The impact of serum 25-hydroxyvitamin D, calcium, and parathyroid hormone levels on the risk of coronary artery disease in patients with diabetes: a Mendelian randomization study

Differential seasonal performance of C3-epi-D3 level and proportion on multiple metabolic disorders in patients with type 2 diabetes mellitus

BACKGROUND AND AIM

Recent Mendelian randomization and meta analysis suggest a controversial causality between C3-epimer of 25 hydroxyvitamin D3 (C3-epi-D3) and type 2 diabetes mellitus (T2DM). The clinical evidence regarding the impact of C3-epi-D3 on the progression of T2DM is currently insufficient. This study aims to investigate whether C3-epi-D3 has any effect on metabolic disorders of T2DM patients.

METHODS

A total of 1222 patients with T2DM were prospectively enrolled in this study and followed up every 1 to 2 months for 3 to 6 months. Kidney biomarkers, lipids, electrolytes, and 25 hydroxyvitamin D (25-OHD) metabolites were measured as required during follow-up, to investigate the association of C3-epi-D3 levels and %C3-epi-D3 with metabolic disorders, including dyslipidemia, chronic kidney disease (CKD), and calcium-phosphorus metabolic disorder.

RESULTS

Among these T2DM patients, there were age and seasonal differences in C3-epi-D3 levels (χ2 = 10.419 and 19.609, P = 0.034 and < 0.001), but only seasonal difference in %C3-epi-D3 (χ2 = 79.299, P < 0.001). C3-epi-D3 levels showed an evident correlation with calcium-phosphorus product during autumn and winter (ρ = - 0.336 and - 0.304, both P < 0.001), and was confirmed as an independent factor on calcium-phosphorus metabolic disorder during autumn and winter by subsequent partial correlation analysis (rpartial = - 0.300 and - 0.319, both P < 0.001). Both C3-epi-D3 levels and %C3-epi-D3 showed evident correlation with the severity of chronic kidney disease (CKD) in summer (ρ = 0.344 and 0.445, both P < 0.001). But subsequent multinomial logistic regression confirmed that only %C3-epi-D3 independently associated with moderate CKD severity in summer (OR = 1.348, P < 0.001), as well as serious CKD severity in spring, summer, and autumn (OR = 1.324, 1.342, and 1.698, all P < 0.001). Additionally, no evident correlation was observed between C3-epi-D3 and dyslipidemia.

CONCLUSION

Our study releases a seasonally differential impact of C3-epi-D3 levels and proportions on metabolic disorders of T2DM patients, considering to be potentially related to their pathogenesis of different metabolic disorders. The independent association between %C3-epi-D3 and CKD suggests a potential pathological relevance involving C3-epi-D3 itself.

Unraveling the role of gut microbiota and immune cells in thyroid cancer and tumor drug resistance

The gut microbiota (GM) and immune cells (IC) are increasingly recognized as key players in cancer development and progression. This study aimed to explore the potential mediating role of IC in the causal relationship between GM and thyroid cancer (TC) using Mendelian randomization (MR) analysis. Data from genome-wide association studies (GWAS) encompassing 473 GM species, 731 IC types, and TC were utilized. MR analysis identified nine GM species with significant causal relationships to TC, mediated by 10 IC phenotypes such as "Switched Memory AC," "IgD-CD38dim AC," and "EM DN (CD4-CD8-) AC." These findings suggest a complex interplay where specific IC mediate the effects of GM on TC risk. Sensitivity analyses confirmed the robustness of these results, with no evidence of horizontal pleiotropy. This study highlights potential mechanisms linking GM and IC to TC, offering insights that could inform GM-based immunotherapeutic strategies and IC-targeted interventions. However, further experimental research is needed to validate these causal pathways and better understand the underlying biological mechanisms.

Vitamin D and human health: evidence from Mendelian randomization studies

We summarized the current evidence on vitamin D and major health outcomes from Mendelian randomization (MR) studies. PubMed and Embase were searched for original MR studies on vitamin D in relation to any health outcome from inception to September 1, 2022. Nonlinear MR findings were excluded due to concerns about the validity of the statistical methods used. A meta-analysis was preformed to synthesize study-specific estimates after excluding overlapping samples, where applicable. The methodological quality of the included studies was evaluated according to the STROBE-MR checklist. A total of 133 MR publications were eligible for inclusion in the analyses. The causal association between vitamin D status and 275 individual outcomes was examined. Linear MR analyses showed genetically high 25-hydroxyvitamin D (25(OH)D) concentrations were associated with reduced risk of multiple sclerosis incidence and relapse, non-infectious uveitis and scleritis, psoriasis, femur fracture, leg fracture, amyotrophic lateral sclerosis, anorexia nervosa, delirium, heart failure, ovarian cancer, non-alcoholic fatty liver disease, dyslipidemia, and bacterial pneumonia, but increased risk of Behçet's disease, Graves' disease, kidney stone disease, fracture of radium/ulna, basal cell carcinoma, and overall cataracts. Stratified analyses showed that the inverse association between genetically predisposed 25(OH)D concentrations and multiple sclerosis risk was significant and consistent regardless of the genetic instruments GIs selected. However, the associations with most of the other outcomes were only pronounced when using genetic variants not limited to those in the vitamin D pathway as GIs. The methodological quality of the included MR studies was substantially heterogeneous. Current evidence from linear MR studies strongly supports a causal role of vitamin D in the development of multiple sclerosis. Suggestive support for a number of other health conditions could help prioritize conditions where vitamin D may be beneficial or harmful.