Noncommunicable Lung Disease in Sub-Saharan Africa. A Community-based Cross-Sectional Study of Adults in Urban Malawi.

Abstract

Noncommunicable diseases are major causes of morbidity and mortality in sub-Saharan Africa (sSA). Valid burden of disease estimates are lacking for noncommunicable lung disease in sSA. We performed a community-based survey to determine the prevalence of chronic lung disease among adults 18 years or older in Malawi, using American Thoracic Society standard spirometry, internationally validated respiratory symptom and exposure questionnaires, and an assessment of HIV status. An age- and sex-stratified random sample of 2,000 adults was taken from the population of the Chilomoni district of Blantyre, Malawi. Fieldworkers collected questionnaire data, conducted HIV testing, and performed pre- and 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. Questionnaire data, HIV status, and standard spirometry were obtained from 1,059, 933, and 749 participants, respectively. Current respiratory symptoms, exposure to biomass, and ever-smoking were reported by 11.8, 85.2, and 10.4% of participants, respectively. HIV prevalence was 24.2%. Moderate to severe airway obstruction was seen in 3.6%. The prevalence of spirometric restriction was 38.6% using National Health and Nutrition Examination Survey III reference ranges and 9.0% using local reference ranges. Age was positively associated with obstruction, whereas low body mass index was associated with restriction. More than 40% of the Malawian adults in our urban population sample had abnormal lung function (mostly restrictive) in the context of widespread exposure to biomass smoke and a high prevalence of HIV. These findings potentially have major public health implications for Malawi and the broader sSA region.