Table 2.

Summary of evidence showing an association between elevated selenium levels and increased risk of type 2 diabetes mellitus

Ref.	Type of study	Number of participants	Evidence for T2DM risk
Vinceti et al[35], 2021	Dose-response meta-analysis	-	Non-linear dose-response association. Dramatically increase from 80 μg of daily Se intake and above
Wang et al[36], 2016	Dose-response meta-analysis	-	Non-linear dose-response association with T2DM at low and high Se concentrations
Duntas and Benvenga[37], 2015; Rocourt and Cheng[22], 2013	Reviews	-	U-shaped risk response. An excess of Se promotes hyperinsulinemia, hyperglycemia and hyperlipidemia
Rayman and Stranges[38], 2013	Review	-	Increased selenoprotein levels in T2DM patients were reduced by the characteristic inflammatory response of T2DM
Wang et al[39], 2017	Cross-sectional study	2420 participants	Negative associations were found between Se dose and insulin resistance
Wongdokmai et al[40], 2021	Cross-sectional study	655 men	Abnormal metabolism in adipocytes by excessive release of fatty acids and/or hormones
Vinceti et al[41], 2021	Prospective study	24325 participants	High Se intake increased the risk of hospitalization for T2DM
Galan-Chilet et al[42], 2017	Cross-sectional study	1452 participants	Positive association between plasma Se with prevalent and incident diabetes
Hoque and Shi[43], 2022	Cross-sectional study	18932 participants	Positively associated with diabetes but inversely associated with all-cause mortality
Faghihi et al[44], 2014	3 mo	60 T2DM patients	Se supplementation in T2DM patients with deficient Se levels resulted in adverse effects on blood glucose homeostasis

Se: Selenium; T2DM: Type 2 diabetes mellitus.