Non-communicable Lung Disease in Sub Saharan Africa: a Community-based Cross-sectional Study of Adults in Urban Malawi

Rationale Non-communicable diseases (NCD) are major causes of morbidity and mortality in sub-Saharan Africa (sSA). Valid burden of disease estimates are lacking for non-communicable lung disease in sSA. Objectives We performed a community-based survey to determine the prevalence of chronic lung disease amongst adults ≥18 years in Malawi, using ATS standard spirometry, internationally validated respiratory symptom and exposure questionnaires, and including assessment of HIV-status. Methods An age and gender stratified random sample of 2000 adults was taken from the population of Chilomoni district of Blantyre, Malawi. Fieldworkers collected questionnaire data, conducted HIV-testing and performed pre/post bronchodilator spirometry on eligible participants. Survey-weighted population prevalence estimates of respiratory symptoms and spirometric abnormalities were computed, and bivariate and multivariable regression were used to identify associated variables. Results Questionnaire data, HIV status and BOLD standard spirometry were obtained from 1059, 937 and 749 participants respectively. Current respiratory symptoms, exposure to biomass and ever smoking were reported by 11.8%, 85.2% and 10.4% respectively. HIV prevalence was 24.2%. Moderate-severe airway obstruction was seen in 3.6%. The prevalence of spirometric restriction was 38.6% using NHANES reference ranges and 9.0% using local reference ranges. Age was positively associated with obstruction while low BMI was associated with restriction. Conclusions Over 40% of the Malawian adults in our urban population-representative sample had abnormal lung function (mostly restrictive) in the context of widespread exposure to biomass smoke and high HIV prevalence. These findings have potentially major pubic health implications for Malawi and the broader sSA region