High serum selenium levels are associated with impaired fasting glucose and elevated fasting serum glucose in Linyi, China

Associations of metals and metal mixtures with glucose homeostasis: A combined bibliometric and epidemiological study

This study employs a combination of bibliometric and epidemiological methodologies to investigate the relationship between metal exposure and glucose homeostasis. The bibliometric analysis quantitatively assessed this field, focusing on study design, predominant metals, analytical techniques, and citation trends. Furthermore, we analyzed cross-sectional data from Beijing, examining the associations between 14 blood metals and 6 glucose homeostasis markers using generalized linear models (GLM). Key metals were identified using LASSO-PIPs criteria, and Bayesian kernel machine regression (BKMR) was applied to assess metal mixtures, introducing an "Overall Positive/Negative Effect" concept for deeper analysis. Our findings reveal an increasing research interest, particularly in selenium, zinc, cadmium, lead, and manganese. Urine (27.6%), serum (19.0%), and whole blood (19.0%) were the primary sample types, with cross-sectional studies (49.5%) as the dominant design. Epidemiologically, significant associations were found between 9 metals-cobalt, copper, lithium, manganese, nickel, lead, selenium, vanadium, zinc-and glucose homeostasis. Notably, positive-metal mixtures exhibited a significant overall positive effect on insulin levels, and notable interactions involving nickel were identified. These finding not only map the knowledge landscape of research in this domain but also introduces a novel perspective on the analysis strategies for metal mixtures.

Impact of age, sex, and thyroid autoimmunity on the association between selenium intake and type 2 diabetes mellitus

BACKGROUND

The association between dietary selenium(Se) intake and type 2 diabetes mellitus (T2DM) remains controversial. The present study aimed to investigate this association using data from the National Health and Nutrition Examination Survey (NHANES) database for the years 2007-2012.

METHODS

Three thousand seventy three individuals aged 20 years and above were eligible for inclusion in this cross-sectional study. The average age of the participants was 50.74 years and the proportions of males and females were nearly equal (49.12% vs. 50.88%). The odds ratios (OR) of the association between dietary Se intake (log2-transformed) and T2DM were examined through the multivariate logistic regression model. Subgroup analyses were conducted based on age, sex, and thyroid autoimmunity to assess the potential impact of these variables on the relationship. Fitted smoothing curves and threshold effect analysis were conducted to describe the nonlinear relationship.

RESULTS

In the fully adjusted model, a significant positive association between Se intake and T2DM was observed (OR = 1.49, 95% CI: 1.16, 1.90, p = 0.0017). After stratifying the data by age, sex, and thyroid autoimmunity, a significant positive association between Se intake and T2DM was observed in individuals under 65 years of age, males, and those with negative thyroid autoimmunity. A two-segment linear regression model was analyzed for sex stratification, revealing a threshold effect in males with an inflection point of 90.51 μg, and an inverted U-shaped relationship in females with an inflection point of 109.90 μg, respectively.

CONCLUSIONS

The present study found a positive relationship between Se intake and the prevalence of T2DM. This association is particularly significant in younger individuals, males, and those with negative thyroid autoimmunity. Our results should be validated in future large prospective studies in different populations.

Identification of the regulatory network and potential markers for type 2 diabetes mellitus related to internal exposure to metals in Chinese adults

People intake metals from their environment. This study investigated type 2 diabetes mellitus (T2DM) related to internal exposure to metals and attempted to identify possible biomarkers. A total of 734 Chinese adults were enrolled, and urinary levels of ten metals were measured. Multinomial logistic regression model was used to assess the association between metals and impaired fasting glucose (IFG) and T2DM. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein-protein interaction were used to explore the pathogenesis of T2DM related to metals. After adjustment, lead (Pb) was positively associated with IFG (odds ratio [OR] 1.31, 95% confidence interval [CI] 1.06-1.61) and T2DM (OR 1.41, 95% CI 1.01-1.98), but cobalt was negatively associated with IFG (OR 0.57, 95% CI 0.34-0.95). Transcriptome analysis showed 69 target genes involved in the Pb-target network of T2DM. GO enrichment indicated that the target genes are enriched mainly in the biological process category. KEGG enrichment indicated that Pb exposure leads to non-alcoholic fatty liver disease, lipid and atherosclerosis, and insulin resistance. Moreover, there is alteration of four key pathways, and six algorithms were used to identify 12 possible genes in T2DM related to Pb. SOD2 and ICAM1 show strong similarity in expression, suggesting a functional correlation between these key genes. This study reveals that SOD2 and ICAM1 may be potential targets of Pb exposure-induced T2DM and provides novel insight into the biological effects and underlying mechanism of T2DM related to internal exposure to metals in the Chinese population.

Association between plasma selenium and risk of ischemic stroke: A community-based, nested, and case-control study

Background

The prospective association between plasma Se and stroke risk remains inconclusive. The relationship between Se and ischemic stroke among a low circulating Se status population deserves more attention, especially for Chinese people who were a high-risk group for Se deficiency.

Objective

The relationship between plasma Se concentration and ischemic stroke risk in a large-scale Chinese community-based population and any potential effect modifiers were investigated.

Methods

A nested, case-control study, using data from the “China H-type Hypertension Registry Study” were conducted. A total of 1,904 first ischemic stroke cases and 1,904 controls matched for age, sex, and village were included in this study. The association between plasma Se and first ischemic stroke was evaluated by conditional logistic regression analyses.

Results

The median value of plasma Se was 65.8 μg/L among total participants. Overall, a significant inverse relationship between plasma Se and first ischemic stroke risk was found (per SD increment; adjusted OR: 0.87; 95% CI: 0.80 and 0.95). Accordingly, a significantly lower risk of first ischemic stroke was found in participants in quartile 3 (65.8−<77.8 μg/L) (adjusted OR: 0.78; 95% CI: 0.63 and 0.96) and quartile 4 (≥77.8 μg/L) (adjusted OR: 0.76; 95% CI: 0.59 and 0.96), compared with those in quartile 1 (<56.0 μg/L). Furthermore, a significantly lower ischemic stroke risk was found in those with lower low-density lipoprotein cholesterol (LDL-C) levels (<3.4 vs. ≥3.4 mmol/L; P for interaction = 0.015) or those with lower homocysteine levels (<12.1 (median) vs. ≥12.1 μmol/L; P for interaction = 0.027) at baseline.

Conclusion

Plasma Se was significantly inversely associated with the risk of first ischemic stroke among a large-scale Chinese community-based population (most adults with hypertension and elevated total homocysteine), especially among those with lower LDL-C and lower homocysteine levels.

Higher selenium was associated with higher risk of diabetes: Consistent evidence from longitudinal and cross-sectional studies based on nail and serum selenium measures

Although the association between selenium (Se) and diabetes has been well-discussed in recent years, few studies have focused on the effects of long-term natural Se exposure and rarely concerned the effects of different Se biomarkers. To address this question, we carried out a 7-year longitudinal study on older adults aged over 65 and another cross-sectional study on middle-aged and older adults aged 40 and above from Chinese soil Se-deplete and Se-optimum areas. Cox proportional hazard models were used to evaluate the associations between nail Se levels and incidence risk of diabetes. Unconditional logistic regression models and analysis of variance models were used to examine the associations between serum Se levels and the prevalence risk of diabetes. The nail and serum Se levels were 0.47 ± 0.20 μg/g and 111.09 ± 55.01 μg/L for the two study populations, respectively. For both of the independent studies, higher Se levels were observed to be associated with a higher risk of diabetes and prediabetes. Compared with the Second nail Se quartile (Q2), the adjusted hazard ratios (HRs) and 95 % confidence intervals (95 % CIs) of diabetes for Q1, Q3 and Q4 were 1.24(0.70, 2.21), 1.53(0.98, 2.39) and 1.31(0.76, 2.26), respectively, and the adjusted HRs (95 % CIs) of prediabetes were 1.47(0.77, 2.81), 1.38(0.83, 2.30), and 1.97(1.13, 3.44), respectively. Compared with the first serum Se quintile (Q1), the adjusted odds ratios (ORs) and 95 % CIs of diabetes for higher quintiles were 1.12(0.75, 1.66), 1.05(0.71, 1.57), 1.09(0.73, 1.62) and 1.51(1.02, 2.19), and the adjusted ORs (95 % CIs) of prediabetes were 1.27(0.77, 2.09), 1.70(1.05, 2.74), 1.94(1.21, 3.11) and 1.67(1.03, 2.71). Our findings consistently suggest that higher Se status is associated with a higher risk of diabetes in adults.

Sex-Specific Association between Fasting Plasma Glucose and Serum Selenium Levels in Adults from Southern Mexico

Selenium (Se) is an essential trace element that by its antioxidant properties has been studied to elucidate its participation in the development of obesity and type 2 diabetes. We evaluated the association between cardiometabolic traits and serum Se levels in a sample of adults from southern Mexico. In 96 nondiabetic individuals, anthropometric data and clinical biochemistry measurements were analyzed. Serum total Se levels were measured with inductively coupled plasma mass spectrometry (ICP-MS). Serum Se level in the whole sample was 10.309 ± 3.031 μg mL-1 and no difference between the women and men was observed (p = 0.09). Additionally, fasting plasma glucose (FPG) was significantly associated with serum Se level (β = -0.07 ± 0.03, p = 0.02, analysis adjusted for age, sex and BMI). Furthermore, sex shows significant interaction with FPG on the serum Se levels (p = 0.01). A follow-up analysis revealed the particular association between FPG and Se levels in women (β = -0.10 ± 0.04, p = 0.01). In conclusion, our data evidenced a women-specific association between FPG and serum Se levels in a sample of adults from southern Mexico.

Novel Strategies for Assessing Associations Between Selenium Biomarkers and Cardiometabolic Risk Factors: Concentration, Visit-to-Visit Variability, or Individual Mean? Evidence From a Repeated-Measures Study of Older Adults With High Selenium

Background and Aims

Previous studies have focused only on the cardiometabolic effects of selenium concentrations. We explored whether selenium levels and their visit-to-visit variability (VVV) and individual mean (IM) are independently associated with cardiometabolic risk factors.

Methods

A three-wave repeated-measures study of older adults with high selenium (n = 201) was conducted in Beijing from 2016 to 2018. Whole blood selenium and urinary selenium concentrations were measured. VVV and IM were used to profile the homeostasis of the selenium biomarkers. Four indicators, namely standard deviation, coefficient of variation, average real variability, and variability independent of the mean, were employed to characterize VVV. We considered 13 cardiometabolic factors: four lipid profile indicators, three blood pressure indices, glucose, uric acid, waistline, hipline, waist-hip ratio, and sex-specific metabolic syndrome score. Linear mixed-effects regression models with random intercepts for the participants were employed to explore the associations of the selenium concentrations, VVV, and IM with the cardiometabolic factors.

Results

The geometric mean whole blood and urinary selenium levels were 134.30 and 18.00 μg/L, respectively. Selenium concentrations were significantly associated with numerous cardiometabolic factors. Specifically, whole blood selenium was positively associated with total cholesterol [0.22, 95% confidence interval (CI): 0.12, 0.33], low-density lipoprotein cholesterol (LDL-C; 0.28, 95% CI: 0.13, 0.42), glucose (0.22, 95% CI: 0.10, 0.34), and uric acid (0.16, 95% CI: 0.04, 0.28). After adjustment for VVV, the IM of whole blood selenium was positively correlated with total cholesterol (0.002, 95% CI: 0.001, 0.004), triglycerides (0.007, 95% CI: 0.004, 0.011), and LDL-C (0.002, 95% CI: 0.000, 0.004). However, we did not observe any robust associations between the VVV of the selenium biomarkers and cardiometabolic risk factors after adjustment for IM.

Conclusion

Our findings suggest that selenium concentrations and their IMs are significantly associated with cardiometabolic risk factors among older adults with high selenium. Longer repeated-measures studies among the general population are required to validate our findings and elucidate the relevant underlying mechanisms.

Cross-sectional study: Relationship between serum trace elements and hypertension

BACKGROUND

A balanced intake of trace elements is beneficial for chronic diseases such as hypertension. However, the available information regarding trace elements that may be independently associated with hypertension is limited, and the relationship between this disorder and element ratios also remains unclear.

METHODS

A total of 6,754 subjects from rural China were selected, after exclusion of patients who were under 18, had incomplete data or had additional related disorders, by multi-stage simple random and cluster sampling (participation rate: 95.22 %). Subjects were divided into a hypertensive (H) and a control (C) group. Data were collected on blood pressure and 12 serum trace elements were measured by flame atomic absorption spectrometry and inductively coupled plasma-mass spectrometry. Other basic information was collated from questionnaires and biochemical indicators were measured via kits.

RESULTS

Differences in serum levels of magnesium (Mg(mg/l): H: 27.43 ± 12.72; C: 26.33 ± 12.16), iron (Fe(mg/l): H: 1.99 ± 1.24; C: 1.84 ± 1.16), copper (Cu(mg/l): H: 1.19 ± 0.37; C: 1.10 ± 0.36), boron (B(μg/l): H: 50.00 ± 25.21; C: 47.57 ± 26.25), selenium (Se(μg/l): H: 125.12 ± 32.81; C: 118.80 ± 29.72) and chromium (Cr(μg/l): H: 8.77 ± 10.12; C: 10.12 ± 10.72) between the hypertensive and control groups were found. There were no differences in serum contents of calcium (Ca(mg/l): H: 112.43 ± 58.25; C: 111.00 ± 59.49), zinc (Zn(mg/l): H: 1.50 ± 1.97; C: 1.44 ± 1.88), arsenic (As(μg/l): H: 4.17 ± 3.94; C: 4.10 ± 4.00), manganese (Mn(μg/l): H: 4.15 ± 4.03; C: 4.07 ± 4.05), cadmium (Cd(μg/l): H: 1.14 ± 1.11; C: 1.18 ± 1.12) or lead (Pb(μg/l): H: 4.22 ± 8.90; C: 4.26 ± 10.25). The serum Cr and Cd concentrations of hypertensive men were lower than that of male controls while Mg, Cu, Ca and Se concentrations in male controls were lower. Further differences were apparent and Fe, B, Se, Mg and Cu all showed higher levels in hypertensive females whereas Cr concentrations were higher in female controls. Serum Zn and B levels showed age-related variations among hypertensive patients and concentrations of serum Cu, Zn, Se and B showed age-related variations among control subjects. For hypertensive patients, the odds ratio (OR) and 95 % confidence interval (CI) for the association of serum Cu, Se and Cr levels with hypertension were Cu: 1.36 (1.12-1.66); Se: 1.03 (1.01-1.05); Cr: 0.89 (0.83-0.96). Moreover, when the participants in the grouping with the highest copper/zinc (Cu/Zn) and magnesium/manganese (Mg/Mn) ratios were compared with the reference group, the OR and 95 % CI for hypertension were 1.22 (1.04-1.44) and 1.20 (1.01-1.42), respectively.

CONCLUSIONS

Levels of serum trace elements showed age- and sex-related differences in a group of rural Chinese adults with hypertension and healthy participants. Serum concentrations of Cu, Se and Cr may be independently associated with hypertension. Higher serum ratios of Cu:Zn and Mg:Mn may also be associated with hypertension. Further randomized trials are necessary to elucidate the true relationship between levels of Cu, Se, Cr, Cu:Zn, Mg:Mn and hypertension.

Genetically predicted selenium is negatively associated with serum TC, LDL-C and positively associated with HbA1C levels

BACKGROUND & AIMS

Pervious epidemiological evidence on the associations of selenium, zinc with lipid profile and glycemic indices was contradictory. The aim of this study was to investigate whether selenium and zinc were casually associated with lipid profile and glycemic indices using mendelian randomization (MR) analysis.

METHOD

A two-sample MR was used to evaluate the causal-effect estimations. Summary statistics for selenium, zinc, lipids and glycemic indices were retrieved from previous large-scale genome-wide association study (GWAS). Single nucleotide polymorphisms (SNPs) that independently and strongly associated with the selenium and zinc were selected as the instrumental variables. The casual estimates were calculated using inverse variance weighted method (IVW), with weighted median, MR-Egger, and MR-PRESSO test as sensitivity analysis, respectively.

RESULTS

In the standard IVW analysis, per SD increment in selenium was associated with an 0.077 mmol/L decrease of TC (95 %CI: -0.102,-0.052) and 0.074 mmol/L of LDL-C (95 %CI: -0.1,-0.048). Suggestive casual associations were found between selenium and insulin or HbA1c. With IVW method, per SD increase in selenium was associated with an 0.023 mmol/L increase of insulin (95 %CI: 0.001,0.045), and an 0.013 mmol/L increase of HbA1c (95 %CI: 0.003,0.023). The results were robust in the sensitivity analysis. Zinc was not casually associated with any of lipid and glycemic markers.

CONCLUSION

Our MR analysis provides evidence of the potential causal effect of Se on beneficial lipid profile, including decreased TC and LDL-C. Furthermore, suggestive casual evidence was suggested between Se and increased serum HbA1c levels. Careful consideration is required for the protective effects of Se supplementation. No casual-effect association was found between Zn and any indices of the lipid and glucose parameters.

Association of twenty-three plasma elements with fasting serum glucose among Chinese population from four areas with different pollution level

BACKGROUND

Association between fasting serum glucose (FSG) and certain mineral elements has been extensively reported. Investigation regarding multi-element exposure among subjects with different exposure level is warranted to confirm the association and further explore dose-dependent relationship.

METHODS

A total of 3488 participants were recruited from four counties of Hunan province, South China. Basic characteristics were collected by face to face interview and 23 elements in plasma were determined by inductively coupled plasma mass spectrometry. We applied fully adjusted generalized linear regression model and multivariable restricted cubic spline function to test the association and dose-response relationship of FSG with 23 elements.

RESULTS

The results indicated that FSG was positively associated with plasma78selenium level [regression coefficient (β), 0.001; 95 % confidence interval (CI), 0.001, 0.001] in a dose-dependent manner, robust to the adjustment for suspected covariates and stratification by age, gender, BMI and smoking status. A negative association was found between FSG and plasma 208lead (β, -0.004; 95 % CI, -0.016, -0.002), 52chromium (β, -0.002; 95 % CI, -0.004, -0.001) and 47titanium (β, -0.001; 95 % CI, -0.002, -0.001).

CONCLUSION

78selenium was positively while 208lead, 52chromium and 47titanium were negatively associated with FSG in the present study. However, prospective studies are needed to confirm the results.

Targeted Metabolomics Analysis Reveals that Dietary Supranutritional Selenium Regulates Sugar and Acylcarnitine Metabolism Homeostasis in Pig Liver

BACKGROUND

The association between high selenium (Se) intake and metabolic disorders such as type 2 diabetes has raised great concern, but the underlying mechanism remains unclear.

OBJECTIVE

Through targeted metabolomics analysis, we examined the liver sugar and acylcarnitine metabolism responses to supranutritional selenomethionine (SeMet) supplementation in pigs.

METHODS

Thirty-six castrated male pigs (Duroc-Landrace-Yorkshire, 62.0 ± 3.3 kg) were fed SeMet adequate (Se-A, 0.25 mg Se/kg) or SeMet supranutritional (Se-S, 2.5 mg Se/kg) diets for 60 d. The Se concentration, biochemical, gene expression, enzyme activity, and energy-targeted metabolite profiles were analyzed.

RESULTS

The Se-S group had greater fasting serum concentrations of glucose (1.9-fold), insulin (1.4-fold), and free fatty acids (FFAs,1.3-fold) relative to the Se-A group (P < 0.05). The liver total Se concentration was 4.2-fold that of the Se-A group in the Se-S group (P < 0.05), but expression of most selenoprotein genes and selenoenzyme activity did not differ between the 2 groups. Seven of 27 targeted sugar metabolites and 4 of 21 acylcarnitine metabolites significantly changed in response to high SeMet (P < 0.05). High SeMet supplementation significantly upregulated phosphoenolpyruvate carboxy kinase (PEPCK) activity by 64.4% and decreased hexokinase and succinate dehydrogenase (SDH) activity by 46.5-56.7% (P < 0.05). The relative contents of glucose, dihydroxyacetone phosphate, α-ketoglutarate, fumarate, malate, erythrose-4-phosphate, and sedoheptulose-7-phosphate in the Se-S group were 21.1-360% greater than those in the Se-A group (P < 0.05). The expression of fatty acid synthase (FASN) and the relative contents of carnitine, hexanoyl-carnitine, decanoyl-carnitine, and tetradecanoyl-carnitine in the Se-S group were 35-97% higher than those in the Se-A group (P < 0.05).

CONCLUSIONS

Dietary high SeMet-induced hyperglycemia and hyperinsulinemia were associated with suppression of sugar metabolism and elevation of lipid synthesis in pig livers. Our research provides novel insights into high SeMet intake-induced type 2 diabetes.

The Correlation between Dietary Selenium Intake and Type 2 Diabetes: A Cross-Sectional Population-Based Study on North Chinese Adults

The relationship between selenium (Se) and type 2 diabetes (T2D) remains controversial. In previous animal and cell studies, Se was found to be insulin mimic and antidiabetic, whereas recent epidemiological and interventional trials have shown an unexpected association between high Se intake and increased risk of T2D. The present study aimed to investigate the significance of dietary Se and T2D in North Chinese adults. A large sample of the population was enrolled through cluster sampling in Northern China (N=8824). Information on basic characteristics, anthropometric measures, and dietary Se intake was collected from each subject for analysis. Multivariable logistic regression was used to investigate the association between dietary Se and T2D through adjusted odds ratio (OR) and the corresponding 95% confidence interval (CI). The average nutritional Se intake was 52.43 μg/day, and the prevalence of T2D was 20.4% in the studied population. The OR for developing T2D was 1.66 (95% CI: 1.38, 1.99; P for linear trend <0.005), comparing the highest to the lowest quintile of energy-adjusted Se intake in multivariate logistic regression analysis. The mediation analysis discovered that glucose metabolism (indicated by FBG and HbA1c) mediated this association. In conclusion, our research adds further support to the role of high dietary Se in the incidence of T2D. The results also suggested that this association was mediated by glucose metabolism.

Serum and Urinary Selenium Status in Patients with the Pre-diabetes and Diabetes in Northeast China

Homeostasis imbalance of selenium (Se) in diabetes has received great attention. This study investigated serum and urinary Se levels in patients with impaired fasting glucose (IFG), impaired glucose tolerance (IGT), type 1 diabetes (T1D), and type 2 diabetes (T2D) in Northeast Chinese populations. From January 2010 to October 2011, patients with IFG (n = 12), IGT (n = 15), T1D (n = 25), T2D (n = 137), and healthy controls (n = 50) were enrolled in the First Hospital of Jilin University. Se was detected using inductively coupled plasma spectrometer. The serum Se level was dramatically lower in patients with T1D and was significantly higher in IFG subjects, and the urinary Se concentration was markedly lower in IGT and T2D groups. The serum Se levels were positively correlated with serum zinc (Zn) in both IFG and IGT groups, while urinary Se were positively associated with urinary Zn and copper (Cu) in IGT group. The serum Se levels were positively correlated with serum Cu in both T1D and T2D groups, and urinary levels of Se were positively associated with serum zinc and urinary Cu, Zn, calcium (Ca), and magnesium (Mg) and negatively correlated with serum Ca and Mg in T2D group, while the urinary levels of Se were positively correlated with urinary Zn and Mg both in peripheral neuropathy (DPN) and retinopathy (DR) groups. One month of simvastatin therapy reduced serum Se levels. These results suggest the potential role of Se in diabetes should receive attention.