title: Socioeconomic status and COPD among low- and middle-income countries.
abstract: BACKGROUND
  Socioeconomic status (SES) is a strong social determinant of health. There remains a limited understanding of the association between SES and COPD prevalence among low- and middle-income countries where the majority of COPD-related morbidity and mortality occurs. We examined the association between SES and COPD prevalence using data collected in Argentina, Bangladesh, Chile, Peru, and Uruguay.
  
  
  METHODS
  We compiled lung function, demographic, and SES data from three population-based studies for 11,042 participants aged 35-95 years. We used multivariable alternating logistic regressions to study the association between COPD prevalence and SES indicators adjusted for age, sex, self-reported daily smoking, and biomass fuel smoke exposure. Principal component analysis was performed on monthly household income, household size, and education to create a composite SES index.
  
  
  RESULTS
  Overall COPD prevalence was 9.2%, ranging from 1.7% to 15.4% across sites. The adjusted odds ratio of having COPD was lower for people who completed secondary school (odds ratio [OR] =0.73, 95% CI 0.55-0.98) and lower with higher monthly household income (OR =0.96 per category, 95% CI 0.93-0.99). When combining SES factors into a composite index, we found that the odds of having COPD was greater with lower SES (interquartile OR =1.23, 95% CI 1.05-1.43) even after controlling for subject-specific factors and environmental exposures.
  
  
  CONCLUSIONS
  In this analysis of multiple population-based studies, lower education, lower household income, and lower composite SES index were associated with COPD. Since household income may be underestimated in population studies, adding household size and education into a composite index may provide a better surrogate for SES.
authors: Division of Pulmonary and Critical Care, School of Medicine; Program in Global Disease Epidemiology and Control, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
authors: Matthew
authors: M
authors: Grigsby
authors: Division of Pulmonary and Critical Care, School of Medicine.
authors: Trishul
authors: T
authors: Siddharthan
authors: Centre for Control of Chronic Diseases, icddr,b, Dhaka, Bangladesh.
authors: Muhammad Ah
authors: MA
authors: Chowdhury
authors: Centre for Control of Chronic Diseases, icddr,b, Dhaka, Bangladesh.
authors: Ali
authors: A
authors: Siddiquee
authors: Institute for Clinical Effectiveness and Health Policy, Buenos Aires, Argentina.
authors: Adolfo
authors: A
authors: Rubinstein
authors: Institute for Clinical Effectiveness and Health Policy, Buenos Aires, Argentina.
authors: Edgardo
authors: E
authors: Sobrino
authors: CRONICAS Centre of Excellence for Chronic Diseases, Universidad Peruana Cayetano Heredia; Department of Medicine, School of Medicine, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors: J Jaime
authors: JJ
authors: Miranda
authors: CRONICAS Centre of Excellence for Chronic Diseases, Universidad Peruana Cayetano Heredia.
authors: Antonio
authors: A
authors: Bernabe-Ortiz
authors: Faculty of Health, School of Kinesiology and Health Science, York University, Toronto, ON, Canada.
authors: Dewan
authors: D
authors: Alam
authors: Division of Pulmonary and Critical Care, School of Medicine; Program in Global Disease Epidemiology and Control, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
authors: William
authors: W
authors: Checkley
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001459:Bangladesh / Q000453:epidemiology; D003906:Developing Countries / Q000191:economics; D004522:Educational Status; D005191:Family Characteristics; D005260:Female; D054624:Health Status Disparities; D006801:Humans; D007182:Income; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011203:Poverty / Q000191:economics; D015995:Prevalence; D025341:Principal Component Analysis; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000191:economics / Q000453:epidemiology*; D012307:Risk Factors; D012959:Socioeconomic Factors; D013020:South America / Q000453:epidemiology
keywords: COPD; low- and middle-income country; socioeconomic status