Environmental Pyrethroid Exposure and Cognitive Dysfunction in U.S. Older Adults: The NHANES 2001–2002

Pyrethroid compounds are widely used in household insecticides and agricultural pesticides. Recent studies, however, report that pyrethroid exposures affect neurobehavioral function in animals and may be associated with adverse neurocognitive development in children. This study aimed to examine the association between pyrethroid exposure and cognitive dysfunction in older adults using a well-defined general population. We analyzed data from 336 individuals, aged 60-84 years, who participated in the National Health and Nutrition Examination Survey 2001-2002. We used urinary 3-phenoxybenzoic acid (3-PBA) concentration as a biomarker of pyrethroid exposures and assessed cognitive function with the digit-symbol coding test. The geometric means (±geometric standard errors) of creatinine-uncorrected and corrected urinary 3-PBA were 0.30 (±0.87) μg/L and 0.36 (±0.89) μg/g. After adjusting for sociodemographic factors, higher 3-PBA concentrations (> vs. ≤0.30 μg/g creatinine (median)) were associated with lower scores of cognitive function (-3.83 95% confidence interval: -7.11, -0.54). Significance was persistent after additionally adjusting for physical activity and smoking pack-year (-3.76 95% CI: -7.16, -0.36) and further adjusting for BMI and presence of hypertension and diabetes (-3.82 95% CI: -6.92, -0.71). Our findings suggest that pyrethroid exposure is associated with cognitive dysfunction in older adults.