Vitamin D as a Biomarker of Ill Health among the Over-50s: A Systematic Review of Cohort Studies

Hormones and Aging: An Endocrine Society Scientific Statement

Multiple changes occur across various endocrine systems as an individual ages. The understanding of the factors that cause age-related changes and how they should be managed clinically is evolving. This statement reviews the current state of research in the growth hormone, adrenal, ovarian, testicular, and thyroid axes, as well as in osteoporosis, vitamin D deficiency, type 2 diabetes, and water metabolism, with a specific focus on older individuals. Each section describes the natural history and observational data in older individuals, available therapies, clinical trial data on efficacy and safety in older individuals, key points, and scientific gaps. The goal of this statement is to inform future research that refines prevention and treatment strategies in age-associated endocrine conditions, with the goal of improving the health of older individuals.

Associations of 25-Hydroxyvitamin D Status and Supplementation with Adverse Outcomes in Geriatric Rehabilitation Inpatients: RESORT

OBJECTIVES

Geriatric rehabilitation inpatients are at a higher risk of 25-hydroxyvitamin D (25(OH)D) deficiency due to poor nutrition and low sunlight exposure. This study aimed to evaluate the prevalence of 25-hydroxyvitamin (25(OH)D) deficiency and supplementation and to investigate their association with adverse health outcomes in geriatric rehabilitation inpatients.

DESIGN

Prospective, observational and longitudinal study.

SETTING AND PARTICIPANTS

Geriatric rehabilitation inpatients admitted to geriatric rehabilitation wards at the Royal Melbourne Hospital (Melbourne, Australia) from 16th, October 2017 and discharged until 18th, March 2020 in the REStORing health of acutely unwell adulTs (RESORT) study were included.

METHODS

25(OH)D levels measured close to rehabilitation admission were classified as sufficiency (>54 nmol/L), insufficiency (26-54 nmol/L), or deficiency (<26 nmol/L). The usage of vitamin D supplementation was extracted from medication records. Outcomes included incidence of institutionalization at three-month post-discharge, in-hospital mortality and post-discharge mortality.

RESULTS

The median age of 1328 geriatric rehabilitation inpatients was 83.9 years (IQR: 78.1-88.7, 58.6% female). 25(OH)D deficiency and insufficiency were present in 8.1% and 26.4% of inpatients, respectively; 74.2% used vitamin D supplementation. 25(OH)D deficiency was associated with higher odds of institutionalization (odds ratio (OR): 1.88, 95% confidence interval (CI): 1.14-3.11), in-hospital mortality (OR: 3.30, 95% CI: 1.54-7.07) and higher risks of one-year mortality (hazard ratio (HR): 1.77, 95% CI: 1.17-2.69) compared to 25(OH)D sufficiency but not with three-month mortality. 25(OH)D insufficiency was not associated with outcomes. Patients who did not use supplementation and had 25(OH)D insufficiency or deficiency had significantly higher in-hospital mortality compared to those who used supplementation.

CONCLUSIONS

Among geriatric rehabilitation inpatients, 25(OH)D deficiency was associated with institutionalization, in-hospital mortality and one-year mortality. Attention to monitor the vitamin D status is of upmost importance during hospitalization.

The Interrelated Multifactorial Actions of Cortisol and Klotho: Potential Implications in the Pathogenesis of Parkinson's Disease

The pathogenesis of Parkinson's disease (PD) is complex, multilayered, and not fully understood, resulting in a lack of effective disease-modifying treatments for this prevalent neurodegenerative condition. Symptoms of PD are heterogenous, including motor impairment as well as non-motor symptoms such as depression, cognitive impairment, and circadian disruption. Aging and stress are important risk factors for PD, leading us to explore pathways that may either accelerate or protect against cellular aging and the detrimental effects of stress. Cortisol is a much-studied hormone that can disrupt mitochondrial function and increase oxidative stress and neuroinflammation, which are recognized as key underlying disease mechanisms in PD. The more recently discovered klotho protein, considered a general aging-suppressor, has a similarly wide range of actions but in the opposite direction to cortisol: promoting mitochondrial function while reducing oxidative stress and inflammation. Both hormones also converge on pathways of vitamin D metabolism and insulin resistance, also implicated to play a role in PD. Interestingly, aging, stress and PD associate with an increase in cortisol and decrease in klotho, while physical exercise and certain genetic variations lead to a decrease in cortisol response and increased klotho. Here, we review the interrelated opposite actions of cortisol and klotho in the pathogenesis of PD. Together they impact powerful and divergent mechanisms that may go on to influence PD-related symptoms. Better understanding of these hormones in PD would facilitate the design of effective interventions that can simultaneously impact the multiple systems involved in the pathogenesis of PD.

Nutritional and Nutrition-Related Biomarkers as Prognostic Factors of Sarcopenia, and Their Role in Disease Progression

Due to the multifactorial pathogenesis of sarcopenia, it is crucial to identify biomarkers that are risk factors for sarcopenia, and which therefore have a prognostic function. Aim: This narrative review aims to define a set of biomarkers associated with nutrition and sarcopenia. These biomarkers could contribute to individualized monitoring and enable preventive and therapeutic methods. Methods: Two electronic databases, PubMed and Google Scholar, were used. The search strategy was based on a controlled vocabulary (MeSH) and includes studies published up to February 2022. Discussion: Higher levels of serum uric acid are associated with higher handgrip strength and better muscle function in elderly people and, thus, may slow the progression of sarcopenia. Leptin, an adipokine secreted by adipose tissue, promotes the production of pro-inflammatory cytokines, which in turn lead to sarcopenia. This makes leptin a significant indirect biomarker for physical disability and sarcopenic obesity. Additionally, creatinine is a reliable biomarker for muscle mass status because of its easy accessibility and cost-effectiveness. Vitamin D status acts as a useful biomarker for predicting total mortality, hip fractures, early death, and the development of sarcopenia. Therefore, there is an increasing interest in dietary antioxidants and their effects on age-related losses of muscle mass and function. On the other hand, 3-Methylhistidine is a valuable biomarker for detecting increased muscle catabolism, as it is excreted through urine during muscle degradation. In addition, IGF-1, whose concentration in plasma is stimulated by food intake, is associated with the loss of skeletal muscle mass, which probably plays a crucial role in the progression of sarcopenia. Conclusions: Many nutritional biomarkers were found to be associated with sarcopenia, and can therefore be used as prognostic indexes and risk factors. Nutrition plays an important role in the prevention and management of sarcopenia, affecting muscle mass, strength, and function in elderly people.

Safety Data in Patients with Autoimmune Diseases during Treatment with High Doses of Vitamin D3 According to the “Coimbra Protocol”

Background: In 2013, the group of Cicero Coimbra, Brazil, reported the clinical efficacy of high doses of vitamin D3 in patients suffering from autoimmune skin disorders (“Coimbra protocol”, CP). However, hypercalcemia and the subsequent impaired renal function may be major concerns raised against this protocol. Methods: We report for the first time for a broad spectrum of autoimmune diseases in 319 patients (mean age (±SD) 43.3 ± 14.6 years, 65.5% female, 34.5% male) safety data for high doses of orally applied vitamin D3 (treatment period: up to 3.5 years) accompanied by a strict low-calcium diet and regular daily fluid intake of at least 2.5 L. Results: Mean vitamin D3 dose was 35,291 ± 21,791 IU per day. The measurement of more than 6100 single relevant laboratory parameters showed all mean values (±SD) within the normal range for total serum calcium (2.4 ± 0.1 mmol/L), serum creatinine (0.8 ± 0.2 mg/dL), serum creatinine associated estimated GFR (92.5 ± 17.3 mL/min), serum cystatin C (0.88 ± 0.19 mg/L), serum TSH (1.8 ± 1 mIU/L), and for 24 h urinary calcium secretion (6.9 ± 3.3 mmol/24 h). We found a very weak relationship between the dosage of oral vitamin D3 and the subsequent calcium levels, both in serum and in urinary excretion over 24 h, respectively. Conclusions: Our data show the reliable safety of the CP in autoimmune patients under appropriate supervision by experienced physicians.

Vitamin D as a biomarker of health in snoring children: a familial aggregation study

BACKGROUND

Hypovitaminosis D is a common health problem. The purpose of this study was to investigate the inter-relationship between serum 25(OH)D levels and paternal and maternal vitamin D status in a sample of snoring children.

METHODS

We selected 137 participants for whom serum 25(OH)D had been measured and underwent overnight polysomnography evaluation. Serum glucose, lipids, liver enzymes, parathyroid hormone, insulin, and glycated hemoglobin were also measured. Glucose and insulin levels were used to estimate insulin resistance with the homeostasis model assessment (HOMA-IR).

RESULTS

Vitamin D insufficiency (<30 ng/mL) and deficiency (<20 ng/mL) were found in 40.9 and 17.5% of children, respectively. After adjustments for age, BMI z-score and seasonality, the odds ratio for risk of vitamin D insufficiency according to the vitamin D status of parents were: OR (95% CI): paternal insufficiency 15.1 (2.7-35.7), p = 0.002; maternal insufficiency 7.2 (2.4-22), p = 0.001. When children with vitamin D deficiency were analyzed separately, serum 25(OH)D concentration was found to be associated with the apnea-hypopnea index (r = -0.647, p = 0.009) and respiratory arousal index (r = -0.669, p = 0.034).

CONCLUSIONS

Family patterns of vitamin D could be helpful for the early identification of children at risk of metabolic and/or sleep disturbances and when considering strategies to improve vitamin D status.

IMPACT

Family patterns of vitamin D could be helpful for the early identification of snoring children at risk of metabolic and/or sleep disturbances. Significant associations were found between serum 25-hydroxyvitamin D (25(OH)D) concentrations in children and their parents. An inverse association between 25(OH)D levels and OSA severity was detected in deficient vitamin D children. Children with insufficient and deficient vitamin D status tended to have a worse metabolic profile, so strategies are needed to improve vitamin D status.

Insuficiência de vitamina D e fatores associados: um estudo com idosos assistidos por serviços de atenção básica à saúde

Resumo O objetivo deste artigo é analisar a insuficiência de vitamina D e fatores associados em idosos assistidos na atenção primária à saúde. Trata-se de um estudo transversal que avaliou 533 idosos (≥ 60 anos) em três cidades do estado de São Paulo, Brasil. Foi avaliada a 25-hidroxivitamina D (25 OH D) sérica por quimioluminescência. Os fatores avaliados foram condições sociodemográficas (sexo, faixa etária, etnia, escolaridade, renda, estado civil), de saúde (doenças referidas), composição corporal (IMC, circunferência da cintura), estilo de vida (atividade física e tabagismo) e exposição solar (finalidade, duração, frequência e horário de exposição, partes expostas, uso de protetor solar, tipo de pele). A prevalência de insuficiência foi de 64,5%, com associação para sexo feminino, etnia não brancos/não declarados, baixo peso, circunferência da cintura elevada (risco para DCV) e inatividade física. Houve associação negativa para exposição solar habitual de mãos, braços e pernas, durante atividade de lazer, deslocamentos diários e atividade física e entre as 9h e 15h. Os achados mostram a relevância de fatores como sexo, etnia, composição corporal, atividade física e hábitos de exposição solar na alta prevalência de níveis inadequados de vitamina D em idosos.

Vitamin D Supplementation and Cognition in Adults: A Systematic Review of Randomized Controlled Trials

BACKGROUND

The role of vitamin D supplementation in improving cognition and slowing the incidence of minor and major neurocognitive disorders is a matter of debate. To our knowledge, no systematic review of randomized controlled trials (RCTs) has examined this question in adults.

OBJECTIVES

The purpose of this systematic review is to synthesize the evidence regarding the effects of vitamin D supplementation on cognitive performance and neurocognitive disorders in adults.

METHODS

A systematic search of scientific articles in English or French was conducted. The MEDLINE (PubMed), EMBASE (Ovid, EMBASE), PsychINFO, and Cochrane Central databases were searched for records without any limit on publication date in May 2021. Inclusion criteria were (1) human participants, (2) RCT, (3) participant age ≥ 18, (4) vitamin D supplementation as the intervention, and (5) cognition (i.e., cognitive performance or cognitive status such as cognitively healthy or minor and major neurocognitive disorder) as the primary outcome. Two independent reviewers both assessed all eligible studies' full texts and the risk of bias arising from methodological issues using a standardized procedure.

RESULTS

Of the 2137 abstracts identified, 61 (2.9%) met screening inclusion criteria. After full text examination, 41 records (67.2%) were excluded. As a result, 20 RCTs (32.8%) were included in the systematic review. The review yielded mixed findings and, thus, failed to find evidence supporting cognitive benefits from vitamin D supplementation or suggesting a causal association between vitamin D and cognitive function. Half of the RCTs reported mixed results, one quarter negative results, and the last quarter positive effects for vitamin D supplementation on cognitive performance. The variability in serum 25-dihydroxyvitamin D concentration thresholds, the cognitive tests employed, the supplementation doses, and the samples' characteristics (i.e., ethnicity or number of participants) may explain these mixed findings.

CONCLUSION

This systematic review of RCTs does not support a role for vitamin D supplementation in enhancing cognition in adults.

Cholecalciferol (vitamin D3) has a direct protective activity against interleukin 6-induced atrophy in C2C12 myotubes

We previously determined that different vitamin D metabolites can have opposite effects on C2C12 myotubes, depending on the sites of hydroxylation or doses. Specifically, 25(OH)D₃ (25VD) has an anti-atrophic activity, 1,25(OH)₂D₃ induces atrophy, and 24,25(OH)₂D₃ is anti-atrophic at low concentrations and atrophic at high concentrations. This study aimed to clarify whether cholecalciferol (VD3) too, the non-hydroxylated upstream metabolite, has a direct effect on muscle cells.

Assessing the effects of VD3 treatment on mouse C2C12 skeletal muscle myotubes undergoing atrophy induced by interleukin 6 (IL6), we demonstrated that VD3 has a protective action, preserving C2C12 myotubes size, likely through promoting the differentiation and fusion of residual myoblasts and by modulating the IL6-induced autophagic flux. The lack, in C2C12 myotubes, of the hydroxylase transforming VD3 in the anti-atrophic 25VD metabolite suggests that VD3 may have a direct biological activity on the skeletal muscle. Furthermore, we found that the protective action of VD3 depended on VDR, implying that VD3 too might bind to and activate VDR. However, despite the formation of VDR-RXR heterodimers, VD3 effects do not depend on RXR activity.

In conclusion, VD3, in addition to its best-known metabolites, may directly impact on skeletal muscle homeostasis.

Early detection of accelerated aging and cellular decline (AACD): A consensus statement

The cellular hallmarks of accelerated aging and their clinical expression may be grouped using the terms 'accelerated aging and cellular decline' (AACD) and/or 'age-associated cellular decline'. This construct is designed to capture the biological background predisposing the development of age-related conditions. By classifying risk factors, early indicators, and clinical differentiators of AACD through expert consensus, this study aimed to identify the signs, symptoms, and markers indicative of AACD. In doing so, this work paves the way for future implementation of the AACD concept in the clinical and research settings. An interdisciplinary panel of experts with clinical and research expertise was selected to participate in a virtual workshop to discuss AACD. A modified nominal group technique was used to establish consensus among the group. An extended group of international experts critically reviewed an early draft of the manuscript, and their feedback was then incorporated into the model. Experts identified 13 factors predisposing to or clinically manifesting AACD. Among these, chronic diseases, obesity, and unfavorable genetic background were considered as the most important. There was a consensus that a gradual and nonspecific development often characterizes AACD, making its clinical detection potentially challenging. In addition, signs and symptoms might have multifactorial causes and overlapping origins, such as genetic and epigenetic predispositions. As a result, an initial checklist was outlined, listing clinical factors of special relevance (e.g., fatigue, low quality of sleep, and low mood) to represent early manifestations of the organism's exhaustion, which are also frequently neglected in the clinical setting. Differentiating AACD from other conditions is essential. The use of a combination of biomarkers was proposed as a viable method in a two-step process of differentiation: 1) identification of early AACD clinical indicators, followed by 2) symptom and biomarker confirmation with a focus on system domains (to be potentially targeted by future specific interventions). Although the AACD construct is not yet ready for routine use in clinical practice, its operationalization may support the early identification of age-related conditions (when this might still be amenable to reversion) and also encourage preventative interventions. Further investigation is needed to establish specific biomarkers that confirm independent risk factors for AACD and provide a more definitive structure to the concept of AACD (and age-associated cellular decline).

Nutritional Biomarkers and Associated Factors in Community-Dwelling Older Adults: Findings from the SHIELD Study

Aging is associated with intrinsic and extrinsic changes which affect the nutrient intake and nutritional status of an older individual. Suboptimal nutritional status is linked with adverse health outcomes. There are limited data in this area for community-dwelling older adults who are not at risk of malnutrition. The objective of this study was to describe the nutritional biomarkers in 400 community-dwelling older adults (aged ≥65 years) with normal nutritional status (Malnutrition Universal Screening Test score of 0) in Singapore and to identify factors associated with these biomarkers. The majority of the participants had normal levels of pre-albumin, albumin, total protein, creatinine, zinc, corrected calcium, vitamin B12, ferritin and hemoglobin. Females had significantly higher levels of corrected calcium and vitamin B12 than males, whereas males had significantly higher levels of pre-albumin, albumin, creatinine, serum ferritin, 25-hydroxyvitamin D (25(OH)D) and hemoglobin than females. About half of the participants (52%) had low level of 25(OH)D (<30 μg/L) and 10% had low zinc level (<724 μg/L). Among those with low level of 25(OH)D, 74% had 25(OH)D insufficiency (20–<30 μg/L) and 26% had 25(OH)D deficiency (<20 μg/L). Younger age, female gender, non-Chinese ethnicity and no intake of vitamin D supplement were associated with lower serum 25(OH)D level, whereas higher body mass index (BMI) was associated with low zinc level. These findings highlight the problem of hidden nutritional insufficiencies can be missed in seemingly normal nourished community-dwelling older adults.

The predictive role of circulating telomerase and vitamin D for long-term survival in patients undergoing coronary artery bypass grafting surgery (CABG)

Backgrounds

Cardiovascular disease (CVD) is the leading cause of mortality all over the globe. Inflammation is believed to play a pivotal role in the pathophysiology of CVD. While there are studies on the interrelationship of telomerase and vitamin D and their involvement in CVD, their independent contributions to long-term outcomes in patients with CVD are not well-defined. This study aimed to investigate the association of both telomerase and vitamin D concentrations with 10-year survival among candidates of coronary artery bypass grafting (CABG) surgery.

Methods

Participants were 404 patients from Tehran Heart Center-Coronary Outcome Measurement (THC-COM) cohort who were recruited from CABG surgery candidates in 2006. In addition to demographic and clinical data including risk factors for coronary artery disease, laboratory parameters such as markers of inflammation as well as baseline serum 25-hydroxy vitamin D [25(OH)D] and telomerase concentrations were measured. Cardiac function indexes alongside outcome measures such as mortality and survival days were recorded for every patient up to 10 years after CABG. Cox-proportional hazard model was used to study the association between all-cause mortality and research parameters.

Results

The mean serum telomerase enzyme level was 24.92 ±21.4 nmol/L and the mean serum 25(OH)D was 27.27±10.3 ng/mL. 10-year mortality was reported in 64 (15.8%) patients. 25(OH)D was categorized into three groups (<20, 20–30, and >30) and the cut-point for telomerase was set at 25.0 nmol/L. In Cox regression analysis, higher levels of telomerase (>25 nmol/L) were significantly associated with longer survival (p = 0.041), whereas 25(OH)D concentrations were not associated with survival time. Further analysis showed that telomerase concentrations significantly predicted survival only in the presence of insufficient levels of 25(OH)D (20–30 ng/mL) (p = 0.037).

Conclusions

Telomerase can be regarded as a potential predictor of long-term outcomes in patients who underwent CABG. However, the association of telomerase with the mortality may be modified by vitamin D concentrations.

Sunlight and health: shifting the focus from vitamin D3 to photobiomodulation by red and near-infrared light

Both sun exposure and serum vitamin D levels have been associated with lower risks of all-cause mortality and chronic age-related diseases, e.g., cancer, diabetes and cardiovascular disease, in epidemiological studies. These associations have mainly been ascribed to beneficial effects of vitamin D. However, a vast body of randomized controlled trials (RCTs) and Mendelian randomization studies have failed to confirm any major health benefits from vitamin D supplementation. In this review, we present tentative evidence showing that red and near-infrared light, both being present in sunlight, could explain the associations between sunlight exposure and better health status. Body irradiation with red and near-infrared light, usually termed as photobiomodulation (PBM), has demonstrated beneficial effects in animal models of chronic diseases. Beyond this, preliminary evidence from RCTs suggest potential clinical benefit from PBM for chronic diseases. PBM is currently being investigated in many pre-registered clinical trials, results of which will eventually clarify the role of red and near-infrared light in the prevention and treatment of common age-related chronic diseases.

Tripartite Combination of Candidate Pandemic Mitigation Agents: Vitamin D, Quercetin, and Estradiol Manifest Properties of Medicinal Agents for Targeted Mitigation of the COVID-19 Pandemic Defined by Genomics-Guided Tracing of SARS-CoV-2 Targets in Human Cells

Genes required for SARS-CoV-2 entry into human cells, ACE2 and FURIN, were employed as baits to build genomic-guided molecular maps of upstream regulatory elements, their expression and functions in the human body, and pathophysiologically relevant cell types. Repressors and activators of the ACE2 and FURIN genes were identified based on the analyses of gene silencing and overexpression experiments as well as relevant transgenic mouse models. Panels of repressors (VDR; GATA5; SFTPC; HIF1a) and activators (HMGA2; INSIG1; RUNX1; HNF4a; JNK1/c-FOS) were then employed to identify existing drugs manifesting in their effects on gene expression signatures of potential coronavirus infection mitigation agents. Using this strategy, vitamin D and quercetin have been identified as putative 2019 coronavirus disease (COVID-19) mitigation agents. Quercetin has been identified as one of top-scoring candidate therapeutics in the supercomputer SUMMIT drug-docking screen and Gene Set Enrichment Analyses (GSEA) of expression profiling experiments (EPEs), indicating that highly structurally similar quercetin, luteolin, and eriodictyol could serve as scaffolds for the development of efficient inhibitors of SARS-CoV-2 infection. In agreement with this notion, quercetin alters the expression of 98 of 332 (30%) of human genes encoding protein targets of SARS-CoV-2, thus potentially interfering with functions of 23 of 27 (85%) of the SARS-CoV-2 viral proteins in human cells. Similarly, Vitamin D may interfere with functions of 19 of 27 (70%) of the SARS-CoV-2 proteins by altering expression of 84 of 332 (25%) of human genes encoding protein targets of SARS-CoV-2. Considering the potential effects of both quercetin and vitamin D, the inference could be made that functions of 25 of 27 (93%) of SARS-CoV-2 proteins in human cells may be altered. GSEA and EPEs identify multiple drugs, smoking, and many disease conditions that appear to act as putative coronavirus infection-promoting agents. Discordant patterns of testosterone versus estradiol impacts on SARS-CoV-2 targets suggest a plausible molecular explanation of the apparently higher male mortality during the coronavirus pandemic. Estradiol, in contrast with testosterone, affects the expression of the majority of human genes (203 of 332; 61%) encoding SARS-CoV-2 targets, thus potentially interfering with functions of 26 of 27 SARS-CoV-2 viral proteins. A hypothetical tripartite combination consisting of quercetin/vitamin D/estradiol may affect expression of 244 of 332 (73%) human genes encoding SARS-CoV-2 targets. Of major concern is the ACE2 and FURIN expression in many human cells and tissues, including immune cells, suggesting that SARS-CoV-2 may infect a broad range of cellular targets in the human body. Infection of immune cells may cause immunosuppression, long-term persistence of the virus, and spread of the virus to secondary targets. Present analyses and numerous observational studies indicate that age-associated vitamin D deficiency may contribute to the high mortality of older adults and the elderly. Immediate availability for targeted experimental and clinical interrogations of potential COVID-19 pandemic mitigation agents, namely vitamin D and quercetin, as well as of the highly selective (Ki, 600 pm) intrinsically specific FURIN inhibitor (a1-antitrypsin Portland (a1-PDX), is considered an encouraging factor. Observations reported in this contribution are intended to facilitate follow-up targeted experimental studies and, if warranted, randomized clinical trials to identify and validate therapeutically viable interventions to combat the COVID-19 pandemic. Specifically, gene expression profiles of vitamin D and quercetin activities and their established safety records as over-the-counter medicinal substances strongly argue that they may represent viable candidates for further considerations of their potential utility as COVID-19 pandemic mitigation agents. In line with the results of present analyses, a randomized interventional clinical trial evaluating effects of estradiol on severity of the coronavirus infection in COVID19+ and presumptive COVID19+ patients and two interventional randomized clinical trials evaluating effects of vitamin D on prevention and treatment of COVID-19 were listed on the ClinicalTrials.gov website.

Immunomodulatory Effects of Vitamin D in Thyroid Diseases

Vitamin D is a secosteroid with a pleiotropic role in multiple physiological processes. Besides the well-known activity on bone homeostasis, recent studies suggested a peculiar role of vitamin D in different non-skeletal pathways, including a key role in the modulation of immune responses. Recent evidences demonstrated that vitamin D acts on innate and adaptative immunity and seems to exert an immunomodulating action on autoimmune diseases and cancers. Several studies demonstrated a relationship between vitamin D deficiency, autoimmune thyroid disorders, and thyroid cancer. This review aims to summarize the evidences on the immunomodulatory effect of vitamin D on thyroid diseases.

Pathophysiological Role and Therapeutic Implications of Vitamin D in Autoimmunity: Focus on Chronic Autoimmune Diseases

Vitamin D is a pleiotropic secosteroid yielding multiple actions in human physiology. Besides the canonical regulatory activity on bone metabolism, several non-classical actions have been described and the ability of vitamin D to partake in the regulation of the immune system is particularly interesting, though far stronger and convincing evidence has been collected in in vitro as compared to in vivo studies. Whether vitamin D is able to regulate at physiological concentrations the human immune system remains unproven to date. Consequently, it is not established if vitamin D status is a factor involved in the pathogenesis of immune-mediated diseases and if cholecalciferol supplementation acts as an adjuvant for autoimmune diseases. The development of autoimmunity is a heterogeneous process, which may involve different organs and systems with a wide range of clinical implications. In the present paper, we reviewed the current evidences regarding vitamin D role in the pathogenesis and management of different autoimmune diseases.

Efficacy of Vitamin D3 Buccal Spray Supplementation Compared to Other Delivery Methods: A Systematic Review of Superiority Randomized Controlled Trials

(1) Background: Vitamin D deficiency is an important public health concern and supplementation is common for this deficiency. Many different modes of delivering supplementation have been proposed in order to enhance absorption and utilization. The present review compared the efficacy of vitamin D3 buccal spray against other forms of supplementation delivery. (2) Methods: The protocol was registered at PROSPERO (CRD42019136146). Medline/PubMed, CENTRAL and clinicaltrials.gov were searched from their inception until September 2019, for randomized controlled trials (RCTs) that compare vitamin D3 delivery via sublingual spray against other delivery methods. Eligible RCTs involved humans, of any age and health status, published in any language that evaluated changes in plasma 25(OH)D concentrations. Three reviewers independently extracted data, assessed risk of bias (RoB) and the quality of the trials. (3) Results: Out of 9759 RCTs, four matched the predefined criteria. Intervention duration ranged from 30 days to 3 months whereas vitamin D3 dosage ranged between 800 and 3000 IU/day. One RCT advocated for the superiority of buccal spray in increasing plasma 25(OH)D concentrations, although several limitations were recorded in that trial. The rest failed to report differences in post-intervention 25(OH)D concentrations between delivery methods. Considerable clinical heterogeneity was observed due to study design, intervention duration and dosage, assays and labs used to perform the assays, population age and health status, not allowing for synthesis of the results. (4) Conclusions: Based on the available evidence, delivery of vitamin D3 via buccal spray does not appear superior to the other modes of delivery. Future RCTs avoiding the existing methodological shortcomings are warranted.