Occupational Exposure to Particulate Matter from Biomass Smoke and Its Relationship to Respiratory Symptoms and Pulmonary Function among Rural Women Involved in Cassava Processing in Nigeria

Background: Cassava processing is an important source of livelihood for many rural women and involves prolonged exposure to biomass smoke. The impact of this exposure on respiratory health of these women has not been explored. We aimed to compare the frequency of respiratory symptoms and pulmonary function among cassava processing women to that of petty traders as well as the levels of particulate matter PM2.5 and PM10 at the workplaces of these women. Methods: A comparative cross-sectional design. Questionnaire was administered; spirometry was performed; PM2.5 and PM10 were sampled. Descriptive statistics were used and multiple logistic regressions were performed to assess the relationship between predictors and outcome variables. Results: 528 non-smoking women were recruited (264 cassava processors and 264 petty traders). The women were matched by baseline parameters. PM2.5 levels at the cassava processing plants were (50 ± 10.0 μg/m3) while the levels at the petty traders’ stalls were 13.0 ± 10.0 μg/m3 (P < 0.001). One-year prevalence of respiratory symptoms among cassava processors compared to petty traders was as follows: cough 22.7% versus 9.5% (P < 0.001), chronic bronchitis 5.7% versus 2.3% (P = 0.045), phlegm 23.1% versus 11%, wheezing 10.2% versus 5.3% (P = 0.05), breathlessness 36% versus 30.7% (P = 0.230). The mean (standard deviation) of Forced Vital Capacity (FVC) of 2.11 ± 0.37 liters, Forced Expiratory Volume in one second (FEV1) of 1.58 ± 0.38 liters and FEV1/FVC of 74.12% ± 7.55% among cassava processors was significantly lower than FVC of 2.19 ± 0.28 liters, FEV1 of 1.72 ± 0.26 liters and FEV1/FVC of 78.34% ± 5.05% among petty traders (P = 0.007, <0.001, <0.001 and <0.001 respectively). Prevalence of obstructive pulmonary defect (FEV1/FVC < 70%) among the cassava processors was 21.3% compared to 6.4% among petty traders (P < 0.001). The factors that predicted an obstructive pulmonary defect were occupational biomass fuel use (OR 6.101, CI 3.212 - 11.590), age group 50 years - 60 years (OR 6.805, CI 1.764 - 26.235) and working as a cassava processor for ≥10 years (OR 14.916, CI 5.077 - 43.820) compared to <10 years. Conclusion: Cassava processors are exposed to very high levels of PM2.5, having more respiratory symptoms, lower pulmonary function parameters and higher frequency of obstructive pulmonary defect compared to women not occupationally exposed to biomass. Use of more efficient fuel in cassava processing and personal protective equipment may limit the harmful health effects of biomass among these vulnerable women.