Animal farming entails a variety of potential exposures, including infectious agents, endotoxins and pesticides, which may play a role in the aetiology of lymphohaematopoietic cancers (LHCs). The aim of this study was to assess whether farming specific animal species is associated with the risk of overall LHC or its subtypes. Data from three prospective cohort studies in the USA, France and Norway which are part of the Agricultural Cohort consortium and which collected information about animal farming and cancer were used. Analyses included 316 270 farmers and farm workers. Adjusted Cox models were used to investigate the associations of 13 histological subtypes of LHC (n=3282) with self-reported livestock (cattle, pigs and sheep/goats) and poultry (ever/never and numbers raised) farming. Cohort-specific HRs were combined using random-effects meta-analysis. Ever animal farming in general or farming specific animal species was not meta-associated with overall LHC. The risk of myeloid malignancies decreased with increasing number of livestock (p trend=0.01). Increased risk of myeloproliferative neoplasms was seen with increasing number of sheep/goats (p trend <0.01), while a decreased risk was seen with increasing number of livestock (p trend=0.02). Between cohorts, we observed heterogeneity in the association of type of animal farmed and various LHC subtypes. This large-scale study of three prospective agricultural cohorts showed no association between animal farming and LHC risk, but few associations between specific animal species and LHC subtypes were observed. The observed differences in associations by countries warrant further investigations.
- animal workers
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Contributors SE-Z wrote the first draft of the manuscript and provided input on the statistical analyses. GF carried out the statistical analysis. LS, LEBF and ML provided guidance in study design, statistical analyses and manuscript revisions. ST, PL, IB, KK, JS, AM, MB, SK, JH and HK participated in the manuscript preparation. All authors read and approved the final manuscript.
Funding This work was supported by a grant from the Office National de l’Eau et des Milieux Aquatiques (ONEMA), Plan d’action national ECOPHYTO 2018, Axe 3, Volet 4, France. In addition, this work was funded, in part, by the Intramural Research Program of the National Cancer Institute, National Institutes of Health (Z01-CP010119) and the Ammodo van Gogh travel grant VGP.14/20. SE-Z’s work was undertaken during the tenure of an IARC-Australia Postdoctoral Fellowship from the International Agency for Research on Cancer, supported by Cancer Council Australia (CCA). We used the following AHS data releases for this analysis: P1REL201209.0 and P2REL201209.
Disclaimer Where authors are identified as personnel of the International Agency for Research on Cancer/WHO, the authors alone are responsible for the views expressed in this article and they do not necessarily represent the decisions, policy or views of the International Agency for Research on Cancer/WHO.
Competing interests None declared.
Ethics approval All studies received approval from the relevant institutional or regional ethical committee.
Provenance and peer review Not commissioned; externally peer reviewed.
Patient consent for publication Not required.
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