Environmental burden of disease related to pyrethroid-insecticide exposure and neurodevelopmental toxicity in Europe based on human biomonitoring

Abstract As indicated by human biomonitoring (HBM) studies, exposure to pyrethroids is widespread in Europe with significantly higher exposure observed in children compared to adults. Epidemiological, toxicological, and mechanistic studies raise concerns about potential health effects in humans and, particularly, behavioral disorders such as attention deficit hyperactivity disorder (ADHD) in children at low levels of exposure. Based on an exposure-response function from a single European study and on available quality-assured and harmonized HBM data collected in France, Germany, Iceland, Switzerland, and Israel, an initial estimate of the environmental burden of disease for ADHD associated with pyrethroid exposure (measured by the metabolite 3-phenoxybenzoic acid) was made for individuals aged 0-19 years. The estimated yearly number of prevalence-based disability-adjusted life years (DALYs) per million inhabitants due to ADHD were 34 DALYs for Israel, 26 DALYs for France, 14 DALYs for both Switzerland and Iceland, and 4 DALYs for Germany. Additionally, a substantial number of ADHD cases, averaging 18%, were associated with pyrethroid exposure. Yet, these figures should be interpreted with caution given the uncertainty of some input parameter. In addition to burden of disease estimates due to ADHD, the associated burden of autism-spectrum disorder (ASD) due to pyrethroid exposure and the health economic costs attributable to ADHD and ASD will also be investigated further. To ensure adequate follow-up of policy measures and more robust disease burden estimates, more HBM studies are recommended, along with increased efforts to harmonize the design of epidemiological studies to ensure more meaningful meta-analyses of exposure-response functions. This is particularly important for pyrethroids as more evidence on potential adverse health effects is continuously emerging.