Association between glyphosate exposure and cognitive function, depression, and neurological diseases in a representative sample of US adults: NHANES 2013–2014 analysis

Glyphosate, the most widely used herbicide globally, has been linked to neurological impairments in some occupational studies. However, the potential neurotoxic effects of glyphosate exposure in the general population are still not fully understood. We conducted analyses on existing data collected from 1532 adults of the 2013-2014 National Health and Nutrition Examination Survey (NHANES) to explore the possible relationship between glyphosate exposure and cognitive function, depressive symptoms, disability, and neurological medical conditions. Our results showed a significant negative association between urinary glyphosate levels and the Consortium to Establish a Registry for Alzheimer's Disease Word List Memory Test (CERAD-WLT) trial 3 recall and delayed recall scores in both models, with ß coefficients of -0.288 (S.E. = 0.111, P = 0.021) and -0.426 (S.E. = 0.148, P = 0.011), respectively. Furthermore, the odds ratio did not show a significant increase with the severity of depressive symptoms with a one-unit increase in ln-glyphosate levels. However, the odds ratio for severe depressive symptoms was significantly higher than for no symptoms (odds ratio = 4.148 (95% CI = 1.009-17.133), P = 0.049). Notably, the odds ratio showed a significant increase for individuals with serious hearing difficulty (odds ratio = 1.354 (95% CI = 1.018-1.800), P = 0.039) with a one-unit increase in ln-glyphosate levels, but not for other neurological medical conditions. In conclusion, our findings provide the first evidence that glyphosate exposure may be associated with neurological health outcomes in the US adult population. Additional investigation is necessary to understand the potential mechanisms and clinical significance of these correlations.