Bagasse dust exposure and chronic respiratory symptoms among workers in the Metehara and Wonji sugar factories in Ethiopia: a longitudinal study design

BACKGROUND: Ethiopia’s sugar factories are growing by creating job opportunities for thousands of workers with varying educational, professional and socioeconomic backgrounds. These sugar factories are a source of several hazards that severely harm the workers’ health. In this context, there is inconclusive evidence on the level of bagasse dust exposure and chronic respiratory health symptoms. This study aimed to assess the degree of bagasse dust exposure and chronic respiratory health symptoms. METHODS: In this longitudinal study, five workstations were selected for dust sampling. A stratified random sampling technique was used to select 1043 participants. We measured the dust intensity using a calibrated handheld real-time dust monitor once a month for 5 months, totalling 50 dust samples. Chronic respiratory symptoms were assessed using the American Thoracic Society’s respiratory symptoms questionnaire. RESULTS: A 1 hour time-weighted average of bagasse dust intensity in the boiler, power turbine and evaporation plant was 8.93 mg/m(3), 8.88 mg/m(3) and 8.68 mg/m(3), respectively. This corresponded to an exposure level to bagasse dust of 85.52% (95% CI 83.2% to 87.6%). The level of chronic respiratory health symptoms was 60.6% (95% CI 59.2% to 61.9%). The most common respiratory symptoms were wheezing (96.8%), coughing (89.7%) and breathlessness (80.9%). The identified risk factors were lack of dust control technology (β= 0.64, 95% CI 0.53 to 0.75), not practising wet spray (β = 0.27, 95% CI 0.21 to 0.41) and not wearing proper respiratory protection devices (β = 0.12, 95% CI 0.30 to 0.56). CONCLUSIONS: Bagasse dust exposure and respiratory health abnormalities were worrying concerns. The absence of dust control technologies and no practice of wet spraying elevated the level of exposure. Not wearing proper respiratory protection gear increased the odds of having respiratory abnormalities. Hence, the use of mechanical solutions to stop dust emissions at their sources and the wearing of proper respiratory protection gear are highly advised.