Yesica Tatiana Castaño-Gallego

Background and Aims: Numerous clinical and observational studies have examined the role of vitamin D in glycemic control and metabolic regulation among diabetic patients, but findings remain inconsistent. This meta-analysis aimed to assess the effects of vitamin D supplementation on glycosylated hemoglobin (HbA1c%), HOMA-IR, HOMA-β, LDL cholesterol, total cholesterol, triglycerides, fasting insulin, fasting plasma glucose, C-reactive protein, and the likelihood of reversion to normoglycemia in prediabetic individuals. Methods: A comprehensive search of multiple databases was performed using keywords including “diabetes mellitus,” “type 2 diabetes,” “vitamin D supplementation,” and “VD supplementation.” Twenty studies met the inclusion criteria. Results: Vitamin D supplementation was associated with significant improvements across several parameters, including HOMA-β (SMD = 0.71; 95% CI: 0.63–0.80; p < 0.00001), HDL cholesterol (SMD = 0.07; 95% CI: 0.05–0.09; p < 0.00001), and others (SMD = −0.40; 95% CI: −0.45 to −0.34; p < 0.00001). Conclusions: Vitamin D supplementation appears to provide beneficial effects on glycemic, lipid, and inflammatory markers in patients with diabetes and prediabetes. Specifically, supplementation significantly reduced HbA1c%, HOMA-IR, LDL cholesterol, total cholesterol, triglycerides, fasting insulin, fasting glucose, and C-reactive protein while increasing the rate of normoglycemia among prediabetic individuals. Further research is needed to strengthen the evidence base regarding vitamin D’s role in diabetes management.

Background: The internal jugular vein (IJV) is a vascular structure that is responsible for the venous drainage of both the head and neck and is commonly found posterior to the internal carotid artery and adjacent to cervical lymph nodes or nerve structures such as the glossopharyngeal and accessory nerves. As a vagal nerve, it is an important reference point for surgical access in neck interventions and dissections. Methods: The databases Medline, Scopus, Web of Science, Google Scholar, CINAHL, and LILACS were searched until August 2024. Methodological quality was evaluated with an assurance tool for anatomical studies (AQUA). Pooled prevalence was estimated using a random effects model. Results: A total of 10 studies met the established selection criteria in this meta-analysis study. The prevalence of variants of the IJV was 3.36% (CI: 2.81–6.96%), with a heterogeneity of 94.46%. Regarding the subgroup analysis, no study presents statistically significant differences in the studies analyzed for this review. Conclusions: Knowing the IJV variants in detail will make early diagnosis useful, especially in surgeries in the neck region and in classic surgeries such as thyroidectomies and tracheostomies, among others. It will be important to know the position of the IJV.