Pesticide use and risk of non-Hodgkin lymphoid malignancies in agricultural cohorts from France, Norway and the USA: a pooled analysis from the AGRICOH consortium.
Level 3 - non-randomized controlled study
Pooled analysis of prospective cohort studies
PubMed 30880337 · doi:10.1093/ije/dyz017
What was done
Researchers conducted a pooled analysis of three prospective agricultural worker cohorts from France, Norway, and the United States (AGRICOH consortium) to evaluate associations between pesticide use and non-Hodgkin lymphoid malignancies (NHL) overall and by subtype. They examined ever-use of 14 pesticide chemical groups and 33 active chemical ingredients. Exposure was determined through self-reported crop histories combined with crop-exposure matrices (France, Norway) or self-reported lifetime active ingredient use (USA). Cohort-specific hazard ratios (HRs) and 95% confidence intervals (CIs) from Cox regression models were combined via random-effects meta-analysis with adjustment for co-exposure to other pesticides.
What was found
Among 316,270 farmers followed for 3,574,815 person-years, 2,430 incident NHL cases were diagnosed. Most evaluated pesticides showed no statistically significant association with NHL. Moderately elevated meta-HRs were found for NHL overall with terbufos (meta-HR 1.18, 95% CI 1.00-1.39), chronic lymphocytic leukaemia/small lymphocytic lymphoma with deltamethrin (meta-HR 1.48, 95% CI 1.06-2.07), and diffuse large B-cell lymphoma with glyphosate (meta-HR 1.36, 95% CI 1.00-1.85). Inverse associations with overall NHL were observed for broader groups of organochlorine insecticides (meta-HR 0.86, 95% CI 0.74-0.99) and phenoxy herbicides (meta-HR 0.81, 95% CI 0.67-0.98), though not for specific active ingredients within those classes.
Why it matters
This large international consortium suggests that pesticide-associated risks for lymphoid malignancies are largely chemical- and subtype-specific rather than universal across chemical classes.
Limits
Exposure assessment relied on self-reported histories and crop-exposure matrices, introducing non-differential exposure misclassification. The primary analyses evaluated ever versus never exposure rather than quantitative exposure-response relationships, and multiple comparisons across 33 chemicals and multiple lymphoma subtypes increase the potential for chance findings.
Cited by
- context Non-Hodgkin's lymphoma is correlated with exposure to glyphosate.