Navigating Complexities: Vitamin D, Skin Pigmentation, and Race.

Vitamin D plays a critical role in many physiological functions, including calcium metabolism and musculoskeletal health. This commentary aims to explore the intricate relationships among skin complexion, race, and 25-hydroxyvitamin D (25[OH]D) levels, focusing on challenges the Endocrine Society encountered during clinical practice guideline development. Given that increased melanin content reduces 25(OH)D production in the skin in response to UV light, the guideline development panel addressed the potential role for 25(OH)D screening in individuals with dark skin complexion.

A Systematic Review Supporting the Endocrine Society Clinical Practice Guidelines on Vitamin D.

Context: Low vitamin D status is common and is associated with various common medical conditions.

Objective: To support the development of the Endocrine Society's Clinical Practice Guideline on Vitamin D for the Prevention of Disease.

Methods: We searched multiple databases for studies that addressed 14 clinical questions prioritized by the guideline panel.

Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline.

Background: Numerous studies demonstrate associations between serum concentrations of 25-hydroxyvitamin D (25[OH]D) and a variety of common disorders, including musculoskeletal, metabolic, cardiovascular, malignant, autoimmune, and infectious diseases. Although a causal link between serum 25(OH)D concentrations and many disorders has not been clearly established, these associations have led to widespread supplementation with vitamin D and increased laboratory testing for 25(OH)D in the general population. The benefit-risk ratio of this increase in vitamin D use is not clear, and the optimal vitamin D intake and the role of testing for 25(OH)D for disease prevention remain uncertain.

Racial differences in measures of glycemia in the Vitamin D and Type 2 Diabetes (D2d) Study: a secondary analysis of a randomized trial.

Introduction: Understanding how race may influence the association between A1c and glycemia can improve diabetes screening. We sought to determine whether, for a given A1c level, glucose levels during an oral glucose tolerance test (OGTT) differed by race.

Research Design And Methods: From data collected at 22 US clinical sites, we conducted a cross-sectional study of concurrently measured A1c and OGTT and observational longitudinal follow-up of the subset with high-risk pre-diabetes.

Effect of vitamin D on regression to normal glucose regulation and individual glycemic measures: A secondary analysis among participants adherent to the trial protocol in the randomized clinical trial vitamin D and type 2 diabetes (D2d) study.

Aims: To examine the effect of vitamin D on regression to normal glucose regulation (NGR) and individual glycemic measures in the D2d study.

Methods: In per-protocol analyses, we examined time to new-onset diabetes; time to new-onset NGR defined as first occurrence of: 2-or-3 glycemic criteria in the normal range (NGR-1) or fasting plasma glucose (FPG) and 2-hour post-load-glucose (2hPG) in the normal range (NGR-2); proportion meeting NGR at the last study visit; and change in FPG, 2hPG, and HbA1c.

Results: Among 2423 participants, hazard ratio [HR] for diabetes was 0.

New-Onset Diabetes After COVID-19.

There is evidence suggesting that infection with SARS-CoV-2 can lead to several long-term sequelae including diabetes. This mini-review examines the rapidly evolving and conflicting literature on new-onset diabetes after COVID-19, which we term NODAC. We searched PubMed, MEDLINE, and medRxiv from inception until December 1, 2022, using Medical Subject Headings (MeSH) terms and free text words including "COVID-19," "SARS-CoV-2," "diabetes," "hyperglycemia," "insulin resistance," and "pancreatic β-cell.

Indices of hepatic steatosis and fibrosis in prediabetes and association with diabetes development in the vitamin D and type 2 diabetes study.

Aims: Non-alcoholic fatty liver disease (NAFLD) is a common comorbidity that leads to poor outcomes in people at high risk for development of type 2 diabetes (T2D). Vitamin D is a possible mediator. In the vitamin D and type 2 diabetes study (D2d), we investigated the relationship of baseline indices of NAFLD with incident T2D and whether the effect of vitamin D on diabetes was modified by NAFLD.

Effect of intratrial mean 25(OH)D concentration on diabetes risk, by race and weight: an ancillary analysis in the D2d study.

Background: Higher serum 25-hydroxyvitamin D [25(OH)D] is associated with lower type 2 diabetes risk. 25(OH)D varies due to skin pigmentation and weight.

Objectives: This analysis aims to determine whether the effect of vitamin D differs among people of color and those with overweight/obesity (who have higher diabetes risk) compared with individuals who are White or have normal weight.

Vitamin D and Risk for Type 2 Diabetes in People With Prediabetes : A Systematic Review and Meta-analysis of Individual Participant Data From 3 Randomized Clinical Trials.

Background: The role of vitamin D in people who are at risk for type 2 diabetes remains unclear.

Purpose: To evaluate whether administration of vitamin D decreases risk for diabetes among people with prediabetes.

Data Sources: PubMed, Embase, and ClinicalTrials.

Effect of vitamin D supplementation on circulating fibroblast growth factor-23 concentration in adults with prediabetes.

Background: Recent meta-analyses report that vitamin D supplementation increases blood fibroblast growth factor-23 (FGF23) level.

Objectives: To determine the effect of 4000 IU/day of vitamin D for 12 months on circulating FGF23 levels. We also examined the association of the achieved 25-hydroxyvitamin D level [25(OH)D] with the FGF23 level at 12 months and with 12-month changes in FGF23.

The effect of vitamin D supplementation on cardiovascular risk in patients with prediabetes: A secondary analysis of the D2d study.

Aims: Low blood 25(OH)D level is associated with increased cardiovascular disease (CVD) risk. Additionally, individuals with prediabetes are at higher risk for CVD than individuals with normoglycemia. We investigated the effects of vitamin D supplementation on CVD outcomes in the vitamin D and type 2 diabetes (D2d) study, a large trial among adults with prediabetes.

Safety and tolerability of high-dose daily vitamin D supplementation in the vitamin D and type 2 diabetes (D2d) study-a randomized trial in persons with prediabetes.

Background/objectives: Routine use of vitamin D supplements has increased substantially in the United States. However, the safety and tolerability of long-term use of high-dose vitamin D are not known. We assessed the safety and tolerability of high-dose, daily vitamin D in the vitamin D and type 2 diabetes (D2d) study.

Effects of Vitamin D Supplementation on Insulin Sensitivity and Secretion in Prediabetes.

Context: Vitamin D regulates glucose homeostasis pathways, but effects of vitamin D supplementation on β-cell function remain unclear.

Objective: To investigate the effects of vitamin D3 supplementation on insulin sensitivity and β-cell function.

Methods: This is a prespecified secondary analysis of the Vitamin D and Type 2 Diabetes study.

Randomized trial of a novel lifestyle intervention compared with the Diabetes Prevention Program for weight loss in adult dependents of military service members.

Background: Lifestyle interventions are the first-line treatment for obesity, but participant weight loss is typically low.

Objectives: We evaluated the efficacy of an alternative lifestyle intervention [Healthy Weight for Living (HWL)] compared with a modified Diabetes Prevention Program (m-DPP). HWL was based on a revised health behavior change model emphasizing hunger management and the development of healthy food preferences.

Effect of Vitamin D Supplementation on Kidney Function in Adults with Prediabetes: A Secondary Analysis of a Randomized Trial.

Background And Objectives: Low serum 25-hydroxyvitamin D (25[OH]D) concentration has been associated with higher levels of proteinuria and lower levels of eGFR in observational studies. In the Vitamin D and Type 2 Diabetes (D2d) study, we investigated the effect of vitamin D supplementation on kidney outcomes in a population with prediabetes.

Design, Setting, Participants, & Measurements: Overweight/obese adults with high risk for type 2 diabetes (defined by meeting two of three glycemic criteria for prediabetes) were randomized to vitamin D 4000 IU per day versus placebo.

Vitamin D Supplementation for Prevention of Cancer: The D2d Cancer Outcomes (D2dCA) Ancillary Study.

Context: Observational studies suggest that low vitamin D status may be a risk factor for cancer.

Objective: In a population with prediabetes and overweight/obesity that is at higher risk of cancer than the general population, we sought to determine if vitamin D supplementation lowers the risk of cancer and precancers.

Methods: The Vitamin D and type 2 diabetes (D2d) cancer outcomes study (D2dCA) is an ancillary study to the D2d study, which was conducted at 22 academic medical centers in the United States.

Intratrial Exposure to Vitamin D and New-Onset Diabetes Among Adults With Prediabetes: A Secondary Analysis From the Vitamin D and Type 2 Diabetes (D2d) Study.

Objective: Postrandomization biases may influence the estimate of efficacy of supplemental vitamin D in diabetes prevention trials. In the Vitamin D and Type 2 Diabetes (D2d) study, repeated measures of serum 25-hydroxyvitamin D [25(OH)D] level provided an opportunity to test whether intratrial vitamin D exposure affected diabetes risk and whether the effect was modified by trial assignment (vitamin D vs. placebo).

Vitamin D Supplementation for Prevention of Type 2 Diabetes Mellitus: To D or Not to D?

Context: Over the last decade, vitamin D has emerged as a risk determinant for type 2 diabetes and vitamin D supplementation has been hypothesized as a potential intervention to lower diabetes risk. Recently, several trials have reported on the effect of vitamin D supplementation on diabetes prevention in people with prediabetes.

Evidence Acquisition: A comprehensive literature review was performed using PubMed, Embase, and ClinicalTrials.