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

Abstract

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 PM 2.5 and PM 10 at the workplaces of these women. Methods: A comparative cross-sectional design. Questionnaire was administered; spirometry was performed; PM 2.5 and PM 10 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. PM 2.5 levels at the cassava processing plants were (50 ± 10.0 μg/m 3 ) while the levels at the petty traders' stalls were 13.0 ± 10.0 μg/m 3 (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. 42of 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,, age group 50 years -60 years (OR 6.805,) and working as a cassava processor for ≥10 years (OR 14.916,.820) compared to <10 years. Conclusion: Cassava processors are exposed to very high levels of PM 2.5 , 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.

Spirometric Indices of Charcoal Smoke Exposed Food Grillers in Yenagoa South-South, Nigeria

“…Several studies 14,15,16,17 have demonstrated an association between biomass fume exposure and the development of obstructive airway disease. One of the first associations of biomass smoke with obstructive lung disease was reported by Woolcock et al 18 in New Guinea.…”

Exposure to Wood Smoke and Associated Health Effects in Sub-Saharan Africa: A Systematic Review

“…Occupational exposure to wood smoke were reported in seven studies. These include charcoal production [17][18], bakery [44], fish drying [20,50], garri (cassava) processing [21] and street cooking [38].…”

“…All the seven studies on lung function [20-21, 38, 57-60] reported positive association between wood smoke exposure and reduced lung function. Three of these studies [20][21]38] reported reduced lung function [20] or higher risk of obstructive pulmonary defect [21,38] in women occupationally exposed to wood smoke. With reference to those who have worked as cassava processors for less than 10 years, working as cassava processor for more than 10 years was associated with higher risk (OR: 14.916, 95% CI: 5.077-43.820) of obstructive pulmonary defect [21].…”

“…From the reviewed studies, the reported sources of wood smoke exposure in sub-Saharan Africa were mostly through use of wood fuels in domestic cooking. Occupational exposure to wood smoke was reported in seven studies and included the use of wood fuels in bakery [44] commercial fish drying [20,50], cassava (garri) processing [21], street cooking [38] and charcoal production [17][18]. Generally, in SSA, more than 90% of households (especially those living in rural areas) rely on wood fuels as the only source of energy for all their cooking needs [10].…”

“…Higher level of exposure may be seen in individuals with some occupations. These include wild land fire fighters [15], charcoal producers [16][17][18], farmers involved in agricultural burnings [2] and individuals involved in commercial cooking and food processing using wood fuel [19][20][21]. Other significant sources of exposure may include bushfires, consumption of food items preserved or processed with wood smoke [19,[22][23] and the ambient air [24][25].…”