Association between pyrethroid exposure and risk of depressive symptoms in the general US adults

Association of pesticide exposure with neurobehavioral outcomes among avocado farmworkers in Mexico

BACKGROUND AND AIM

To date, few studies have focused on the health effects of pesticide exposure among avocado farmworkers. We examined the association of exposure to insecticides, fungicides, and herbicides with cognitive and mental health outcomes among these avocado workers from Michoacan, Mexico.

MATERIALS AND METHODS

We conducted a cross-sectional study of 105 avocado farmworkers between May and August 2021. We collected data on self-reported pesticide use during the 12 months prior to the baseline survey and estimated annual exposure-intensity scores (EIS) using a semi-quantitative exposure algorithm. We calculated specific gravity adjusted average concentrations of 12 insecticide, fungicide, or herbicide metabolites measured in urine samples collected during two study visits (8-10 weeks apart). We assessed participants' cognitive function and psychological distress using the NIH Toolbox Cognition Battery and the Brief Symptom Inventory 18 (BSI-18), respectively. We examined individual associations of EIS and urinary pesticide metabolites with neurobehavioral outcomes using generalized linear regression models. We also implemented Bayesian Weighted Quantile Sum (BWQS) regression to evaluate the association between a pesticide metabolite mixture and neurobehavioral outcomes.

RESULTS

In individual models, after adjusting for multiple comparisons, higher concentrations of hydroxy-tebuconazole (OH-TEB, metabolite of fungicide tebuconazole) were associated with higher anxiety (IRR per two-fold increase in concentrations = 1.26, 95% CI:1.08, 1.48) and Global Severity Index (GSI) (IRR = 1.89, 95% CI:1.36, 2.75) scores, whereas higher concentrations of 3,5,6-trichloro-2-pyridinol (TCPy, metabolite of chlorpyrifos) were associated with lower GSI scores (IRR = 0.69, 95% CI: 0.56, 0.85). In BWQS analyses, we found evidence of a mixture association of urinary pesticide metabolites with higher anxiety (IRR = 1.72, 95% CrI: 1.12, 2.55), depression (IRR = 4.60, 95% CrI: 2.19, 9.43), and GSI (IRR = 1.99, 95% CrI: 1.39, 2.79) scores. OH-TEB and hydroxy-thiabendazole (metabolite of fungicide thiabendazole) combined contributed 54%, 40%, and 54% to the mixture effect in the anxiety symptoms, depression symptoms, and overall psychological distress models, respectively.

CONCLUSIONS

We found that exposure to tebuconazole and thiabendazole, fungicides whose effects have been rarely studied in humans, may be associated with increased psychological distress among avocado farmworkers. We also observed that exposure to chlorpyrifos may be associated with decreased psychological distress.

Association of formaldehyde concentration with depression risk in US adults: a population-based epidemiology study

The association of formaldehyde exposure with depression remains unknown. We used the data from National Health and Nutrition Examination Survey (NHANES) 2015-2016 to evaluate the association between formaldehyde exposure and depression. Multivariable logistic regressions and restricted cubic spline (RCS) were implemented to examine the association between formaldehyde exposure and depression. A total of 1336 participants were included in the analysis, of which 110 (8.23%) participants were depressed. After adjusting for confounders, a significant association between formaldehyde exposure and depression (OR = 1.01, 95% CI: 1.00-1.02, P = 0.043) was observed. The RCS plot showed a positive association in a linear manner (PNonlinear = 0.109), and the risk began to rise rapidly with concentrations above 129.37 nmol/g HB. The positive association remained in participants with high-intensity physical activity (OR = 1.08, 95% CI: 1.02-1.13, P = 0.003), but not in participants with other physical activities. Moreover, we constructed a novel nomogram to easily estimate the individual-specific probabilities of depression. In conclusion, formaldehyde exposure was associated with an elevated risk of depression, and the effect exhibited differences in participants with different levels of physical activity.