The association between chronic airflow obstruction and poverty in 12 sites of the multinational BOLD study

Poverty is strongly associated with mortality from COPD, but little is known of its relation to airflow obstruction. In a cross-sectional study of adults aged >= 40 years from 12 sites (N=9255), participating in the Burden of Obstructive Lung Disease (BOLD) study, poverty was evaluated using a wealth score (0-10) based on household assets. Obstruction, measured as forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) (%) after administration of 200 mu g salbutamol, and prevalence of FEV1/FVC< lower limit of normal were tested for association with poverty for each site, and the results were combined by meta-analysis. Mean wealth scores ranged from 4 in Blantyre (Malawi) and Kashmir (India) to 10 in Riyadh (Saudi Arabia), and the prevalence of obstruction, from 16% in Kashmir to 3% in Riyadh and Penang (Malaysia). Following adjustments for age and sex, FEV1/FVC increased by 0.36% (absolute change) (95% CI: 0.22, 0.49; p<0.001) per unit increase in wealth score. Adjustments for other confounders reduced this effect to 0.23% (0.11, 0.34), but even this value remained highly significant (p<0.001). Results were consistent across sites (I-2=1%; p(het)=0.44). Mean wealth scores explained 38% of the variation in mean FEV1/FVC between sites (r(2)=0.385, p=0.031). Airflow obstruction is consistently associated with poverty at individual and community levels across several countries.