Lung function variability and the burden of COPD and lung restriction in South Africa and Burkina Faso: results from the AWI-Gen study

BackgroundPopulation-based spirometry data from sub-Saharan Africa remain limited. We characterised lung function, chronic obstructive pulmonary disease (COPD), lung restriction and associated factors from two Sub-Saharan African countries. MethodsWe performed spirometry using ndd Easy On-PC spirometers among adults aged [&ge;]40 years from population-based cohorts in four communities in Burkina Faso and South Africa from January 2019-April 2022. We included 1,619 participants (936 women, 683 men) with repeatable forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). COPD was defined as FEV1/FVC<0.70 and lung restriction as FEV1/FVC[&ge;]0.70, with FVC<80% predicted. We used multivariable models to test factors associated with lung function measurements (FEV1, FVC and FEV1/FVC), COPD and lung restriction. ResultsMedian FEV1 and FVC ranged from 1.940-2.273L and 2.521-2.883L, respectively. COPD prevalence was 16.1% (95% CI 14.4-18.0; site range 10.8%-24.5%) and lung restriction prevalence was 21.3% (95% CI 19.4-23.4; site range 11.3%-36.2%). Prior tuberculosis was associated with higher odds of COPD (OR 2.86, 95% CI 1.75-4.59) and lower FEV1, FVC and FEV1/FVC. HIV infection was associated with higher COPD odds (OR 1.67, 95% CI 1.01-2.72) and lower FEV1/FVC. Hypertension was associated with higher lung restriction odds (OR 1.46, 95% CI 1.07-2.00) and lower FEV1 and FVC. Diabetes was associated with lower COPD odds (OR 0.50, 95% CI 0.24-0.94), lower FVC and higher FEV1/FVC. Ever-smoking and older age were associated with higher COPD odds (OR 2.21, 95% CI 1.48-3.32; OR 1.05, 95% CI 1.03-1.07, respectively); older age was associated with higher lung restriction odds (OR 1.02, 95% CI 1.00-1.04). ConclusionThis multisite study highlights substantial heterogeneity in COPD and lung restriction prevalence across African populations and identifies respiratory multimorbidity with infectious and cardiometabolic conditions. These findings provide population-based evidence to inform respiratory surveillance in sub-Saharan Africa.