Socioeconomic status and COPD among low- and middle-income countries.

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. CONCLUSION: 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.

Prevalence and Determinants of Chronic Obstructive Pulmonary Disease (COPD) in Bangladesh.

RATIONALE: There is a paucity of population-based data on COPD prevalence and its determinants in Bangladesh. OBJECTIVE: To measure COPD prevalence and socioeconomic and lifestyle determinants among ≥40 years Bangladeshi adults. METHODS: In a cross-sectional study, we measured lung function of 3744 randomly selected adults ≥40 years from rural and urban areas in Bangladesh, using a handheld spirometer. COPD was defined according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria as post-bronchodilator ratio of Forced Expiratory Volume in 1st second (FEV1) to Forced Vital Capacity (FVC) < 0.7. In addition, COPD was also assessed by the lower limit of normal (LLN) threshold defined as lower fifth percentile for the predicted FEV1/FVC. RESULTS: The prevalence of COPD was 13.5% by GOLD criteria and 10.3% by LLN criteria. Prevalence of COPD was higher among rural than urban residents and in males than females. More than half of the COPD cases were stage II COPD by both criteria. Milder cases (Stages I and II) were over estimated by the GOLD fixed criteria, but more severe cases (Stages III and IV) were similarly classified. In multiple logistic regression analysis, older age, male sex, illiteracy, underweight, history of smoking (both current and former), history of asthma and solid fuel use were significant predictors of COPD. CONCLUSION: COPD is a highly prevalent and grossly underdiagnosed public health problem in Bangladeshi adults aged 40 years or older. Illiteracy, smoking and biomass fuel burning are modifiable determinants of COPD.