Oxidative DNA damage mediates the association between urinary metals and prevalence of type 2 diabetes mellitus in Chinese adults.

Previous publications have indicated that some metals are associated with an increased prevalence of type 2 diabetes mellitus (T2DM); however, the mechanisms remain largely unknown. This study aimed to quantify the associations of oxidative DNA damage with urinary metals and prevalence of T2DM among the general population, and further to assess the role of oxidative DNA damage in mediating the association of urinary metals with prevalence of T2DM. Diagnoses of T2DM were performed clinically or by measuring fasting levels of plasma glucose ≥7.0mmol/L. Concentrations of urinary metals and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in 2127 participants were measured using inductively coupled plasma-mass spectrometry and high-performance liquid chromatography. Relationships among urinary metals, 8-OHdG (a biomarker for oxidative DNA damage), and prevalence of T2DM were analyzed using mediation analysis. After adjusting for covariates, we found that the log-transformed levels of urinary copper, arsenic, selenium, molybdenum, and antimony were positively associated with prevalence of T2DM. Urinary 8-OHdG was not only positively correlated with copper, arsenic, selenium, and antimony in an upwardly trending, dose-responsive manner but was also positively associated with prevalence of T2DM (odds ratio (OR): 1.95; 95% CI: 1.17-3.24). Mediation analysis estimated that urinary 8-OHdG mediated 13.22% and 8.84% of associations between prevalence of T2DM and concentrations of urinary arsenic and antimony, respectively (all P value<0.05). Our findings suggested that urinary arsenic and antimony concentrations were associated with an increased prevalence of T2DM by a mechanism partly involving oxidative DNA damage.
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