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

Variability in response to vitamin D supplementation according to vitamin D metabolism related gene polymorphisms in healthy adults

OBJECTIVE

The aim of this study was to determine the influence of polymorphisms in some key gene actors of the vitamin D (vitD) metabolic pathway on supplementation efficacy.

METHODS

In total, 245 healthy participants were recruited from occupational medicine service in Sahloul University Hospital with vitD deficiency [25(OH)D ≤ 30 ng/ml]. After giving an informed consent, all participants were asked to complete a generalized questionnaire and to follow a detailed personalized supplementation protocol. Genetic study was performed by PCR-RFLP for 15 single nucleotide polymorphisms (SNPs) belonging to DBP, CYP2R1, CYP27B14, CYP24A1 and VDR genes. Statistical study was carried out with SPSS23.0.

RESULTS

Among the studied SNPs, non-response was significantly associated with variant alleles of rs4588 (OR* = 11.51; p < 0.001), rs10766197 (OR* = 6.92; p = 0.008) and rs12794714 (OR* = 5.09; p = 0.004). These three SNPs contributed in 18.8% in response variability with rs4588 being the most influential (10.3%). There was a significant linear negative correlation between baseline 25(OH)D and post supplementation 25(OH)D concentration (r = -0.437; p < 0.001) as well as a linear negative association between the increase in 25(OH)D concentration and GRS (GRS: genetic risk score = the sum of risk alleles) (r = -0.149; p = 0.033).

CONCLUSIONS

DBP-rs4588, CYP2R1-rs10766197 and rs12794714 variants are associated with variations in serum 25(OH)D concentrations and efficacy of response to vitD supplementation in Tunisian adults. Taking into account these variations can help to better adapt vitD intake to ensure a higher response to supplementation.

Clinical, metabolic, and immunological characterisation of adult Ugandan patients with new-onset diabetes and low vitamin D status

BACKGROUND

Low vitamin D concentrations are associated with metabolic derangements, notably insulin resistance and pancreatic beta-cell dysfunction in Caucasian populations. Studies on its association with the clinical, metabolic, and immunologic characteristics in black African adult populations with new-onset diabetes are limited. This study aimed to describe the clinical, metabolic, and immunologic characteristics of a black Ugandan adult population with recently diagnosed diabetes and hypovitaminosis D.

METHODS

Serum vitamin D concentrations were measured in 327 participants with recently diagnosed diabetes. Vitamin D deficiency, vitamin D insufficiency, and normal vitamin D status were defined as serum 25 hydroxyvitamin D levels of < 20 ng/ml, 21-29 ng/ml, and ≥ 30 ng/ml, respectively.

RESULTS

The median (IQR) age, glycated haemoglobin, and serum vitamin D concentration of the participants were 48 years (39-58), 11% (8-13) or 96 mmol/mol (67-115), and 24 ng/ml (18-30), respectively. Vitamin D deficiency, vitamin D insufficiency, and normal vitamin D status were noted in 105 participants (32.1%), 140 participants (42.8%), and 82 participants (25.1%), respectively. Compared with those having normal serum vitamin D levels, participants with vitamin D deficiency and insufficiency had higher circulating concentrations of interleukin (IL) 6 (29 [16-45] pg/ml, 23 [14-40] pg/ml vs 18 [14-32] pg/ml, p = 0.01), and IL-8 (24 [86-655] pg/ml, 207 [81-853] pg/ml vs 98 [67-224], p = 0.03). No statistically significant differences were noted in the markers of body adiposity, insulin resistance, and pancreatic beta-cell function between both groups.

CONCLUSION

Vitamin D deficiency and insufficiency were highly prevalent in our study population and were associated with increased circulating concentrations of pro-inflammatory cytokines. The absence of an association between pancreatic beta-cell function, insulin resistance, and low vitamin D status may indicate that the latter does not play a significant role in the pathogenesis of type 2 diabetes in our adult Ugandan population.

Comparing the Evidence from Observational Studies and Randomized Controlled Trials for Nonskeletal Health Effects of Vitamin D

Although observational studies of health outcomes generally suggest beneficial effects with, or following, higher serum 25-hydroxyvitamin D [25(OH)D] concentrations, randomized controlled trials (RCTs) have generally not supported those findings. Here we review results from observational studies and RCTs regarding how vitamin D status affects several nonskeletal health outcomes, including Alzheimer’s disease and dementia, autoimmune diseases, cancers, cardiovascular disease, COVID-19, major depressive disorder, type 2 diabetes, arterial hypertension, all-cause mortality, respiratory tract infections, and pregnancy outcomes. We also consider relevant findings from ecological, Mendelian randomization, and mechanistic studies. Although clear discrepancies exist between findings of observational studies and RCTs on vitamin D and human health benefits these findings should be interpreted cautiously. Bias and confounding are seen in observational studies and vitamin D RCTs have several limitations, largely due to being designed like RCTs of therapeutic drugs, thereby neglecting vitamin D’s being a nutrient with a unique metabolism that requires specific consideration in trial design. Thus, RCTs of vitamin D can fail for several reasons: few participants’ having low baseline 25(OH)D concentrations, relatively small vitamin D doses, participants’ having other sources of vitamin D, and results being analyzed without consideration of achieved 25(OH)D concentrations. Vitamin D status and its relevance for health outcomes can usefully be examined using Hill’s criteria for causality in a biological system from results of observational and other types of studies before further RCTs are considered and those findings would be useful in developing medical and public health policy, as they were for nonsmoking policies. A promising approach for future RCT design is adjustable vitamin D supplementation based on interval serum 25(OH)D concentrations to achieve target 25(OH)D levels suggested by findings from observational studies.

Higher dietary vitamin D intake is associated with better survival among older women: Results from the French EPIDOS cohort

Background

Hypovitaminosis D, a condition highly common among older adults, is associated with 35-percent increased all-cause mortality. In contrast, vitamin D supplementation prevents all-cause mortality. The possible role of the dietary intake of vitamin D on mortality remains yet unknown.

Objectives

The objective of this prospective study was to determine all-cause mortality risk according to baseline dietary vitamin D intake among older adults while accounting for potential confounders including dietary calcium intake.

Methods

Vitamin D and calcium dietary intakes were estimated at baseline from a self-administered food frequency questionnaire among 3,066 community-dwelling older women aged ≥75 years, recruited in the French EPIDOS cohort between 1992 and 1994, and for whom information about vital status was available in 2010. Dietary vitamin D and calcium intakes were defined as low if <400 IU/day or <1,200 mg/day, respectively.

Results

The mean ± SD age of the whole cohort was 80.1 ± 3.6 years at baseline. The median survival time from baseline for participants with low dietary vitamin D intake was 11.5 years [95% confidence interval (CI): 11.0–11.9] vs. 12.2 years (95% CI: 11.7–12.9) for those consuming more than 400 IU/day (p = 0.003). Among those with calcium dietary intake <1,200 mg/day, a vitamin D consumption of 400 IU/day and over had a significant positive effect on all-cause mortality (RR: 0.86, p < 0.05). However, no association was retrieved between dietary vitamin D intake and all-cause mortality among participants with dietary calcium intake ≥1,200 mg/day.

Conclusion

Higher dietary vitamin D intake was associated with better survival in the study cohort, specifically among those consuming <1,200 mg/day of dietary calcium.

Occurrence of metabolic syndrome components in northerners

The metabolic syndrome is currently becoming more common. It is a significant public health concern as it is epidemic affecting populations in many regions of the world. In Magadan region no research has been carried out to study the frequency of components of the metabolic syndrome among northerners. This survey was performed to assess the occurrence of the main and additional components of the metabolic syndrome among 17 to 74 year old residents of the Northern region. Two hundred and forty north born Caucasians participated in the study: male subjects at their young age, working age, and retirement age, all belonging to the territory of Magadan region. We used photometric, immunochemiluminescent research methods, as well as standard methods for assessing body mass index and cardiovascular system. The metabolic syndrome factors were determined in accordance with the criteria of the National Cholesterol Education Program (NCEP), the Adult Treatment Program III (ATP III), the International Diabetes Federation (IDF), and the Consensus of International Experts in Cardiology and Endocrinology. We analyzed five main components of the metabolic syndrome (overweight, carbohydrate metabolic impairments hypertension, hypertriglyceridemia, hypoalphacholesterolemia) and three additional components (presence of insulin resistance, purine metabolism disorder, deficient and insufficient concentrations of vitamin D). Combinations of the components were also studied through the examined age groups. According to the ATP III, NCEP and IDF criteria, the metabolic syndrome was more common in elderly subjects (47%) than in working age (21%) or young examinees (3%). Older males tended to exhibit higher frequency of both the main and additional factors of metabolic syndrome. The total index of the occurrence of metabolic syndrome factors in the group of young men was 101%; in the group of men of working age - 180%, and in men of retirement age - 274%. The results on occurrence of the metabolic syndrome components observed in the surveyed groups of northerners can make an information data base, which we assume can be applied when planning and carrying out scientifically grounded preventive measures, which will improve subjective quality of life and its expectancy under the North conditions.

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.

METHODS

2423 participants were randomized to 4000 IU/day of vitamin D₃ or placebo and followed for median 3.0 years for new-onset diabetes. In pre-specified secondary analyses, we examined the effect of vitamin D supplementation on composite Major Adverse Cardiovascular Events (MACE); expanded MACE (MACE + revascularization); atherosclerotic CVD (ASCVD) risk score; and individual CVD risk factors (blood pressure, lipids, high-sensitivity C-reactive protein). Cox models compared hazard ratios (HR) between the two groups on MACE and expanded MACE.

RESULTS

Mean age was 60 years, 45 % were women, 13 % had history of CVD. Twenty-one participants assigned to vitamin D and 12 participants assigned to placebo met the MACE outcome (HR 1.81, 95%CI 0.89 to 3.69). There were 27 expanded MACE outcomes in each group (HR 1.02, 95%CI, 0.59 to 1.76). There were no significant differences between vitamin D and placebo in individual CVD risk factors, but change in ASCVD risk score favored the vitamin D group (-0.45 %, 95%CI -0.75 to -0.15).

CONCLUSIONS

In people with prediabetes not selected for vitamin D insufficiency and with intermediate CVD risk, vitamin D supplementation did not decrease MACE but had a small favorable effect on ASCVD risk score.

TRIAL REGISTRATION

D2d ClinicalTrials.gov number, NCT01942694, prospectively registered September 16, 2013.

Respiratory Tract Infections in Diabetes - Lessons From Tuberculosis and Influenza to Guide Understanding of COVID-19 Severity

Patients with type-2 diabetes (T2D) are more likely to develop severe respiratory tract infections. Such susceptibility has gained increasing attention since the global spread of Coronavirus Disease 2019 (COVID-19) in early 2020. The earliest reports marked T2D as an important risk-factor for severe forms of disease and mortality across all adult age groups. Several mechanisms have been proposed for this increased susceptibility, including pre-existing immune dysfunction, a lack of metabolic flexibility due to insulin resistance, inadequate dietary quality or adverse interactions with antidiabetic treatments or common comorbidities. Some mechanisms that predispose patients with T2D to severe COVID-19 may indeed be shared with other previously characterized respiratory tract infections. Accordingly, in this review, we give an overview of response to Influenza A virus and to Mycobacterium tuberculosis (Mtb) infections. Similar risk factors and mechanisms are discussed between the two conditions and in the case of COVID-19. Lastly, we address emerging approaches to address research needs in infection and metabolic disease, and perspectives with regards to deployment or repositioning of metabolically active therapeutics.

Characterization of methylation patterns associated with lifestyle factors and vitamin D supplementation in a healthy elderly cohort from Southwest Sweden

Numerous studies have shown that lifestyle factors, such as regular physical activity and vitamin D intake, may remarkably improve overall health and mental wellbeing. This is especially important in older adults whose vitamin D deficiency occurs with a high prevalence. This study aimed to examine the influence of lifestyle and vitamin D on global DNA methylation patterns in an elderly cohort in Southwest of Sweden. We also sought to examine the methylation levels of specific genes involved in vitamin D's molecular and metabolic activated pathways. We performed a genome wide methylation analysis, using Illumina Infinium DNA Methylation EPIC 850kBeadChip array, on 277 healthy individuals from Southwest Sweden at the age of 70–95. The study participants also answered queries on lifestyle, vitamin intake, heart medication, and estimated health. Vitamin D intake did not in general affect methylation patterns, which is in concert with other studies. However, when comparing the group of individuals taking vitamin supplements, including vitamin D, with those not taking supplements, a difference in methylation in the solute carrier family 25 (SCL25A24) gene was found. This confirms a previous finding, where changes in expression of SLC25A24 were associated with vitamin D treatment in human monocytes. The combination of vitamin D intake and high physical activity increased methylation of genes linked to regulation of vitamin D receptor pathway, the Wnt pathway and general cancer processes. To our knowledge, this is the first study detecting epigenetic markers associated with the combined effects of vitamin D supplementation and high physical activity. These results deserve to be further investigated in an extended, interventional study cohort, where also the levels of 25(OH)D₃ can be monitored.

Rapidly Increasing Serum 25(OH)D Boosts the Immune System, against Infections-Sepsis and COVID-19

Vitamin D deficiency is a global public health problem, a pandemic that commonly affects the elderly and those with comorbidities such as obesity, diabetes, hypertension, respiratory disorders, recurrent infections, immune deficiency, and malignancies, as well as ethnic minorities living in temperate countries. The same groups were worst affected by COVID-19. Since vitamin D deficiency weakens the immune system, it increases the risk of infections, complications, and deaths, such as from sepsis and COVID-19. Deficiency can be remedied cost-effectively through targeted food fortification, supplementation, and/or daily safe sun exposure. Its endocrine functions are limited to mineral metabolism, musculoskeletal systems, specific cell membrane interactions, and parathyroid gland functions. Except for the rapid, endocrine, and cell membrane-based non-genomic functions, all other biological and physiological activities of vitamin D depend on the adequate intracellular synthesis of 1,25(OH)2D (calcitriol) in peripheral target cells via the genome. Calcitriol mediates autocrine (intracrine) and paracrine signalling in immune cells, which provides broader, protective immune functions crucial to overcoming infections. The synthesis of 1,25(OH)2D (calcitriol) in peripheral target cells is dependent on diffusion and endocytosis of D3 and 25(OH)D from the circulation into them, which requires maintenance of serum 25(OH)D concentration above 50 ng/mL. Therefore, in acute infections such as sepsis and respiratory infections like COVID-19, it is necessary to rapidly provide its precursors, D3 and 25(OH)D, through the circulation to generate adequate intracellular calcitriol. Immune defence is one of the crucial non-hormonal functions of vitamin D. A single oral (bolus) dose or divided upfront loading doses between 100,000 and 500,000 IU, using 50,000 IU vitamin D3 increase the serum 25(OH)D concentrations to a therapeutic level of above 50 ng/mL that lasts between two to three months. This takes three to five days to raise serum 25(OH)D. In contrast, a single oral dose of calcifediol (0.014 mg/kg body weight) can generate the needed 25(OH)D concentration within four hours. Considering both D3 and 25(OH)D enter immune cells for generating calcitriol, using the combination of D3 (medium-term) and calcifediol (immediate) is cost-effective and leads to the best clinical outcome. To maximise protection against infections, particularly to reduce COVID-19-associated complications and deaths, healthcare workers should advise patients on safe sun exposure, adequate vitamin D supplementation and balanced diets containing zinc, magnesium, and other micronutrients to support the immune system. Meanwhile, governments, the World Health Organisation, the Centers for Disease Control, and governments should consider similar recommendations to physicians and the public, change the outdated vitamin D and other micronutrient recommendations directed to their population, and organise targetted food fortification programs for the vulnerable groups. This article discusses a rational approach to maintaining a sustained serum 25(OH)D concentration above 50 ng/mL, necessary to attain a robust immune system for overcoming infections. Such would cost-effectively improve the population’s health and reduce healthcare costs. It also describes three cost-effective, straightforward protocols for achieving and sustaining therapeutic serum 25(OH)D concentrations above 50 ng/mL (>125 nmol/L) to keep the population healthy, reduce absenteeism, improve productivity, and lower healthcare costs.

An Exploration of How Solar Radiation Affects the Seasonal Variation of Human Mortality Rates and the Seasonal Variation in Some Other Common Disorders

Many diseases have large seasonal variations in which winter overall mortality rates are about 25% higher than in summer in mid-latitude countries, with cardiovascular diseases and respiratory infections and conditions accounting for most of the variation. Cancers, by contrast, do not usually have pronounced seasonal variations in incidence or mortality rates. This narrative review examines the epidemiological evidence for seasonal variations in blood pressure, cardiovascular disease rates and respiratory viral infections in relation to atmospheric temperature and humidity, and solar UV exposure through vitamin D production and increased blood concentrations of nitric oxide. However, additional mechanisms most likely exist by which solar radiation reduces the risk of seasonally varying diseases. Some studies have been reported with respect to temperature without considering solar UV doses, although studies regarding solar UV doses, such as for respiratory infections, often consider whether temperature can affect the findings. More research is indicated to evaluate the relative effects of temperature and sun exposure on the seasonality of mortality rates for several diseases. Since solar ultraviolet-B (UVB) doses decrease to vanishingly small values at higher latitudes in winter, the use of safe UVB lamps for indoor use in winter may warrant consideration.

Association of Serum 25(OH)D, Cadmium, CRP With All-Cause, Cause-Specific Mortality: A Prospective Cohort Study

Introduction

To explore the relationship between serum 25(OH)D, cadmium, and CRP with all-cause mortality among people in diabetic and non-diabetic.

Methods

This study used data from the NHANES (2001–2010). Cox regression was used to analyze the relationship between Serum 25(OH)D, cadmium, CRP, and all-cause, cause-specific mortality. We used restricted cubic splines to explore the dose-response relationship between serum 25(OH)D, cadmium, CRP, and all-cause mortality.

Results

During a mean follow-up of 9.1 years, the study included 20,221 participants, 2,945 people with diabetes, and 17,276 people without diabetes. Compared with serum 25(OH)D deficiency group in diabetic patients, the sufficient serum 25(OH)D group was associated with lower all-cause mortality (HR = 0.41, 95%CI 0.28-0.60, P < 0.001) and cardiovascular mortality (HR = 0.46, 95%CI 0.22–0.95, P = 0.04). Compared with the low cadmium group, the high cadmium group was associated with higher all-cause mortality (HR = 1.49, 95%CI 1.06–2.09, P = 0.02). Compared with the low CRP group, the high CRP group was associated with higher all-cause mortality (HR = 1.65, 95%CI 1.24–2.19, P = 0.001) and cancer mortality (HR = 3.25, 95%CI 1.82–5.80, P < 0.001). Restricted cubic splines analysis showed a significant nonlinear association between serum 25(OH)D (P-nonlinearity P < 0.001), cadmium (P-nonlinearity = 0.002), CRP (P-nonlinearity = 0.003), and HR for all-cause mortality risk in diabetic patients. The results were similar among non-diabetic patients, but with different levels of risk. Sensitivity analysis and subgroup analysis presented the results of population studies with different follow-up times, different genders and ages.

Conclusions

In diabetic patients, serum 25(OH)D, cadmium, and CRP were related to all-cause mortality; serum 25(OH)D was related to cardiovascular mortality; CRP was related to cancer mortality. The results were similar among non-diabetic patients, but with different levels of risk.

A randomized, double-blind, placebo-controlled trial of vitamin D supplementation with or without calcium in community-dwelling vitamin D deficient subjects

BACKGROUND

Although vitamin D deficiency is highly prevalent in the Middle East, very few studies have attempted to measure its health impact.

AIMS

We aimed to assess whether vitamin D3 and calcium, either alone or in combination, have health benefit.

METHODS

In a 2 × 2 factorial design double-blind, placebo-controlled trial, Community free living adults living in the city of Al Ain, UAE were randomly assigned to receive daily 2000 IU oral vitamin D3 alone, 600 mg calcium alone, oral vitamin D3 (2000 IU per day) combined with 600 mg calcium, or a placebo for 6 months. Primary outcomes were self-rated health and bone turnover markers.

RESULTS

Of the 545 randomized, 277 subjects completed 6 months follow up. 25(OH)D levels marginally increased in the two groups received vitamin D3 alone or combined with calcium compared to the decline seen in those who received calcium supplement alone or a placebo. Sub-group analysis revealed that parathyroid hormone (PTH) concentration decreased and Calcium/creatinine ratio increased significantly in the combined vitamin D and Calcium group compared to the vitamin D alone or Calcium alone in contrast to the increase seen in the placebo group [p < 0.05 for between group difference at 6 months]. There were no statistically significant differences between the supplement and placebo groups at the 6 months follow-up in body weight, body mass index (BMI), blood pressure, body pains and general health.

CONCLUSION

PTH concentration decreased and calcium/creatinine ratio increased in subjects who received vitamin D and Calcium together compared to those who received vitamin D alone.

TRIAL REGISTRATION

NCT02662491 , First registered on 25 January 2016 ( https://register.

CLINICALTRIALS

gov/prs/app/action/SelectProtocol?sid=S00060CE&selectaction=Edit&uid=U0001M6P&ts=3&cx=scu4cb , Last update: 05 August 2019.

Association between vitamin D status and lifestyle factors in Brazilian women: Implications of Sun Exposure Levels, Diet, and Health

BACKGROUND

Vitamin D deficiency has been documented to be prevalent, even in low latitude regions; and this may be related to sun exposure behaviors. The aim of the current study was to assess the association between serum 25-hydroxyvitamin D [25(OH)D] concentrations and lifestyle-related factors in a sample of Brazilian women living at latitude 21º 8' S.

METHODS

A cross-sectional study was undertaken in 101 women aged 35 years or older in July 2019 to assess the association between 25(OH)D concentration and level of exposure to ultraviolet radiation (UVR), smoking habits, alcohol consumption, and physical activity levels. Age, body mass index (BMI), and postmenopausal status were investigated.

FINDINGS

According to the slope coefficient for individual daily UVR levels, the concentration of 25(OH)D increased by 5 nmol / L for each extra Standard Erythema Dose of UVR, regardless of age and BMI (p < 0·001). Postmenopausal women had a significantly higher mean concentration of 25(OH)D (p = 0·01), higher UVR exposure (p = 0·01) and lower BMI (p = 0·005) compared with younger women, independent of other confounders including smoking, alcohol, occupation and physical activity.

INTERPRETATION

Although postmenopausal women from Brazil had higher mean concentrations of 25(OH)D than younger women, more studies are necessary to understand how sun exposure and lifestyle variables interfere with these levels. These findings have important public health implications since they suggest that vitamin D deficiency in older age is not inevitable.

FUNDING

This study was funded by an award received by Universities Global Partnership Network - UGPN. KVSS and SLO receive scholarship from CAPES, Brazilian Ministry of Education. HR receives a productivity grant from CNPq.

The Role of Vitamin D in Supporting Health in the COVID-19 Era

The genomic activity of vitamin D is associated with metabolic effects, and the hormone has a strong impact on several physiological functions and, therefore, on health. Among its renowned functions, vitamin D is an immunomodulator and a molecule with an anti-inflammatory effect, and, recently, it has been much studied in relation to its response against viral infections, especially against COVID-19. This review aims to take stock of the correlation studies between vitamin D deficiency and increased risks of severe COVID-19 disease and, similarly, between vitamin D deficiency and acute respiratory distress syndrome. Based on this evidence, supplementation with vitamin D has been tested in clinical trials, and the results are discussed. Finally, this study includes a biochemical analysis on the effects of vitamin D in the body's defense mechanisms against viral infection. In particular, the antioxidant and anti-inflammatory functions are considered in relation to energy metabolism, and the potential, beneficial effect of vitamin D in COVID-19 is described, with discussion of its influence on different biochemical pathways. The proposed, broader view of vitamin D activity could support a better-integrated approach in supplementation strategies against severe COVID-19, which could be valuable in a near future of living with an infection becoming endemic.

Mitophagy and mitochondrial dynamics in type 2 diabetes mellitus treatment

The prevalence of type 2 diabetes is associated with inflammatory bowels diseases, nonalcoholic steatohepatitis and even a spectrum of cancer such as colon cancer and liver cancer, resulting in a substantial healthcare burden on our society. Autophagy is a key regulator in metabolic homeostasis such as lipid metabolism, energy management and the balance of cellular mineral substances. Mitophagy is selective autophagy for clearing the damaged mitochondria and dysfunctional mitochondria. A myriad of evidence has demonstrated a major role of mitophagy in the regulation of type 2 diabetes and metabolic homeostasis. It is well established that defective mitophagy has been linked to the development of insulin resistance. Moreover, insulin resistance is further progressed to various diseases such as nephropathy, retinopathy and cardiovascular diseases. Concordantly, restoration of mitophagy will be a reliable and therapeutic target for type 2 diabetes. Recently, various phytochemicals have been proved to prevent dysfunctions of β-cells by mitophagy inductions during diabetes developments. In agreement with the above phenomenon, mitophagy inducers should be warranted as potential and novel therapeutic agents for treating diabetes. This review focuses on the role of mitophagy in type 2 diabetes relevant diseases and the pharmacological basis and therapeutic potential of autophagy regulators in type 2 diabetes.

Dietary Recommendations for Post-COVID-19 Syndrome

At the beginning of the coronavirus disease (COVID-19) pandemic, global efforts focused on containing the spread of the virus and avoiding contagion. Currently, it is evident that health professionals should deal with the overall health status of COVID-19 survivors. Indeed, novel findings have identified post-COVID-19 syndrome, which is characterized by malnutrition, loss of fat-free mass, and low-grade inflammation. In addition, the recovery might be complicated by persistent functional impairment (i.e., fatigue and muscle weakness, dysphagia, appetite loss, and taste/smell alterations) as well as psychological distress. Therefore, the appropriate evaluation of nutritional status (assessment of dietary intake, anthropometrics, and body composition) is one of the pillars in the management of these patients. On the other hand, personalized dietary recommendations represent the best strategy to ensure recovery. Therefore, this review aimed to collect available evidence on the role of nutrients and their supplementation in post-COVID-19 syndrome to provide a practical guideline to nutritionists to tailor dietary interventions for patients recovering from COVID-19 infections.

The effect of vitamin D supplementation on glycemic status of elderly people with prediabetes: a 12-month open-label, randomized-controlled study

BACKGROUND

Data on the efficacy of vitamin D in improving the glycemic status of elderly people with prediabetes are scarce. This open-label, randomized-controlled trial investigated the effect of vitamin D supplementation on glycemic markers of Greek people with prediabetes aged 60 years or above, over 12 months.

RESEARCH DESIGN AND METHODS

Participants were randomized to a weekly vitamin D₃ dose of 25,000 IU (n = 45) or nothing (n = 45), on top of lifestyle measures. Anthropometric and glycemic markers were assessed at baseline, 3, 6, and 12 months.

RESULTS

Supplemented participants demonstrated a significant increase in 25(OH)D concentrations at 3,      6,      and 12 months     compared to baseline    . In the intervention group, fasting glucose was decreased at 6 months compared to baseline (96.12 ± 5.51 vs 103.40 ± 12.05 mg/dl, p < 0.01) and glycated hemoglobin was significantly lower at 6 and 12 months compared to baseline [5.82 ± 0.21% vs 5.87 ± 0.21%, p = 0.004 and 5.80 ± 0.23% vs 5.87 ± 0.21%, p < 0.001, respectively].

CONCLUSIONS

Vitamin D could be complementary to lifestyle change strategy for the management of prediabetes in the elderly.

CLINICAL TRIAL REGISTRATION

ISRCTN51643592.

Old and Novel Therapeutic Approaches in the Management of Hyperglycemia, an Important Risk Factor for Atherosclerosis

Hyperglycemia is considered one of the main risk factors for atherosclerosis, since high glucose levels trigger multiple pathological processes, such as oxidative stress and hyperproduction of pro-inflammatory mediators, leading to endothelial dysfunction. In this context, recently approved drugs, such as glucagon-like-peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter-2 inhibitors (SGLT2i), could be considered a powerful tool for to reduce glucose concentration and cardiovascular risk. Interestingly, many patients with type 2 diabetes mellitus (T2DM) and insulin resistance have been found to be deficient in vitamin D. Recent studies pointed out the unfavorable prognostic values of T2DM and vitamin D deficiency in patients with cardiac dysfunction, either when considered individually or together, which shed light on the role of vitamin D in general health status. New evidence suggests that SGLT2i could adversely affect the production of vitamin D, thereby increasing the risk of fractures, which are common in patients with T2DM. Therefore, given the biological effects of vitamin D as an anti-inflammatory mediator and a regulator of endothelial function and calcium equilibrium, these new findings should be taken into consideration as well. The aim of this review is to gather the latest advancements regarding the use of antidiabetic and antiplatelet drugs coupled with vitamin D supplementation to control glucose levels, therefore reducing the risk of coronary artery disease (CAD).

A Narrative Review of the Evidence for Variations in Serum 25-Hydroxyvitamin D Concentration Thresholds for Optimal Health

Vitamin D3 has many important health benefits. Unfortunately, these benefits are not widely known among health care personnel and the general public. As a result, most of the world’s population has serum 25-hydroxyvitamin D (25(OH)D) concentrations far below optimal values. This narrative review examines the evidence for the major causes of death including cardiovascular disease, hypertension, cancer, type 2 diabetes mellitus, and COVID-19 with regard to sub-optimal 25(OH)D concentrations. Evidence for the beneficial effects comes from a variety of approaches including ecological and observational studies, studies of mechanisms, and Mendelian randomization studies. Although randomized controlled trials (RCTs) are generally considered the strongest form of evidence for pharmaceutical drugs, the study designs and the conduct of RCTs performed for vitamin D have mostly been flawed for the following reasons: they have been based on vitamin D dose rather than on baseline and achieved 25(OH)D concentrations; they have involved participants with 25(OH)D concentrations above the population mean; they have given low vitamin D doses; and they have permitted other sources of vitamin D. Thus, the strongest evidence generally comes from the other types of studies. The general finding is that optimal 25(OH)D concentrations to support health and wellbeing are above 30 ng/mL (75 nmol/L) for cardiovascular disease and all-cause mortality rate, whereas the thresholds for several other outcomes appear to range up to 40 or 50 ng/mL. The most efficient way to achieve these concentrations is through vitamin D supplementation. Although additional studies are warranted, raising serum 25(OH)D concentrations to optimal concentrations will result in a significant reduction in preventable illness and death.

The health effects of vitamin D supplementation: evidence from human studies

Vitamin D supplementation can prevent and cure nutritional rickets in infants and children. Preclinical and observational data suggest that the vitamin D endocrine system has a wide spectrum of skeletal and extra-skeletal activities. There is consensus that severe vitamin D deficiency (serum 25-hydroxyvitamin D (25OHD) concentration <30 nmol/l) should be corrected, whereas most guidelines recommend serum 25OHD concentrations of >50 nmol/l for optimal bone health in older adults. However, the causal link between vitamin D and many extra-skeletal outcomes remains unclear. The VITAL, ViDA and D2d randomized clinical trials (combined number of participants >30,000) indicated that vitamin D supplementation of vitamin D-replete adults (baseline serum 25OHD >50 nmol/l) does not prevent cancer, cardiovascular events, falls or progression to type 2 diabetes mellitus. Post hoc analysis has suggested some extra-skeletal benefits for individuals with vitamin D deficiency. Over 60 Mendelian randomization studies, designed to minimize bias from confounding, have evaluated the consequences of lifelong genetically lowered serum 25OHD concentrations on various outcomes and most studies have found null effects. Four Mendelian randomization studies found an increased risk of multiple sclerosis in individuals with genetically lowered serum 25OHD concentrations. In conclusion, supplementation of vitamin D-replete individuals does not provide demonstrable health benefits. This conclusion does not contradict older guidelines that severe vitamin D deficiency should be prevented or corrected.

Time out: should vitamin D dosing be based on patient's body mass index (BMI): a prospective controlled study

The recommended daily dose of vitamin D is 2000 IU was found to be insufficient in many patients. The objective of the present study is to find whether the daily dose of vitamin D should be based on BMI. Two hundred and thirty patients with an established vitamin D deficiency (serum level of 25 Hydroxy vitamin D3 (25OHD3) of ≤20 ng/ml) and patients with BMI ≥30 kg/m² were included in the study. Demographic data, comorbidities and BMI were recorded. Pre-treatment and post-treatment serum 25OHD3, calcium, phosphorus and parathyroid hormone (PTH) were tested at 0-, 3- and 6-month periods. Patients were treated with a standard dose of 50 000 IU of vitamin D weekly and 600/1200 mg of calcium a day. Once their level of 25OHD3 reached ≥30 ng/ml, patients were randomised into two groups. Group A received a standard recommended maintenance dose of 2000 IU daily and Group B patients received 125 IU/kg/m² of vitamin D3. The data were entered in the database and analysed. The mean age of Group A was 50⋅74 ± 7⋅64 years compared to 52⋅32 ± 7⋅21 years in Group B. In both groups, pre-treatment vitamin D level was ≤15 ng/ml and increased to 34⋅6 ± 2⋅6 and 33⋅7 ± 2⋅4 ng/ml at the end of 3 months treatment with a dose 50 000 IU of vitamin D3 and calcium 600/1200 mg once a day for group A and group B, respectively. At 6 months, patients in Group A 25OHD3 level was 22⋅8 ± 3⋅80 and in Group B was 34⋅0 ± 1⋅85 ng/ml (P < 0⋅001). This preliminary study suggests that obese patients need higher dosage of vitamin D than the recommended dose. It is prudent that the dosage should be based on the BMI to maintain normal levels for a healthy musculoskeletal system.

The peculiar role of vitamin D in the pathophysiology of cardiovascular and neurodegenerative diseases

Vitamin D is a hormone with both genomic and non-genomic actions. It exerts its activity by binding vitamin D receptor (VDR), which belongs to the superfamily of nuclear receptors and ligand-activated transcription factors. Since VDR has been found in various tissues, it has been estimated that it regulates approximately 3% of the human genome. Several recent studies have shown pleiotropic effects of vitamin D in various processes such as cellular proliferation, differentiation, DNA repair and apoptosis and its involvement in different pathophysiological conditions as inflammation, diabetes mellitus, and anemia. It has been suggested that vitamin D could play an important role in neurodegenerative and cardiovascular disorders. Moderate to strong associations between lower serum vitamin D concentrations and stroke and cardiovascular events have been identified in different analytic approaches, even after controlling for traditional demographic and lifestyle covariates. The mechanisms behind the associations between vitamin D and cerebrovascular and cardiologic profiles have been widely examined both in animal and human studies. Optimization of vitamin D levels in human subjects may improve insulin sensitivity and beta-cell function and lower levels of inflammatory markers. Moreover, it has been demonstrated that altered gene expression of VDR and 1,25D3-membrane-associated rapid response steroid-binding (1,25D3-MARRS) receptor influences the role of vitamin D within neurons and allows them to be more prone to degeneration. This review summarizes the current understanding of the molecular mechanisms underlying vitamin D signaling and the consequences of vitamin D deficiency in neurodegenerative and cardiovascular disorders.

Critical Appraisal of Large Vitamin D Randomized Controlled Trials

As a consequence of epidemiological studies showing significant associations of vitamin D deficiency with a variety of adverse extra-skeletal clinical outcomes including cardiovascular diseases, cancer, and mortality, large vitamin D randomized controlled trials (RCTs) have been designed and conducted over the last few years. The vast majority of these trials did not restrict their study populations to individuals with vitamin D deficiency, and some even allowed moderate vitamin D supplementation in the placebo groups. In these RCTs, there were no significant effects on the primary outcomes, including cancer, cardiovascular events, and mortality, but explorative outcome analyses and meta-analyses revealed indications for potential benefits such as reductions in cancer mortality or acute respiratory infections. Importantly, data from RCTs with relatively high doses of vitamin D supplementation did, by the vast majority, not show significant safety issues, except for trials in critically or severely ill patients or in those using very high intermittent vitamin D doses. The recent large vitamin D RCTs did not challenge the beneficial effects of vitamin D regarding rickets and osteomalacia, that therefore continue to provide the scientific basis for nutritional vitamin D guidelines and recommendations. There remains a great need to evaluate the effects of vitamin D treatment in populations with vitamin D deficiency or certain characteristics suggesting a high sensitivity to treatment. Outcomes and limitations of recently published large vitamin D RCTs must inform the design of future vitamin D or nutrition trials that should use more personalized approaches.

Vitamin D deficiency associations with metabolic, bone turnover and adverse general health markers in community free living adults

BACKGROUND

Although there is some evidence that vitamin D deficiency is highly prevalent in the Middle East, however its health impact is still not clear. The aim of this study was to assess the prevalence, causes and health implications of vitamin D deficiency in local United Arab Emirates (UAE) citizens.

METHODS

A cross-sectional study was conducted on community free living adults living in the city of Al Ain, UAE. Following informed written consent eligible subject's blood and urine samples were taken for measurements of vitamin D [25(OH)D], metabolic and bone turnover markers. Clinical assessment that includes general and self-rated health, muscle health, and physical activity were also performed.

RESULTS

A total of 648 subjects (491 female) were included in this analysis. Their mean (SD) age was 38 (12) years. Mean 25(OH)D was 24 ng/ml (range: 4-67) with 286 (44%) subjects found to have vitamin D deficiency (< 20 ng/ml), 234 (36%) subjects have insufficiency (20-32 ng/ml) and 128 (20%) subjects have optimal concentrations (> 32 ng/ml). 25(OH)D concentrations were significantly higher in local indigenous UAE subjects compared to other Arab expatriates (p = 0.071). Although there were no statistically significant differences in clinical markers between groups, however, utra-sensitive C-reactive protein (us-CRP), parathyroid hormone (PTH), body mass index (BMI) and the bone markers U-PYD and PYD/CR were higher in vitamin D deficient older subjects aged ≥50 years and female subjects younger than 50 years respectively compared to those with insufficiency or optimal concentrations (p value < 0.05. Multiple logistic regression analysis revealed significant and independent association between 25(OH)D status and age and sex (p < 0.05).

CONCLUSION

Older subjects with vitamin D deficiency have increased BMI, inflammation and PTH compared with those with insufficiency or optimal concentrations. Co-existence of obesity and vitamin D deficiency may have increased adverse health effects.

Vitamin D [25(OH)D] metabolites and epimers in obese subject: Interaction and correlations with adverse metabolic health risk factors

BACKGROUND

Although both vitamin D deficiency and obesity are highly prevalent in the UAE, the role of vitamin D metabolites in mediating obesity-related adverse health effects is not clear. We aimed to assess the role of vitamin D metabolites as potential mediators in the association between obesity, inflammation and metabolic risk factors.

METHODS

277 participants who were part of a randomized controlled trial had their assessment that included clinical, anthropometric and physical activity data at baseline and at 6 months. Blood and urine samples were taken for measurements of serum 25(OH)D, 25(OH)D metabolites including 25(OH)D3), 25(OH)D2), 1,25(OH)2D3, 3-Epi-D3), metabolic and inflammatory markers and related biochemical variables. Multiple regression analysis used to assess the role of 25(OH)D metabolites in mediating the effect of increasing body mass index (BMI) on inflammation and metabolic risk factors.

RESULTS

Overall, 277 participants with complete 6 months follow up with a mean (±SD) age of 41 ± 12 and 204 (74%) female were included in the study. Blood pressure, inflammatory, metabolic and lipid profile markers significantly increased in overweight and obese subjects compared to subjects with normal BMI both at baseline and at 6 months (p < 0.05). 25(OH)D revealed significant association with age, gender, HbA1c and type 2 diabetes (p < 0.05). No statistically significant changes in any of 25(OH)D metabolites assessed. Multivariate analysis revealed significant and independent associations between BMI and important inflammatory and metabolic risk factors (p < 0.05). No similar association observed with 25(OH)D metabolites.

CONCLUSION

Although we found significant association between 25(OH)D and prevalence of type 2 diabetes, we found no evidence however to support a role of 25(OH)D metabolites in mediating the effect of BMI on inflammatory or metabolic risk factors.

3. Prevention or Delay of Type 2 Diabetes and Associated Comorbidities: Standards of Medical Care in Diabetes-2022

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc22-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc22-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

5. Facilitating Behavior Change and Well-being to Improve Health Outcomes: Standards of Medical Care in Diabetes-2022

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc22-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc22-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Safety and tolerability of high-dose daily vitamin D3 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 D₃ in the vitamin D and type 2 diabetes (D2d) study.

SUBJECTS/METHODS

In total, 2423 overweight/obese persons with prediabetes were randomized in a double-blind manner to either 4000 IU of vitamin D₃ (the tolerable upper intake level for adults by the National Academy of Medicine) taken daily or matching placebo. All participants were included in this analysis. Incident adverse events (AE) were ascertained 4 times a year at in-person visits (twice a year) and interim remote encounters (twice a year) and were defined as untoward or unfavorable medical occurrences. Serious adverse events (SAE) included death, life-threatening events, and hospitalizations.

RESULTS

A total of 8304 AEs occurred during 3 years of follow-up and were less frequent in the vitamin D group compared to placebo (Incidence Rate Ratio [IRR] = 0.94; 95% Confidence Interval (CI) 0.90, 0.98). The overall frequency of protocol-specified AEs of interest, which included nephrolithiasis, hypercalcemia, hypercalciuria, or low estimated glomerular filtration rate, was low and did not differ by group. There were no significant between-group differences in total SAEs (IRR = 0.96 (0.81, 1.14)).

CONCLUSION

Vitamin D₃ supplementation at 4000 IU per day was safe and well tolerated among overweight/obese participants at high risk for diabetes who were appropriately monitored for safety. In this population, this dose of vitamin D₃ did not increase risk of AEs or SAEs, including those previously associated with vitamin D such as hypercalcemia, hypercalciuria, or nephrolithiasis.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT01942694, prospectively registered September 16, 2013.

Role of purinergic system and vitamin D in the anti-cancer immune response

For several years, scientists have recognized that vitamin D plays an important role in mineral and bone homeostasis. It was mostly used to treat osteoporosis and rickets in the past decades. Vitamin D has also been discovered to be modulator of the immune system and may play a role in a variety of diseases, including autoimmune diseases, in recent years. Vitamin D interaction with the vitamin D receptor (VDR), which has transcriptional imparts and is displayed on a variety of cell types, including those of the immune system, appears to be accountable for the immune-modulating effects. The action of tumor cells and vitamin D were the first to be investigated, but the spotlight is now on immunologic and purinergic systems. We conducted a systematic search in Pub Med as well as Google scholar for studies written in English. Vitamin D, cancer, purinergic signaling, and immune response were among the search words. Vitamin D has the potential to be a useful coadjuvant in cancer therapy and the purinergic system may be a potential treatment target to cancer therapy, according to our findings.

Dietary Magnesium Intake Affects the Association Between Serum Vitamin D and Type 2 Diabetes: A Cross-Sectional Study

Introduction: Circulating vitamin D concentrations have been associated with the risk of type 2 diabetes (T2D). Magnesium has also been reported to be associated with lower T2D risk. Besides, magnesium is an essential cofactor for vitamin D activation. However, the effect of dietary magnesium intake on the association between vitamin D and the risk of T2D has not been studied comprehensively. Therefore, we designed this cross-sectional study to assess the effect modification of magnesium intake on the association between vitamin D and risk of T2D.

Research Design and Methods: The present study analyzed data from the National Health and Nutrition Examination Survey (NHANES) continuously from 2007 to 2014, involving 10,249 participants. By having stratified participants based on magnesium intake category (low magnesium intake <267 mg/day; high magnesium intake: ≥267 mg/day), we further evaluated the difference (interaction test) between the relationship of vitamin D with the risk of T2D among low magnesium intake participants and high magnesium intake participants using weighted multivariable logistic regression.

Results: In this cross-sectional study, the association of serum vitamin D with the incidence of T2D appeared to differ between the low magnesium intake group and the high magnesium intake group (OR: 0.968, 95%Cl: 0.919–1.02 vs. OR: 0.925, 95%Cl: 0.883–0.97). Furthermore, there was evidence of interaction between vitamin D levels and magnesium intake on decreasing the incidence of T2D (p-value for interaction = 0.001).

Conclusions: The results of our study indicated that magnesium intake might affect the association of serum vitamin D with the risk of T2D. Such a finding requires further randomized controlled trials to provide more evidence.

Vitamin D is directly associated with favorable glycemic, lipid, and inflammatory profiles in individuals with at least one component of metabolic syndrome irrespective of total adiposity: Pró-Saúde Study, Brazil

Vitamin D insufficiency has been suggested as a risk factor for several metabolic disorders. The objective of the study was to investigate the association between serum 25 hydroxyvitamin D [25(OH)D] and metabolic health markers of Brazilian individuals with normal-weight, overweight or obesity. We hypothesized that serum 25(OH)D would be inversely associated with glycemic, lipid and inflammatory markers indicative of metabolic abnormality. Data of 511 individuals (33-79 years), recruited from a longitudinal investigation (Pró-Saúde Study), were analyzed cross-sectionally. Anthropometric, biochemical, body composition, socio-demographic and lifestyle data were collected. Based on body mass index (BMI; normal weight, overweight, obesity) and metabolic health (metabolically healthy (MH) and metabolically unhealthy (MU)) categories, the participants were classified into 6 phenotypes. Individuals having zero components of the metabolic syndrome were considered as "MH". MH obesity was frequent in 2.0% of the participants and 56.0% exhibited vitamin D insufficiency (<20 ng/mL). In the subgroups of the same BMI category, there were no significant differences in 25(OH)D concentrations between individuals classified as MH and MU. After adjustments (including %body fat and BMI), an inverse association was observed between 25(OH)D and visceral adipose tissue (B = -6.46, 95% confidence interval, CI: -12.87, -0.04), leptin (B = -0.09, 95% confidence interval, CI: -0.14, -0.03), insulin (B = -0.21, 95%CI: -0.34, -0.07), HOMA-IR (B = -0.06, 95%CI: -0.10, -0.02), triglycerides (B = -2.44, 95%CI: -3.66, -1.22), and TNF-α (B = -0.12, 95%CI: -0.24, -0.005) only in MU individuals. Our results indicate that the association of 25(OH)D concentrations with a favorable biochemical profile (glycemic, lipidic and inflammatory) seems to depend on the individual's overall metabolic health, suggesting more benefits from higher serum vitamin D in MU individuals, regardless of their adiposity.

Prevalence of vitamin D deficiency and its associated risk factors among rural population of the northern part of the Persian Gulf

BACKGROUND

Accumulating evidence indicates that vitamin D deficiency has been increased globally over the last two decades. However, the majority of these studies are concerned with cities and there is scant information regarding the prevalence of vitamin D in rural areas. The main aim of this study was to investigate the prevalence of vitamin D deficiency and its associated risk factors among the rural population in Bushehr province which shares the longest border with the Persian Gulf.

METHODS

The rural inhabitants of more than 25 years old from three mountainous, plain, and seashore areas of Bushehr province were selected through a stratified multi-cluster random sampling method. After obtaining the participants' demographic and anthropometric data and their past medical history, serum 25-hydroxyvitamin D [25(OH)D] was measured using ELISA.

RESULTS

A total of 1806 (means ±SD, 46± 14years old) rural subjects (35 % males and 65 % females) participated in this study. The prevalence of vitamin D deficiency, insufficiency, and sufficiency were 28 %, 50 %, and 22 %, respectively. The deficiency of vitamin D in women was higher than in men (OR=1.27, 95 % CI: 1.05 to 1.54, P=0.04). There was a positive significant correlation between age and serum vitamin D levels. Men with vitamin D deficiency had higher BMI (P=0.008); this association was not observed among women (P=0.7). There was no significant difference between the food item's consumption frequencies, and vitamin D status (P>0.05). The mountainous, and plain areas had the highest and lowest vitamin D levels, respectively.

CONCLUSIONS

Although, Bushehr province is located in a sunny part of Iran, the prevalence of vitamin D deficiency was high among its rural population. The shift of their lifestyle patterns and rapid industrialization in these rural areas may be responsible. Therefore, the enrichment of dietary sources with vitamin D and the use of vitamin D supplements are recommended to tackle the high prevalence of vitamin D deficiency in the rural population of the northern part of the Persian Gulf.

Vitamin D-independent benefits of safe sunlight exposure

This review examines the beneficial effects of ultraviolet radiation on systemic autoimmune diseases, including multiple sclerosis and type I diabetes, where the epidemiological evidence for the vitamin D-independent effects of sunlight is most apparent. Ultraviolet radiation, in addition to its role in the synthesis of vitamin D, stimulates anti-inflammatory pathways, alters the composition of dendritic cells, T cells, and T regulatory cells, and induces nitric oxide synthase and heme oxygenase metabolic pathways, which may directly or indirectly mitigate disease progression and susceptibility. Recent work has also explored how the immune-modulating functions of ultraviolet radiation affect type II diabetes, cancer, and the current global pandemic caused by SARS-CoV-2. These diseases are particularly important amidst global changes in lifestyle that result in unhealthy eating, increased sedentary habits, and alcohol and tobacco consumption. Compelling epidemiological data shows increased ultraviolet radiation associated with reduced rates of certain cancers, such as colorectal cancer, breast cancer, non-Hodgkins lymphoma, and ultraviolet radiation exposure correlated with susceptibility and mortality rates of COVID-19. Therefore, understanding the effects of ultraviolet radiation on both vitamin D-dependent and -independent pathways is necessary to understand how they influence the course of many human diseases.

Association Between Serum 25-hydroxyvitamin D Concentrations and Mortality Among Adults With Prediabetes

OBJECTIVES

To investigate the association of circulating 25-hydroxyvitamin D [25(OH)D] levels with mortality among adults with prediabetes.

METHODS

This retrospective cohort study included 15,195 adults with prediabetes (aged ≥20 years) from the National Health and Nutrition Examination Survey (NHANES) III and NHANES 2001-2014. Mortality from all causes, cardiovascular disease (CVD), and cancer was linked to National Death Index mortality data.

RESULTS

The median (interquartile range) concentration of serum 25(OH)D was 60.5 (45.3, 77.4) nmol/L, and only 23.1% had sufficient vitamin D (≥75 nmol/L). Elevated serum 25(OH)D concentrations were significantly associated with lower levels of insulin, homeostasis model assessment of insulin resistance, triglyceride, and C-reactive protein, and higher levels of high-density lipoprotein at baseline (all Ptrend < 0.05). During a median follow up of 10.7 years, 3765 deaths (including 1080 CVD deaths and 863 cancer deaths) were identified. Compared with participants with 25(OH)D <30 nmol/L, the multivariate-adjusted hazard ratios and 95% confidence intervals for participants with 25(OH)D ≥ 75 nmol/L were 0.66 (0.53, 0.82) for all-cause mortality (Ptrend < 0.001), 0.66 (0.48, 0.89) for CVD mortality (Ptrend = 0.001), and 0.82 (0.49, 1.35) for cancer mortality (Ptrend = 0.32). For per-unit increment in ln-transformed 25(OH)D, there was a 27% lower risk of all-cause mortality and a 34% lower risk of CVD mortality (both P < 0.01).

CONCLUSIONS

These findings suggested that higher serum 25(OH)D concentrations were associated with lower all-cause and CVD mortality among individuals with prediabetes.

Genetic Polymorphism of Vitamin D Family Genes CYP2R1, CYP24A1, and CYP27B1 Are Associated With a High Risk of Non-alcoholic Fatty Liver Disease: A Case-Control Study

Background

Previous studies have highlighted the important role of vitamin D and calcium pathway genes in immune modulation, cell differentiation and proliferation, and inflammation regulation, all closely implicated in the pathogenesis of non-alcoholic fatty liver disease (NAFLD).

Objective

This study aims to investigate whether 11 candidate single nucleotide polymorphisms (SNPs) in vitamin D and calcium pathway genes (CYP2R1, CYP24A1, and CYP27B1) are associated with the risk of NAFLD.

Methods

In this case-control study, a total of 3,023 subjects were enrolled, including 1,114 NAFLD cases and 1,909 controls. Eleven genetic variants in CYP2R1, CYP24A1, and CYP27B1 genes were genotyped. Logistic regression analysis was used to assess the effects of these variants on NAFLD risk. The functional annotations of positive SNPs were further evaluated by bioinformatics analysis.

Results

After adjusting for age, gender, and metabolic measures, we identified that CYP24A1 rs2296241 variant genotypes (recessive model: OR, 1.316; 95% CI, 1.048–1.653; p = 0.018), rs2248359 variant genotypes (recessive model: OR, 1.315; 95% CI, 1.033–1.674; p = 0.026), and CYP27B1 rs4646536 variant genotypes (additive model: OR, 1.147; 95% CI, 1.005–1.310; p = 0.042) were associated with an elevated risk of NAFLD. In combined effects analysis, we found that NAFLD risk significantly increased among patients carrying more rs2296241-A, rs2248359-T, and rs4646536-T alleles (p_trend = 0.049). Multivariate stepwise analysis indicated that age, visceral obesity, ALT, γ-GT, hypertriglyceridemia, hypertension, low HDL-C, hyperglycemia, and unfavorable alleles were independent predictors of NAFLD (all p < 0.05). The area under the receiver operating characteristic curve was 0.789 for all the above factors.

Conclusion

The polymorphisms of vitamin family genes CYP24A1 (rs2296241, CYP24A1, and rs2248359) and CYP27B1 (rs4646536) were associated with NAFLD risk in Chinese Han population, which might provide new insight into NAFLD pathogenesis and tools for screening high-risk population.

Vitamin D and acute and severe illness - a mechanistic and pharmacokinetic perspective

The COVID-19 pandemic has generated high interest in factors modulating risk of infection, disease severity and recovery. Vitamin D has received interest since it is known to modulate immune function and vitamin D deficiency is associated with increased risk of respiratory infections and adverse health outcomes in severely ill patients. There are no population representative data on the direct relationship between vitamin D status and SARS-CoV-2 infection risk and severity of COVID-19. Data from intervention studies are limited to 4 studies. Here we summarise findings regarding vitamin D status and metabolism and their alterations during severe illness, relevant to COVID-19 patients. Further, we summarise vitamin D intervention studies with respiratory disease outcomes and in critically ill patients and provide an overview of relevant patient and population guidelines. Vitamin D deficiency is highly prevalent in hospitalised patients, particularly when critically ill including those with COVID-19. Acute and critical illness leads to pronounced changes in vitamin D metabolism and status, suggestive of increased requirements. This needs to be considered in the interpretation of potential links between vitamin D status and disease risk and severity and for patient management. There is some evidence that vitamin D supplementation decreases the risk of respiratory tract infections, while supplementation of ICU patients has shown little effect on disease severity or length of treatment. Considering the high prevalence of deficiency and low risks associated with supplementation, pro-actively applying current population and patient management guidelines to prevent, monitor and correct vitamin D deficiency is appropriate.

Pharmacodynamics of Oral Cholecalciferol in Healthy Individuals with Vitamin D Deficiency: A Randomized Open-Label Study

Comparative pharmacodynamic (PD) analyses on different dosing schedules for cholecalciferol supplementation are limited. This was an open-label, randomized, parallel-group study involving 75 healthy individuals deficient in vitamin D (baseline 25OHD < 20 ng/mL) receiving oral cholecalciferol with three different dosing regimens: Group A: 10,000 IU/day for 8 weeks followed by 1000 IU/day for 4 weeks; Group B: 50,000 IU/week for 12 weeks and Group C: 100,000 IU every other week for 12 weeks. Regulators of calcium and phosphate homeostasis, bone turnover markers and Wnt inhibitors were measured at baseline, Day 28, 53, 84, and 112. The 1,25OH2D increased at each time point. The increase was greater (p < 0.05) for group A vs. B and C at Day 28, and vs. group B at Day 56. No significant difference among groups was observed for the other biomarkers. The 24,25OH2D remained stable over time. PTH decreased at Day 84 and FGF-23 increased at all time points. CTX-I and PINP increased slightly at Day 28. BALP decreased from Day 56 onward. Dkk-1 increased from Day 56 onward, while sclerostin did not show significant changes. In healthy individuals deficient in vitamin D, vitamin D supplementation exerted effects on multiple regulators of calcium, phosphate and bone metabolism, without marked differences using the three regimens.

Power determination in vitamin D randomised control trials and characterising factors affecting it through a novel simulation-based tool

Thousands of observational studies have linked vitamin D deficiency with numerous diseases, but randomised controlled trials (RCTs) often fail to show benefit of supplementation. Population characteristics and trial design have long been suspected to undermine power but were not systematically investigated. We propose a flexible generative model to characterise benefit of vitamin D supplementation at the individual level, and use this to quantify power in RCTs. The model can account for seasonality and population heterogeneity. In a simulated 1-year trial with 1000 participants per arm and assuming a 25-hydroxyvitamin D (25OHD) increase of 20 nmol/L due to the intervention, with baseline 25OHD in the population of 15, 35, 50, 60 and 75 nmol/L, the power to detect intervention effect was 77%, 99%, 95%, 68% and 19%, respectively. The number of participants required per arm to achieve 80% power according to baseline 25OHD of 15–60 nmol/L was 1200, 400, 600 and 1400, respectively. As expected, larger increases in 25OHD due to supplementation improved power in certain scenarios. For a population baseline of 50 nmol/L, with 1500 participants in each arm, there was 100% power to detect a 20 nmol/L 25OHD increase while it was 76% for a 10 nmol/L increase. Population characteristics and trial design, including temporal considerations, have a dramatic impact on power and required sample size in vitamin D RCTs.

Revisiting vitamin D status and supplementation for in-patients with intellectual and developmental disability in the North of England, UK

AIMS AND METHOD

To re-evaluate vitamin D testing and supplementation among in-patients with intellectual and developmental disability (IDD) and examine any correlates with physical health conditions, including COVID-19. Records of all in-patients between January 2019 and July 2020 (n = 78) were examined for 25-hydroxyvitamin D (25(OH)D) level, ward area, supplementation status, test seasonality, medication and health status.

RESULTS

The mean 25(OH)D level for supplemented (800 IU/day) patients was 75 nmol/L (s.d. = 20), compared with 40 nmol/L (s.d. = 19) in the non-supplemented group (P < 0.001). Thirty-eight percent of those who were in-patients during the first wave of the COVID-19 pandemic developed symptoms, but the small sample size could not establish vitamin D levels as a predictor of outcome.

CLINICAL IMPLICATIONS

Vitamin D (800 IU/day) supplementation is effective but the adequacy of the nationally recommended dose of 400 IU/day is unclear. Links to COVID-19 merit further research.

Adjunctive vitamin A and D for the glycaemic control in patients with concurrent type 2 diabetes and tuberculosis: a randomised controlled trial

The objective of this study is to investigate the effects of vitamin A, D and their interaction on the glycaemic control in patients with both diabetes and tuberculosis. Tuberculosis infection and its treatment induce hyperglycaemia and complicate the glycaemic control in patients with diabetes. A randomised controlled trial with a 2 × 2 factorial design was conducted in a tuberculosis-specialised hospital in Qingdao, China. A total of 279 patients who have both diabetes and tuberculosis were included in this analysis. The patients received standard anti-tuberculosis treatment alone (control group), or together with a dose of vitamin A (600 μg RAE/d) or vitamin D (10 μg/d) or a combination of vitamin A (600 μg RAE/d) and vitamin D (10 μg/d) for 2 months. The effects of the intervention on fasting plasma glucose and 2-h postprandial blood glucose were investigated by ANCOVA. The analysis was adjusted for baseline values, age, sex, smoking, drinking and antidiabetic treatment as covariates. No significant effect was observed for vitamin A and D supplementation on fasting plasma glucose, 2-h postprandial blood glucose, BMI and related blood parameters. No interaction was observed between vitamin A and D supplementation for these endpoints. Vitamin A and D supplementation showed a null effect on the glycaemic control for patients with concurrent diabetes and tuberculosis. Future work should evaluate the effect of vitamin A and D supplementation on insulin-related indices for these patients and investigate the effect of vitamin D receptor genotypes.

Effects of vitamin D3 on glucose metabolism in patients with severe osteoarthritis: A randomized double-blind trial comparing daily 2000 with 800 IU vitamin D3

AIM

To investigate the effect of daily 800 versus 2000 IU of vitamin D3 supplementation over 24 months on glycaemic control in older adults after unilateral knee replacement.

MATERIALS AND METHODS

The Zurich Multiple Endpoint Vitamin D Trial in Knee OA Patients was a randomized, double-blind trial conducted from 2008 to 2014 in Zurich, Switzerland. Participants were randomly allocated to 800 or 2000 IU vitamin D3 daily for 24 months. This study investigates the predefined secondary endpoints of fasting blood glucose (FBG) and homeostatic model assessment for insulin resistance (HOMA-IR) using linear mixed models adjusted for age, sex, baseline vitamin D deficiency and body mass index.

RESULTS

A total of 251 participants (age 70.2 ± 6.5 years; 55.4% women; 39% impaired glucose tolerance, mean 25-hydroxyvitamin D 27.48 ± 12.48 ng/mL, mean FBG 5.49 ± 0.71 mmol/L) were included in this analysis. There was no significant difference in FBG between the group receiving 800 versus 2000 IU after 2 years with a least square mean (95% CI) of 5.32 (5.19; 5.44) versus 5.39 (5.27; 5.51) mmol/L (p_treat = .130) and no difference in HOMA-IR (0.44 [0.37; 0.52] vs. 0.49 [0.41; 0.58]; p_treat = .162), respectively. However, FBG decreased significantly over time independent of vitamin D3 dose (800 IU: 5.54 [5.42; 5.66] to 5.32 [5.19; 5.44], p_time < .001; 2000 IU: 5.5 [5.38; 5.62] to 5.39 [5.27; 5.51] mmol/L, p_time = .019).

CONCLUSIONS

There was no clinically meaningful difference between 800 and 2000 IU of vitamin D3 over 2 years in FBG or HOMA-IR in community-dwelling older adults. Glycaemic outcomes improved in both groups.

Low 25-hydroxyvitamin D is associated with arterial stiffness in Chinese with Type 2 diabetes mellitus

OBJECTIVES

Arterial stiffness (AS), one of the complications of diabetes, associated with many metabolic factors. This study aimed to investigate the association between 25-hydroxyvitamin D(25(OH)D) and AS in type 2 diabetes mellitus (T2DM).

METHODS

We identified 1335 diabetic patients from the Department of Endocrinology, Shanghai Tenth People's Hospital. Finally, 603 T2DM patients were included in the study. They were divided into two groups: AS group (baPWV ≥ 15,500 cm/s) and the control group (baPWV < 1550 cm/s).

RESULTS

(1) Heart rate (HR) and systolic pressure (SBP) were higher while body weight and body mass index (BMI) were smaller in AS group than the control group (all P < 0.05). (2) Compared to patients without AS, patients with AS showed lower 25(OH)D and higher rate of 25(OH)D deficiency (42 ± 16 vs. 45 ± 17 mol/l, 68% vs. 64%, all P < 0.05). (3) BaPWV was negatively associated with 25(OH)D (r = -0.12, P = 0.004), while positively associated with age, duration of diabetes, HR, SBP, and low-density lipoprotein cholesterol and negatively associated with body weight and BMI (all P < 0.05). (4) Multiple linear regression showed that 25(OH)D was the negatively influencing factor of baPWV (β = -2.2, P = 0.01). Logistic regression showed that age and SBP were risk factor of AS (OR:1.07, 95% CI: 1.05-1.10, P < 0.001; OR:1.03, 95% CI: 1.02-1.04, P < 0.001) while 25(OH)D was protective factor of AS (OR:0.987, 95% CI: 0.976-0.998, P = 0.024).

CONCLUSIONS

T2DM patients with AS had lower 25(OH)D and higher rate of 25(OH)D deficiency. There was a negative relationship between 25(OH)D and AS assessed by baPWV.

New Roles for Vitamin D Superagonists: From COVID to Cancer

Vitamin D is a potent steroid hormone that induces widespread changes in gene expression and controls key biological pathways. Here we review pathophysiology of vitamin D with particular reference to COVID-19 and pancreatic cancer. Utility as a therapeutic agent is limited by hypercalcemic effects and attempts to circumvent this problem have used vitamin D superagonists, with increased efficacy and reduced calcemic effect. A further caveat is that vitamin D mediates multiple diverse effects. Some of these (anti-fibrosis) are likely beneficial in patients with COVID-19 and pancreatic cancer, whereas others (reduced immunity), may be beneficial through attenuation of the cytokine storm in patients with advanced COVID-19, but detrimental in pancreatic cancer. Vitamin D superagonists represent an untapped resource for development of effective therapeutic agents. However, to be successful this approach will require agonists with high cell-tissue specificity.