Biomonitoring of acetylcholinesterase inhibition among agricultural workers exposed to pesticides in Tanzania: a cross-sectional study
5 affiliations
- 1Department of Global Health and Biomedical Sciences, Nelson Mandela African Institution of Science and Technology
- 2Directorate of Pesticide Management, Tanzania Plant Health and Pesticide Authority (TPHPA)
- 3Department of Internal Medicine, Kilimanjaro Christian Medical Centre
- 4Population Health Sciences Institute, Newcastle University
- 5Food and Agriculture Organization of the United Nations (FAO)
Abstract
Background Agricultural workers in Tanzania face substantial occupational health risks associated with pesticide exposure, yet national biomonitoring data remain limited. Organophosphate and carbamate pesticides inhibit acetylcholinesterase (AChE), an established biomarker of pesticide exposure and early biological effect. This study evaluated erythrocyte AChE inhibition among agricultural workers across multiple farming systems and geographic regions in Tanzania. Methods A cross-sectional study was conducted between January 2020 and December 2025 within the framework of occupational safety assessments coordinated by the Tanzania Plant Health and Pesticides Authority (TPHPA). A total of 1,387 agricultural workers from Arusha, Kilimanjaro, Morogoro, Mbeya/Songwe, and Coastal regions were recruited using multistage stratified sampling. Participants were classified as pesticide-exposed workers if they directly handled pesticides during agricultural activities and as apparently unexposed workers if they had no direct occupational pesticide handling responsibilities. Erythrocyte AChE activity was measured using the Test-mate ChE Cholinesterase Test System (Model 400). Statistical analyses included independent-samples t-tests, one-way and two-way analysis of variance (ANOVA), mixed-effects regression models, Pearson correlation analyses, and Tukey’s Honest Significant Difference post-hoc tests. Results Pesticide-exposed workers had significantly lower AChE levels compared with apparently unexposed workers (21.52 ± 2.41 vs. 28.47 ± 6.93 U/g Hb; mean difference = 6.95 U/g Hb; 95% CI: 6.54–7.36; p < 0.001). Regional differences were observed, with Morogoro recording the lowest mean AChE level and the highest proportion of exposed workers. Sugarcane workers demonstrated lower mean AChE levels than other agricultural sectors. Mixed-effects modeling confirmed that occupational pesticide exposure remained significantly associated with reduced AChE activity after adjustment for farm-level clustering and covariates. Conclusions This study demonstrates a strong association between occupational pesticide exposure and reduced erythrocyte AChE activity among agricultural workers across diverse farming systems in Tanzania. The findings support the integration of routine cholinesterase biomonitoring into occupational health surveillance programs.
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BibTeX
@article{mwezi2026biomonitoring,
title = {{Biomonitoring of acetylcholinesterase inhibition among agricultural workers exposed to pesticides in Tanzania: a cross-sectional study}},
author = {Raphael J. Mwezi and Jones A. Kapeleka and Rosevera Kombo and Yusuph Owanga and Sarah J. Urasa and Marieke C. J. Dekker and William P. Howlet and Richard Walker and Joseph Bukalasa and John-Mary Vianney},
journal = {Journal of Occupational Medicine and Toxicology},
year = {2026},
month = jul,
doi = {10.1186/s12995-026-00520-w},
url = {https://doi.org/10.1186/s12995-026-00520-w},
note = {CC BY},
}
RIS
TY - JOUR
TI - Biomonitoring of acetylcholinesterase inhibition among agricultural workers exposed to pesticides in Tanzania: a cross-sectional study
AU - Raphael J. Mwezi
AU - Jones A. Kapeleka
AU - Rosevera Kombo
AU - Yusuph Owanga
AU - Sarah J. Urasa
AU - Marieke C. J. Dekker
AU - William P. Howlet
AU - Richard Walker
AU - Joseph Bukalasa
AU - John-Mary Vianney
PY - 2026
DA - 2026/07/01
JO - Journal of Occupational Medicine and Toxicology
DO - 10.1186/s12995-026-00520-w
UR - https://doi.org/10.1186/s12995-026-00520-w
AB - Background Agricultural workers in Tanzania face substantial occupational health risks associated with pesticide exposure, yet national biomonitoring data remain limited. Organophosphate and carbamate pesticides inhibit acetylcholinesterase (AChE), an established biomarker of pesticide exposure and early biological effect. This study evaluated erythrocyte AChE inhibition among agricultural workers across multiple farming systems and geographic regions in Tanzania. Methods A cross-sectional study was conducted between January 2020 and December 2025 within the framework of occupational safety assessments coordinated by the Tanzania Plant Health and Pesticides Authority (TPHPA). A total of 1,387 agricultural workers from Arusha, Kilimanjaro, Morogoro, Mbeya/Songwe, and Coastal regions were recruited using multistage stratified sampling. Participants were classified as pesticide-exposed workers if they directly handled pesticides during agricultural activities and as apparently unexposed workers if they had no direct occupational pesticide handling responsibilities. Erythrocyte AChE activity was measured using the Test-mate ChE Cholinesterase Test System (Model 400). Statistical analyses included independent-samples t-tests, one-way and two-way analysis of variance (ANOVA), mixed-effects regression models, Pearson correlation analyses, and Tukey’s Honest Significant Difference post-hoc tests. Results Pesticide-exposed workers had significantly lower AChE levels compared with apparently unexposed workers (21.52 ± 2.41 vs. 28.47 ± 6.93 U/g Hb; mean difference = 6.95 U/g Hb; 95% CI: 6.54–7.36; p < 0.001). Regional differences were observed, with Morogoro recording the lowest mean AChE level and the highest proportion of exposed workers. Sugarcane workers demonstrated lower mean AChE levels than other agricultural sectors. Mixed-effects modeling confirmed that occupational pesticide exposure remained significantly associated with reduced AChE activity after adjustment for farm-level clustering and covariates. Conclusions This study demonstrates a strong association between occupational pesticide exposure and reduced erythrocyte AChE activity among agricultural workers across diverse farming systems in Tanzania. The findings support the integration of routine cholinesterase biomonitoring into occupational health surveillance programs.
SN - 1745-6673
ER -