Respiratory symptoms related to flour dust exposure are significantly high among small and medium scale flour mill workers in Ethiopia: a comparative cross-sectional survey

BACKGROUND@#International Labour Organization (ILO) report indicates more than 2.4 million workers die from work-related diseases and accidents each year. Work-related respiratory ailments related to airborne particulate matter such as flour dust are responsible for about 386,000 deaths and 6.6 million illness-adjusted life years. Even though exposure to flour dust together with the extreme expansions of flour mill sectors is a priority health concern, extent of the problem is little investigated in Ethiopia. The aim of this study was to evaluate the magnitude and risk factors of work-related respiratory symptoms among flour mill workers in Bahir Dar City, Ethiopia.@*METHODS@#This study employed a comparative cross-sectional survey of 560 samples (280 exposed group from flour mill workers and 280 unexposed group from office workers) with a stratified random sampling technique. The study was conducted from March to April 2019 in Bahir Dar City, Northwest Ethiopia. We used the British Medical Research Council (BMRC) questionnaire to assess work-related respiratory symptoms. The questionnaire was pretested and interview administered to collect data. Binary logistic regression analysis was fitted to evaluate significant factors of respiratory symptoms at a < 0.05 p value. Adjusted odds ratio (AOR) with a confidence interval (CI) of 95% was calculated to determine a strength of association.@*RESULTS@#All the sampled participants had fully responded to the interview. The median age of exposed and unexposed groups was 28.5 interquartile range (IQR, 20) and 31 (IQR, 15) years, respectively. The prevalence of work-related respiratory symptoms among flour mill workers was substantially higher than that of among controls, 63.9% and 20.7%, respectively (Χ@*CONCLUSION@#Respiratory symptoms emanating from exposure to various flour dusts were significantly higher among flour mill workers than among the control group. Therefore, we recommend the need to effectively implement health and safety programs that account for the reduction of dust at a source, use of engineering controls (e.g., provision of adequate ventilation systems), use of administrative measures (e.g., training program and health surveillance) and provision of a suitable personal protective equipment (PPE). Furthermore, it is vital to integrate workplace health and safety programs to the wider public health policies and strategies to effectively mitigate the burden of work-related respiratory conditions. We also encourage future studies to evaluate concentration of flour dusts combined with physical examinations to establish plausible associations of respiratory symptoms with dusts of flour mill-related origin.

Association of MBL With Work-Related Respiratory Symptoms in Bakery Workers

Baker's asthma is the most prevalent occupational asthma, and IgE-mediated response is known as a major pathogenesis. However, recent studies have suggested the involvement of innate immune response because wheat flour contains bacterial endotoxins or lipopolysaccharides. To further understand a role of innate immune response in the development of work-related respiratory symptoms (WRS) in bakery workers, we investigated mannose-binding lectin (MBL), one of the initiating components of the complement cascade in a single cohort of bakery workers. A total of 373 bakery workers completed a questionnaire regarding WRS. The bakery workers were divided into 2 groups according to previous history of allergic rhinitis (AR)/bronchial asthma (BA): those with history of AR/BA (group I) and those without (group II). We measured serum MBL levels by using enzyme-linked immunosorbant assay and genotyped 4 single nucleotide polymorphisms of the MBL2 gene (226G>A in exon 1, -554G>C, -431A>C, and -225G>C in the promoter) by using TaqMan assays. Fifty-nine subjects (15.5%) were previously diagnosed with AR/BA, and 64 subjects (16.8%) complained of WRS. No significant differences were found in serum MBL levels between groups I and II. However, in group II subjects, but not in group I subjects, the serum MBL levels were significantly higher in bakery workers with WRS than in those without. In addition, the serum MBL levels were significantly different according to genetic polymorphisms of the MBL2 gene and its haplotypes. In conclusion, serum MBL, affected by genetic polymorphisms, may be associated with WRS in bakery workers with no previous history of AR/BA.