Tahmaz, N, Soutar, A, Cherrie, J W · The Annals of occupational hygiene · 2003 · DOI
This study looked at sheep farmers in the UK who reported health problems they believed were caused by pesticides used in sheep dipping. Researchers wanted to know if repeated exposure to these pesticides was linked to chronic fatigue. They found that fatigue was very common among farmers who thought pesticides affected their health, and there was some association between higher pesticide exposure and higher fatigue scores, though the evidence was limited.
This study addresses an important gap for ME/CFS patients exposed to pesticides and environmental toxins. It provides preliminary evidence that occupational pesticide exposure in farming may be associated with chronic fatigue symptoms, supporting the need for further investigation into environmental triggers in ME/CFS. The findings validate patient concerns about pesticide exposure while highlighting that more rigorous research is needed to understand these potential links.
This study does not establish a causal relationship between organophosphate exposure and chronic fatigue—it shows only an association among self-selected farmers who already believed pesticides affected their health. The low response rate (37%) and lack of an unexposed control group limit generalizability. The study cannot rule out confounding factors or reverse causality, and the authors themselves concluded the evidence for a link is limited despite the observed associations.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Tahmaz, N, Soutar, A, & Cherrie, J W (2003). Chronic fatigue and organophosphate pesticides in sheep farming: a retrospective study amongst people reporting to a UK pharmacovigilance scheme.. The Annals of occupational hygiene. https://doi.org/10.1093/annhyg/meg042
BibTeX
@article{mecfsatlas-tahmaz-2003-chronic-fatigue,
author = {Tahmaz, N and Soutar, A and Cherrie, J W},
title = {Chronic fatigue and organophosphate pesticides in sheep farming: a retrospective study amongst people reporting to a UK pharmacovigilance scheme.},
journal = {The Annals of occupational hygiene},
year = {2003},
doi = {10.1093/annhyg/meg042},
note = {PubMed: 12765866},
url = {https://www.mecfsatlas.com/evidence/tahmaz-2003-chronic-fatigue},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-29. https://www.mecfsatlas.com/evidence/tahmaz-2003-chronic-fatigue
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