Introduction Hodgkin lymphoma is a rare cancer of B-lymphocytes diagnosed in approximately 80,000 individuals worldwide each year. While the use of some pesticides may increase the risk of other lymphoid malignancies, associations with Hodgkin lymphoma remain poorly understood.

Objectives We investigated associations of use of 22 pesticide active ingredients and 13 chemical groups with Hodgkin lymphoma incidence in three large agricultural cohorts from France, Norway and the USA participating in an international consortium of agricultural cohorts (AGRICOH).

Methods Use of each active ingredient was estimated from self-report (USA) or crop production combined with crop pesticide exposure matrices (France and Norway). Multivariable Cox regression was used to estimate overall and age-stratified ( adjusted for exposure to other pesticides and other potential confounders. Cohort-specific estimates were combined using random effects meta-analysis.

Results Among 316,270 farmers (75% male), 63% had ever used at least one pesticide, and 91 incident Hodgkin lymphoma cases were diagnosed during follow-up from 1993 to 2011 (3,574,815 person-years). Risks were elevated in association with use of the herbicide dicamba (meta-HR=1.63, 95% CI: 0.83–3.22; 35 exposed cases), DDT (meta-HR=1.79, 95% CI: 0.73–4.37; 27 exposed cases), and the synthetic pyrethroid insecticides deltamethrin (meta-HR=1.86, 95% CI: 0.76–4.52; 25 exposed cases) and esfenvalerate (meta-HR=1.86, 95% CI: 0.78–4.43; 22 exposed cases), though precision was low.

Conclusion This was the largest effort from prospective studies to evaluate associations between the use of specific pesticides and the risk of Hodgkin lymphoma. Nevertheless, analyses were relatively underpowered due to low numbers of exposed cases. Future studies should aim to include data on Hodgkin lymphoma incidence among younger farmers and strive to further refine exposure assessment methods.