHODS
  A screening questionnaire on respiratory symptoms, diagnoses and risk factors was administered by mail or phone to random samples of the general Italian population aged 20-44 (n = 5163) 45-64 (n = 2167) and 65-84 (n = 1030) in the frame of the multicentre Gene Environment Interactions in Respiratory Diseases (GEIRD) study.
  
  
  RESULTS
  A physician diagnosis of asthma or COPD (emphysema/chronic bronchitis/COPD) was reported by 13% and 21% of subjects aged <65 and 65-84 years respectively. Aging was associated with a marked decrease in the prevalence of diagnosed asthma (from 8.2% to 1.6%) and with a marked increase in the prevalence of diagnosed COPD (from 3.3% to 13.3%). The prevalence of the overlap of asthma and COPD was 1.6% (1.3%-2.0%), 2.1% (1.5%-2.8%) and 4.5% (3.2%-5.9%) in the 20-44, 45-64 and 65-84 age groups. Subjects with both asthma and COPD diagnoses were more likely to have respiratory symptoms, physical impairment, and to report hospital admissions compared to asthma or COPD alone (p<0.01). Age, sex, education and smoking showed different and sometimes opposite associations with the three conditions.
  
  
  CONCLUSIONS
  Asthma and COPD are common in the general population, and they coexist in a substantial proportion of subjects. The asthma-COPD overlap syndrome represents an important clinical phenotype that deserves more medical attention and further research.
authors.affiliation: Unit of Epidemiology and Medical Statistics, University of Verona, Verona, Italy. roberto.demarco@univr.it
authors.forename: Roberto
authors.initials: R
authors.lastname: de Marco
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Pesce
authors.forename: Alessandro
authors.initials: A
authors.lastname: Marcon
authors.forename: Simone
authors.initials: S
authors.lastname: Accordini
authors.forename: Leonardo
authors.initials: L
authors.lastname: Antonicelli
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Bugiani
authors.forename: Lucio
authors.initials: L
authors.lastname: Casali
authors.forename: Marcello
authors.initials: M
authors.lastname: Ferrari
authors.forename: Gabriele
authors.initials: G
authors.lastname: Nicolini
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Panico
authors.forename: Pietro
authors.initials: P
authors.lastname: Pirina
authors.forename: Maria Elisabetta
authors.initials: ME
authors.lastname: Zanolin
authors.forename: Isa
authors.initials: I
authors.lastname: Cerveri
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Verlato
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000150:complications* / Q000453:epidemiology*; D005260:Female; D006760:Hospitalization; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000453:epidemiology*; D012307:Risk Factors; D057566:Self Report; D055815:Young Adult