Inflammation Mediates the Associations Between Selenium Status and Glucose Metabolism in Chinese Females Over 45 Years Old: a National Cross-Sectional Study.

Abstract

Selenium (Se) status has been reported to be associated with the risk of impaired glucose metabolism, Yet the relationship remains inconclusive, and the potential mechanisms are unclear. The present study aimed to examine the associations of selenium biomarkers with type 2 diabetes (T2D) risk and glucose metabolism among females over 45 years and to explore the mediation effects of inflammation and oxidative stress. The cross-sectional study was conducted based on China Adult Chronic Disease and Nutrition Surveillance (2015-2017), including 1,430 participants. Plasma concentrations of selenium biomarkers [Se, selenoprotein P (SeP), glutathione peroxidase 3 (GPx3)] and glucose metabolism indicators [fasting blood glucose (FBG), fasting plasma insulin (FPI), glycated hemoglobin (HbA1c), homeostasis model assessment of insulin resistance (HOMA-IR)] were measured. Representative inflammatory and oxidative stress indicators were selected, and inflammatory score and oxy-score were further calculated to integrate the effects of single indicators. A high level of SeP was associated with a higher risk of T2D (OR = 1.48, 95%CI: 1.25-1.76, P-trend < 0.05), and with higher FBG, FPI, HbA1c and HOMA-IR (P < 0.05). Plasma Se was positively associated with FBG, FPI and HOMA-IR (P < 0.05). GPx3 only has a positive association with FBG (P < 0.05). Inflammatory score and interleukin-6 (IL-6) may partially mediate the associations between selenium biomarkers and glucose metabolism (P-mediation < 0.05). Excessive Se exposure is associated with an elevated risk of glucose metabolism abnormality, especially while SeP was used to evaluate the selenium status. Inflammation was found to partially explain the above associations, indicating further longitudinal research is needed.