Introduction and aim Tobacco farmers are exposed to toxic workplace hazards such as nicotine and pesticides in addition to known agriculture related hazards like dust, and ergonomic factors. Nicotine and pesticide exposure have been linked to the development of chronic respiratory diseases. This study was aimed at determining the prevalence of obstructive lung disease among tobacco farmers in Malawi and its association to nicotine and pesticide exposure. Methods A cross-sectional study was conducted comprising of 279 current workers across four flue-cured tobacco farms in rural Zomba district of Malawi during a tobacco growing season. The assessment involved the use of a modified ECRHS questionnaire and questions on pesticides and nicotine exposure. Voluntary HIV testing was offered to individuals who did not know their HIV status. Health outcomes assessment involved the use of both symptom and spirometry-based diagnoses of obstructive lung disease. The data was analyzed using STATA 14 computer software and included bivariate and multivariate logistic regression analysis. Results The study had predominantly male participants (68%) with a total mean age of 37.7 years, majority (73%) of whom had attained primary education or higher, with 20% being current smokers. Participants had a mean employment duration of 7.3 years and 62% indicated that they worked mainly with tobacco while 57% were involved in pesticides application. HIV prevalence was 16%. The prevalence of current asthma (ECRHS) was 20% whilst for asthma score≥2 it was 23%. The prevalence of chronic bronchitis, work related ocular nasal symptoms and work- related chest symptoms were 17%, 20% and 29%, respectively. Airflow Limitation measured as FEV1 < LLN was 14% (NHANES and sample reference). The prevalence of moderate to severe obstruction was 4%. The prevalence of green tobacco sickness (a proxy for nicotine exposure) in the past year was 26% with an average of 3 episodes within that period. Most workers were exposed to pesticides with 72% reporting exposure during spraying of pesticides while 83% reported re-entry into fields soon after spraying. The main pesticide in use was organophosphates (18%). The majority (51%) of participants reported use of organophosphate pesticides at home. In multivariate analysis nicotine exposure and associated tasks were significantly associated with all respiratory outcomes (OR range 1.78-7.26). Pesticide application was positively associated with all the symptom-based respiratory outcomes (OR 1.96- 2.62) except for work related chest symptoms. Exposure during spraying was significantly associated with asthma score≥2 (OR 2.09, CI 1.01-4.31), current asthma (OR 2.57, CI 1.22-5.40), and work related ocular nasal symptoms (OR 2.43, CI 1.17- 5.04) while pesticide drift was associated with current asthma (OR 2.62, CI 1.00-6.86) and work related ocular nasal symptoms (OR 3.00, CI 1.18-7.62). In spirometry-based outcomes duration of pesticide exposure was significantly associated with FEV1/FVC< LLN (OR 5.11, CI 1.57-16.66), FEV1/FVC< 70% (OR 4.58, CI 1.17-17.98) and moderate to severe obstruction (OR 13.25, CI 1.69-103.93). Nicotine exposure was not significantly associated with spirometry-based outcomes. Conclusion In conclusion, this study showed that tobacco farmers in Malawi have a higher prevalence of asthma and chronic bronchitis compared to the general population or tobacco farmers in other settings. Additionally, exposure to nicotine and pesticides is strongly associated with the prevalence of obstructive lung diseases among these farmers.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uct/oai:localhost:11427/32883 |
| Date | 16 February 2021 |
| Creators | Moyo, Yotam Mgonjetsi |
| Contributors | Adams, Shahieda, Jeebhay, Mohamed |
| Publisher | Faculty of Health Sciences, Department of Public Health and Family Medicine |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Master Thesis, Masters, MPhil |
| Format | application/pdf |
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