Association between Serum Selenium Level and the Presence of Diabetes Mellitus: A Meta-Analysis of Observational Studies

Abstract

Background Epidemiological studies have suggested an association between selenium (Se) and diabetes mellitus (DM). However, different studies have reported conflicting results. Therefore, we performed a comprehensive meta-analysis to clarify the impact of Se on DM. Methods We searched the PubMed database for studies on the association between Se and DM from inception to June 2018. Results Twenty articles evaluating 47,930 participants were included in the analysis. The meta-analysis found that high levels of Se were significantly associated with the presence of DM (pooled odds ratios [ORs], 1.88; 95% confidence interval [CI], 1.44 to 2.45). However, significant heterogeneity was found ( I 2 =82%). Subgroup analyses were performed based on the Se measurement methods used in each study. A significant association was found between high Se levels and the presence of DM in the studies that used blood (OR, 2.17; 95% CI, 1.60 to 2.93; I 2 =77%), diet (OR, 1.61; 95% CI, 1.10 to 2.36; I 2 =0%), and urine (OR, 1.49; 95% CI, 1.02 to 2.17; I 2 =0%) as samples to estimate Se levels, but not in studies on nails (OR, 1.24; 95% CI, 0.52 to 2.98; I 2 =91%). Because of significant heterogeneity in the studies with blood, we conducted a sensitivity analysis and tested the publication bias. The results were consistent after adjustment based on the sensitivity analysis as well as the trim and fill analysis for publication bias. Conclusion This meta-analysis demonstrates that high levels of Se are associated with the presence of DM. Further prospective and randomized controlled trials are warranted to elucidate the link better.

Selenium and Health: An Update on the Situation in the Middle East and North Africa

“…Significant association was shown among studies that used blood, diet, and urine as specimens for Se level detection but not in studies that used nails as a sample for Se measurement. Sensitivity analysis was conducted in addition to the trim and fill analysis to account for the heterogeneity and the publication bias, yet the results were consistent upon all adjustments [18]. Another non-linear dose–response analysis confirmed that both levels below and above the physiological range are potential risk factors for diabetes which is consistent with other review articles that suggested a U-shaped relationship between Se and diabetes.…”

“…Se depending on its status has been reported to play crucial roles in normal physiology or contribute the pathophysiology of various diseases. Se has antioxidant and anti-inflammatory actions and therefore various studies have assessed the impact of Se status on conditions characterized by inflammation and oxidative stress including, neurodegenerative diseases, diabetes, cancer, and cardiovascular disorders [18].…”

“…The relationship between Se and diabetes was investigated in multiple studies with contradicting results [18]. Those studies were conducted initially following the assumption that Se is likely to exert protective effects against diabetes due to its antioxidant actions.…”

“…Se was also found to act as an insulin mimetic when in the form of selenite. Moreover, several in vitro and in vivo studies have suggested that Se plays an important role in the regulation of glucose homeostasis [18,24]. Human studies have also investigated the impact of Se on diabetes yet with conflicting conclusions.…”

Effectiveness and safety of selenium supplementation for type 2 diabetes mellitus in adults: a systematic review of randomised controlled trials

“…As a chronic hyperglycaemia can cause a substantial increase of reactive oxygen species (ROS) and oxidative stress, leading to diabetes‐related complications and a decreased Se level , it was hypothesised that, in patients diagnosed with T2DM, Se supplementation may be beneficial. However, a number of studies indicate that it may act adversely on glucose homeostasis and insulin sensitivity and even increase the risk of T2DM . This can be partially explained by the impact of Se on selenoproteins and insulin signalling .…”