Association between pyrethroids exposure and risk of depressive symptoms among adults in the U.S.

Abstract This study aimed to investigate the association between pyrethroid exposure and the risk of depressive symptoms in adults in the US. Data of participants aged ≥ 20 years (n = 6402) from the National Health and Nutrition Examination Survey (NHANES, 2007–2014) were included. 3-phenoxybenzoic acid (3-PBA), an adequately detected pyrethroid metabolite, was used as a biomarker to assess pyrethroid exposure. Depressive symptoms were defined as a total score ≥ 10 using the Patient’s Health Questionnaire (PHQ-9). Multivariable logistic regression analyses were performed to examine the association between urinary 3-PBA levels and the risk of depressive symptoms. In this study, 617 participants (weighted frequency, 8.31%) developed depressive symptoms. There was a significant positive association between ln-transformed 3-PBA and depressive symptoms after adjustment for all covariates and the weighted OR was 1.10 (95% CI, 1.03–1.18; P = 0.009). Participants in the highest tertile have a higher risk of depressive symptoms than those in the lowest tertile of urinary 3-PBA and weighted OR of 1.24 (95% CI, 0.95–1.61; P = 0.015). Restricted cubic spline showed a nonlinear association between urinary 3-PBA and depressive symptoms (P for nonlinearity = 0.016). Subgroup analysis showed a significant interaction between trouble sleeping and urinary 3-PBA levels on the risk of depressive symptoms (P for interaction = 0.005).