title: Urbanisation but not biomass fuel smoke exposure is associated with asthma prevalence in four resource-limited settings.
abstract: BACKGROUND
  Urbanisation is an important contributor to the prevalence of asthma worldwide, and the burden of this effect in low-income and middle-income countries undergoing rapid industrialisation appears to be growing. We sought to characterise adult asthma prevalence across four geographically diverse settings in Peru and identify both individual and environmental risk factors associated with adult asthma.
  
  
  METHODS
  We collected sociodemographics, clinical history and spirometry in adults aged ≥35 years. We defined asthma as meeting one of the three criteria: physician diagnosis, self-report of wheezing attack or use of asthma medications. We used multivariable logistic regression to assess individual and environmental factors associated with adult asthma.
  
  
  RESULTS
  We analysed data from 2953 participants (mean age 55 years; 49% male). Overall asthma prevalence was 7.1%, which varied with urbanisation: highest in Lima (14.5%), followed by urban Puno (4.0%), semiurban Tumbes (3.8%) and rural Puno (1.8%). In multivariable analysis, being male (OR=0.60, 95% CI 0.39 to 0.93) and living at high altitude (OR=0.26, 95% CI 0.16 to 0.42) were associated with lower odds of having asthma, whereas living in an urban setting (OR=4.72, 95% CI 3.15 to 7.23) and family history of asthma (OR=1.83, 95% CI 1.19 to 2.73) were associated with higher odds. Current daily exposure to biomass fuel smoke (OR=1.18, 95% CI 0.70 to 1.91) and smoking (OR=0.99, 95% CI 0.73 to 1.22) were not associated with asthma.
  
  
  CONCLUSIONS
  These findings confirm that urbanisation is an environmental risk factor of asthma, questions biomass fuel smoke exposure as an important risk factor and proposes high altitude as possibly protective against the development of asthma.
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Chelsea
authors.initials: C
authors.lastname: Gaviola
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Catherine H
authors.initials: CH
authors.lastname: Miele
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Wise
authors.affiliation: Program in Global Disease Epidemiology and Control, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Gilman
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Devan
authors.initials: D
authors.lastname: Jaganath
authors.affiliation: CRONICAS Center of Excellence in Chronic Diseases, Universidad Peruana Cayetano Heredia, Lima, Peru Department of Medicine, School of Medicine, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: J Jaime
authors.initials: JJ
authors.lastname: Miranda
authors.affiliation: CRONICAS Center of Excellence in Chronic Diseases, Universidad Peruana Cayetano Heredia, Lima, Peru Department of Medicine, School of Medicine, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Antonio
authors.initials: A
authors.lastname: Bernabe-Ortiz
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Nadia N
authors.initials: NN
authors.lastname: Hansel
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA Program in Global Disease Epidemiology and Control, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: William
authors.initials: W
authors.lastname: Checkley
mesh_terms: D000328:Adult; D016902:Air Pollution, Indoor / Q000009:adverse effects*; D001249:Asthma / Q000453:epidemiology* / Q000209:etiology; D018533:Biomass; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010568:Peru / Q000453:epidemiology; D015995:Prevalence; D011379:Prognosis; D012307:Risk Factors; D012424:Rural Population; D012906:Smoke / Q000009:adverse effects*; D013147:Spirometry; D014507:Urbanization
chemical_list: D012906:Smoke
keywords: Asthma; Asthma Epidemiology