Assessment of paper dust exposure and chronic respiratory symptoms among paper factory workers in, Ethiopia; a comparative cross-sectional study

Abstract Background Workers in pulp and paper factories are continuously exposed to paper dust. Excessive exposure to paper dust can cause respiratory disease. Information about the prevalence of chronic respiratory symptoms and dust exposure levels among workers in pulp and paper factories is not available in Ethiopia. The aim of this study was, therefore, to assess personal total dust exposure levels, the prevalence of chronic respiratory symptoms and their associated risk factors among workers in Ethiopian pulp and paper factories. Methods A comparative cross-sectional study was conducted. A total of 40 dust measurements were carried out on 20 randomly selected workers. To assess chronic respiratory symptoms and associated factors, 434 workers from two paper factories and controls were interviewed using a standard questionnaire adapted from the American Thoracic Society (ATS). Gravimetric analyses of the filters were undertaken using a standard microbalance. Poisson regression was performed for comparing the prevalence of symptoms and risk factors for the two groups. Multivariable analyses were conducted to identify factors associated with chronic respiratory symptoms. Result The arithmetic mean (AM) and geometric mean (GM) of dust exposure levels among the paper factories workers were 11.3 (± 7.7) and 10.2 (± 1.4) mg/m3 respectively. This exposure level exceeded the threshold limit value recommended for total dust (10 mg/m3). The prevalence of having at least one chronic respiratory symptom was about 51% among the workers in paper factories. The prevalence ratio of having chronic respiratory symptoms among paper factory workers was 5.6 times higher (PR = 6, 95% CI 3.5–10.3) than in the controls. Chronic respiratory symptoms were significantly associated with factors such as an educational status of less than grade 9, being employed in the work sections of the factories, having work experience of 5 years and above, working more than 8 h per day and having a past history of occupation and respiratory illnesses. Conclusion The dust concentration in the paper factories exceeded the acceptable recommended limit value of 10 mg/m3. The prevalence of chronic respiratory symptoms among paper factory workers was higher than among controls. The main determining factors for chronic respiratory symptoms among the workers were the specific work section such as production section, low income, having past history of respiratory illnesses, the number of years of working and low educational status. This finding indicated the need for improving the working conditions in paper factories in Ethiopia.