Neonicotinoid Insecticides and Their Characteristic Metabolites may Induce High Fasting Blood Glucose and Obesity in Human

Neonicotinoid insecticides (NEOs) find widespread application globally as a safeguard for agricultural production. While these pollutants exhibit toxicity towards non-target organisms and pose potential risks to human health, there is a noticeable dearth of studies documenting the adverse effects of neonicotinoid insecticides (NEOs) specifically in humans. In this study, the concentrations of six NEOs and their five metabolites were measured in the blood samples collected from the normal (n = 130) and obesity (n = 130) cohorts in South China. An evaluation was undertaken to examine the associations between the levels of target analytes and either fasting blood glucose (FBG) or the condition of being overweight. Results showed that the NEOs and their metabolites were frequently detected (63–100%) in both cohorts, with median levels of 0.01–4.32 ng/mL. Discernible gender-related disparities were noted within the blood samples, manifesting as elevated concentrations of the majority of NEOs and their metabolites in females compared to males. In addition, there were positive correlations between the concentrations of IMI_eq (imidacloprid equivalent, calculated using the relative potency factors of NEOs and their metabolites) and 1-methyl-3-(tetrahydro-3-furylmethyl) urea (UF, a metabolite of dinotefuran) with FBG levels (3.28 ng/mL vs. 4.32 ng/mL for UF, and 34.6 ng/mL vs. 40.6 ng/mL for IMI_eq). Moreover, significant associations were found between UF [odds ratio 1.78, 95% confidence interval (CI) 0.86–4.66, p < 0.01] and IMI_eq (odds ratio 1.66, 95% CI 0.94–3.56, p < 0.01) concentrations and being overweight. Our findings indicated that human exposure to NEOs and their metabolites may induce high FBG and obesity. This study documented the profile of NEOs and their metabolites in the blood samples from the normal and obesity cohorts in South China for the first time.