Chronic airflow obstruction in Tanzania - a cross-sectional study

Background: Chronic obstructive pulmonary disease is a global problem and available data from sub-Saharan Africa is very limited. Methods: A cross-sectional facility-based pilot study among patients and visitors to an urban and a rural primary healthcare facility was conducted in coastal Tanzania. The primary outcome was the prevalence of chronic airflow obstruction. Results: The final analysis included 598 participants with valid post-bronchodilator spirometry. Applying ATS/ERS spirometric criteria, chronic airflow obstruction was found in n = 24 (4%, CI95 2.7-5.9) participants and in n = 30 (5%, CI95 3.5-7.1) applying GOLD spirometric criteria. To analyse risk factors for chronic airflow obstruction including those not meeting ATS/ERS or GOLD criteria, FEF25-75 and FEV1% predicted was analysed in participants without evidence of pulmonary restriction among those exposed or not exposed to risk factors (n = 552). FEV1% predicted, but in particular FEF25-75 decreased with increasing symptom severity of shortness of breath as well as limitations in daily activities of participants. Cooking in general and cooking with biomass fuels vs. gas or electricity was associated with significantly lower FEF25-75, but not with lower FEV1% predicted. Participants having refrained from taking a job because of shortness of breath exhibited lower FEF25-75 (p < 0.01). A history of prior active TB was the most relevant risk factor associated with a decrease in FEF25-75 as well as FEV1% predicted. Conclusion: This study demonstrated a relevant prevalence of chronic airflow obstruction in primary healthcare attendants and healthy visitors of a Tanzanian hospital. Using the baseline data provided, larger and populationbased studies are needed to validate these findings. TB may have more impact on development of chronic airway obstruction than smoking in Africa. Due to the influence of age on the GOLD definition of chronic airflow obstruction, studies should report results using both ATS/ERS and GOLD definitions and include age-stratified analysis. Analysis of FEV1 and in particular FEF25-75 may yield additional information on risk factors and earlier stages of chronic airflow obstruction.