Urinary glyphosate levels and association with mortality in the 2013-16 National Health and Nutrition Examination Survey.

Abstract

Glyphosate is the most commonly used herbicide in the USA; however, its safety is still under debate. We assessed glyphosate levels and their association with overall mortality in a representative sample of the US adult population from the 2013 to 2016 National Health and Nutrition Examination Survey. We extracted data on urinary glyphosate (N = 2910) measured by ion chromatography isotope-dilution tandem mass spectrometry. Associations between glyphosate concentrations and demographic, lifestyle and other exposures were analyzed. Data were linked to public-use Mortality Files for 2019. The mean (STD) glyphosate level was 0.53 (0.59) ng/ml, with 25.7% of the subjects having glyphosate levels at or below the detection limit. At multivariate analysis, age and creatinine were associated with glyphosate urinary levels (both P < 0.0001). There was a borderline association between glyphosate levels and mortality (HRadj 1.33; 95% CI 0.99-1.77 P = 0.06). When 3,5,6-trichloropyridinol was excluded from the Cox model, glyphosate exhibits a significant association with mortality (HRadj 1.33; 95% CI 1.00-1.77; P = 0.0532). These nationally representative data suggest that recent exposure to glyphosate could be associated with increased mortality. More studies are necessary to understand population-level risk associated with the product, given its widespread use in agriculture.