Use of permethrin and other pyrethroids and mortality in the Agricultural Health Study

Pyrethroid insecticides have been linked with multiple health outcomes. One study reported an association with increased all-cause and cardiovascular mortality. Given the widespread use of pyrethroids, these findings warrant confirmation. We explored associations of permethrin/pyrethroid use with overall and cause-specific mortality among 50 665 licensed pesticide applicators in the Agricultural Health Study.

At enrolment (1993-1997), participants self-reported information on permethrin/pyrethroid use. Information on causes of death came from linkage with death registries through 2016. We used Cox proportional hazards models to estimate HRs and 95% CIs with adjustment for potential confounders.

Over an average 21 years of follow-up, 19.6% (9,955) of the cohort died. We found no clear evidence that ever-use of permethrin/pyrethroid was associated with elevated overall mortality or with mortality from most causes examined. There was suggestive evidence, based on a small number of deaths among those exposed, for elevated pyrethroid-associated mortality from some neurological, respiratory and genitourinary diseases in the overall sample and from lung cancer among never-smokers.

Although based on mortality, which is also affected by survival, rather than incidence, these findings are biologically plausible, and future investigations in other populations may be warranted.