Multiple Risk Exposure and Chronic Obstructive Pulmonary Disease Characteristics among Men in a Mining Community in Northern Tanzania

Abstract

Background: COPD contributes to a substantial burden of diseases globally. The existing unregulated small scale mining activities in Africa could expose miners to excessive air pollution levels and subsequent development of COPD. The understanding of the co-existent multiple risk factors for COPD is crucial for local public health action.

Methods: We conducted a cross-sectional study in a small-scale, informal mining site Tanzania. We recruited eligible active miners, ex-miners and non-miners aged ≥30 years. We assessed respiratory symptoms and risk factors and performed spirometry, with COPD defined based on post-bronchodilator FEV₁/FVC<70%. We monitored air pollution based on PM₁₀ level in mining pits using TSI Side Pak^TM AM510 samplers.

Results: A total of 702 men [480 active miners, 170 ex-miners and 52 non-miners⦌ were recruited with a mean age of 40.95 ± 9.21 years and two-thirds were cigarette smokers. The prevalence of COPD was estimated at 15.20%, 17.10% and 15.40% for active miners, ex-miners and non-miners respectively. Over 18% of current cigarette smokers had significant nicotine dependence which was associated with the duration of smoking (p= 0.028) and the number of pack years (p = 0.002). The majority of COPD patients presented with cough and had frequent exacerbations but with mild to moderate airway limitation. The survey revealed up to 20,000µg/m³ of PM₁₀ in the underground microenvironment exceedingly higher than the acceptable limits.

Conclusion: The prevalence of COPD among the mining communities is substantial in Tanzania. The patients are largely young and many smoke cigarettes. The mining activities are typically carried out without protective gear. A multifactorial approach is critical in the prevention of COPD in this community.