Effect of vitamin D deficiency in developed countries

A 12-week double-blind randomised controlled trial investigating the effect of dietary supplementation with 5000 μg/d (125 µg/d) vitamin D in adults with asthma

Vitamin D deficiency has previously been linked to higher rates of exacerbation and reduced lung function in asthmatics. Previous randomised controlled trials investigating the effect of vitamin D supplementation have mainly focused on children with asthma. Trials involving adults have typically used bolus dosing regimens, and the main outcomes have been patient-focused without investigating underlying inflammation. The present study aimed to conduct a 12-week placebo-controlled randomised controlled trials administering a daily 5000 μg (125 µg) vitamin D3 supplement to adults with mild to moderate asthma. A total of 32 participants were randomised to receive either the 5000 μg vitamin D3 supplement or an identical matching placebo. The primary outcome of the study was lung function measured by the ratio of FEV1:FVC (effect size 2·5) with secondary outcomes including asthma symptoms and inflammatory biomarkers. There was a small but statistically significant higher increase in the mean (±sd) ratio of FEV1:FVC from baseline to post-intervention in the vitamin D group (+0·05 ± 0·06) compared with the placebo group (+0·006 ± 0·04, P = 0·04). There was no effect of the intervention on asthma control test scores, or the inflammatory biomarkers measured. There was a moderate, significant association between baseline plasma 25(OH)D concentration and baseline plasma IL-10 (r = 0·527, P = 0·005) and TNF-α (r = −0·498. P = 0·008) concentrations. A daily vitamin D3 supplement led to slightly improved lung function in adult asthmatics and may be a useful adjunct to existing asthma control strategies, particularly for individuals with suboptimal vitamin D status.

Vitamin D Deficiency Leads to Poorer Health Outcomes and Greater Length of Stay After Total Knee Arthroplasty and Supplementation Improves Outcomes: A Systematic Review and Meta-Analysis

BACKGROUND

Vitamin D deficiency is increasingly identified as a predictor of poorer outcomes in musculoskeletal disease affecting as many as 1 in 4 people. This study aimed to evaluate the effect of vitamin D supplementation on outcomes after primary total knee arthroplasty (TKA).

METHODS

A targeted search of terms related to vitamin D and TKA outcomes was performed in PubMed, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, American Academy of Orthopaedic Surgeons, and British Orthopaedic Association databases. The results were analyzed using forest plots with I2 heterogeneity statistics and pooled effects with 95% confidence intervals (CIs) and p values. A p < 0.05 was considered statistically significant.

RESULTS

A total of 146,054 patients with 150,107 TKRs were analyzed in 10 studies that complied with the inclusion criteria, of which 3 were suitable for meta-analysis. Of these, 4 of the 10 studies showed that vitamin D deficiency resulted in poorer functional outcome scores (Western Ontario and McMasters Universities Osteoarthritis Index, Knee Society Scoring System, and American Knee Society scores), as well as increased risk of revision surgery, incidence of joint infection, and postoperative stiffness. Meta-analysis of length of hospital stay (LOS) demonstrated a significant increase in LOS in patients with vitamin D deficiency (standardized mean difference, -0.54, 95% CI, -0.69 to -0.38, p < 0.00001). Furthermore, outcomes were improved with vitamin D supplementation in 6 of 10 studies.

CONCLUSION

Vitamin D deficiency results in poorer outcomes of primary TKA, with improved outcomes after supplementation. Further studies should examine the role of preoperative vitamin D screening and/or perioperative supplementation in primary TKA and standardize outcome measures to assess their effect.

LEVEL OF EVIDENCE

Level I/II. See Instructions for Authors for a complete description of levels of evidence.

Vitamin D supplementation during pregnancy to prevent vitamin D deficiency in newborns: a systematic review and meta-analysis

Abstract Objectives: to assess the effects of vitamin D supplementation during pregnancy on the outcomes of vitamin D concentration in newborns, length at birth, overall health (Apgar), birth weight and maternal vitamin D concentration after childbirth. Methods: this research was conducted in the electronic databases of MEDLINE, LILACS, EMBASE and Cochrane Library until December 2020, using the terms “vitamin D”, “pregnancy”, “vitamin D deficiency”, “infant”, “newborn” and their synonyms. Randomized controlled trials were searched by evaluating the effects of maternal vitamin D supplementation in neonates. The data was analyzed on RevMan 5.4 software and the quality of evidence on GRADE. Results: the newborn’s overall health condition was presented as Apgar, with a mean difference (MD) of 0.15 (CI95%=0.06-0.25; p=0.002; I2=0%, two studies, 648 participants, moderate quality evidence) at the first minute and 0.11 (CI95%=0.04-0.17; p=0.001; I2=0%, two studies, 648 participants, moderate quality evidence) at the fifth minute. Significant effects were also presented at the length at birth considering any supplemented dose (MD=0.19; CI95%=0.08-0.30; p=0.0010; I2=0%, 1452 participants, low quality evidence) and birth weight in doses higher than 4000IU/day (MD=257.05 (CI95%=137.81-376.29; p<0.0001; I2=14%, 176 participants, moderate quality evidence). Conclusion: vitamin D supplementation during pregnancy improves serum 25 (OH) D concentration and suggests positive effects on overall health condition, length at birth and birth weight. PROSPERO CRD42017073292.

Autoimmune disease and interconnections with vitamin D

Vitamin D has well-documented effects on calcium homeostasis and bone metabolism but recent studies suggest a much broader role for this secosteroid in human health. Key components of the vitamin D system, notably the vitamin D receptor (VDR) and the vitamin D-activating enzyme (1α-hydroxylase), are present in a wide array of tissues, notably macrophages, dendritic cells and T lymphocytes (T cells) from the immune system. Thus, serum 25-hydroxyvitamin D (25D) can be converted to hormonal 1,25-dihydroxyvitamin D (1,25D) within immune cells, and then interact with VDR and promote transcriptional and epigenomic responses in the same or neighbouring cells. These intracrine and paracrine effects of 1,25D have been shown to drive antibacterial or antiviral innate responses, as well as to attenuate inflammatory T cell adaptive immunity. Beyond these mechanistic observations, association studies have reported the correlation between low serum 25D levels and the risk and severity of human immune disorders including autoimmune diseases such as inflammatory bowel disease, multiple sclerosis, type 1 diabetes and rheumatoid arthritis. The proposed explanation for this is that decreased availability of 25D compromises immune cell synthesis of 1,25D leading to impaired innate immunity and over-exuberant inflammatory adaptive immunity. The aim of the current review is to explore the mechanistic basis for immunomodulatory effects of 25D and 1,25D in greater detail with specific emphasis on how vitamin D-deficiency (low serum levels of 25D) may lead to dysregulation of macrophage, dendritic cell and T cell function and increase the risk of inflammatory autoimmune disease.

Science-based policy: targeted nutrition for all ages and the role of bioactives

Globally, there has been a marked increase in longevity, but it is also apparent that significant inequalities remain, especially the inequality related to insufficient 'health' to enjoy or at least survive those later years. The major causes include lack of access to proper nutrition and healthcare services, and often the basic information to make the personal decisions related to diet and healthcare options and opportunities. Proper nutrition can be the best predictor of a long healthy life expectancy and, conversely, when inadequate and/or improper a prognosticator of a sharply curtailed expectancy. There is a dichotomy in both developed and developing countries as their populations are experiencing the phenomenon of being 'over fed and under nourished', i.e., caloric/energy excess and lack of essential nutrients, leading to health deficiencies, skyrocketing global obesity rates, excess chronic diseases, and premature mortality. There is need for new and/or innovative approaches to promoting health as individuals' age, and for public health programs to be a proactive blessing and not an archaic status quo 'eat your vegetables' mandate. A framework for progress has been proposed and published by the World Health Organization in their Global Strategy and Action Plan on Ageing and Health (WHO (2017) Advancing the right to health: the vital role of law. https://apps.who.int/iris/bitstream/handle/10665/252815/9789241511384-eng.pdf?sequence=1&isAllowed=y . Accessed 07 Jun 2021; WHO (2020a) What is Health Promotion. www.who.int/healthpromotion/fact-sheet/en/ . Accessed 07 Jun 2021; WHO (2020b) NCD mortality and morbidity. www.who.int/gho/ncd/mortality_morbidity/en/ . Accessed 07 Jun 2021). Couple this WHO mandate with current academic research into the processes of ageing, and the ingredients or regimens that have shown benefit and/or promise of such benefits. Now is the time for public health policy to 'not let the perfect be the enemy of the good,' but to progressively make health-promoting nutrition recommendations.

Vitamin D and thyroid disorders: a systematic review and Meta-analysis of observational studies

BACKGROUND

The contribution of vitamin D to thyroid disorders has received paramount attention; however, results are mixed. Hence, we designed a systematic review and meta-analysis to obtain a definitive conclusion.

METHODS

The search included PubMed, ISI Web of Science, Scopus, and Google Scholar databases up to March 2021 to collect available papers reporting the relationship between serum levels of vitamin D and thyroid disorders. The pooled effect was reported as weighted mean difference (WMD) and 95% confidence interval (CI).

RESULTS

Out of 6123 datasets, 42 were eligible to get into this systematic review and meta-analysis. Serum vitamin D was markedly lower in autoimmune thyroid diseases (AITD) (WMD - 3.1 ng/dl; 95% CI, - 5.57 to - 0.66; P = 0.013; I² = 99.9%), Hashimoto's thyroiditis (HT) (WMD - 6.05 ng/dl; 95% CI, - 8.35 to - 3.75; P < 0.001; I² = 91.0%) and hypothyroidism patients (WMD - 13.43 ng/dl; 95% CI, - 26.04 to - 0.81; P = 0.03; I² = 99.5%), but not in subjects with Graves' disease (GD) (WMD - 4.14 ng/dl; 95% CI, - 8.46 to 0.17; P = 0.06; I² = 97.5%).

CONCLUSIONS

Our findings suggested lower vitamin D levels in patients with hypothyroidism, AITD, and HT compared to healthy subjects. However, the link between serum vitamin D and GD was only significant among subjects ≥40 years old.

Vitamin D Knowledge, Attitudes and Practices of Polish Medical Doctors

Background Vitamin D deficiency occurs in as much as 90-95% of the Polish population, although this condition is known to cause negative long-term health implications. The role of medical doctors in advising proper supplementation, monitoring and correcting the levels of 25-hydroxyvitamin D in individuals is of great importance and should be used to help mitigate its common deficits. The aim of this study was to evaluate knowledge, attitudes and practices of Polish physicians regarding vitamin D supplementation in order to identify areas for improvement and determinants for the knowledge gaps. Methods The study group comprised 701 medical doctors aged 32.1 ± 5.3 years on average, mostly women (71.61%). An original survey questionnaire was developed for the purpose of the study. Results The mean vitamin D knowledge score was 6.8 ± 2.3 (in a scale 0-13) and was related to gender (p < 0.001), type of specialization (p = 0.032), D3 supplements use (p < 0.001), recommending supplementation to patients (p = 0.005), to relatives and friends (p < 0.001) and to healthy adults (p < 0.001). In terms of self-administration, 14% of respondents take vitamin D all-year-round while 24% only in autumn and winter. 25% of respondents monitor their vitamin D (25-hydroxyvitamin D) serum concentration. Most participants (61%) did not recommend supplementing vitamin D to their patients on a regular basis. Conclusions The study indicates that medical doctors in Poland need to have more training and education on vitamin D supplementation in order to better address the problem of its deficits in the population.

Developing a Model for Prediction of Serum 25-Hydroxyvitamin D Level: The Use of Linear Regression and Machine Learning Methods

OBJECTIVE

Because vitamin D status affects many organs and tissues of the body, it is important to determine the factors affecting it. The purpose of this study was to develop a model for predicting the serum 25-hydroxyvitamin D [25(OH)D] level in healthy young adults.

METHOD

This cross-sectional study was conducted on 201 healthy individuals aged 20 to 40 years old in Shiraz, Iran. Data regarding demographic characteristics, vitamin D intake through supplements, and sun exposure habits were gathered. Serum 25(OH)D concentration was also measured. Data were analyzed with R software using linear regression and different machine learning methods such as conditional tree, conditional forest and random forest.

RESULTS

Based on the linear regression, male sex (p < 0.001), taking 50,000 IU vitamin D₃ supplement monthly (p < 0.001), and lower waist circumference (p = 0.018) were identified as effective factors in increasing serum 25(OH)D levels. According to the conditional tree, taking 50,000 IU vitamin D₃ supplement monthly (p < 0.001) and sex (p < 0.001) were two main factors in the classification of individuals in terms of serum 25(OH)D levels. Besides, conditional forest and random forest results showed that the most important variable was taking 50,000 IU vitamin D₃ supplement monthly.

CONCLUSIONS

Supplement use is the first and most important predictor of 25(OH)D levels and other factors, including sex and waist circumference, are ranked thereafter, and the importance of these factors is greater in those who do not take vitamin D₃ supplements.

The Role of Interferences in the Increasing Incidence of Vitamin D Deficiency

OBJECTIVE

Lipemia is one of the causes of interference in immunoassay and LC-MS/MS methods. Increased prevalence of vitamin D deficiency in the US, where obesity is gradually increasing, raises the suspicion that high levels of fat diet and blood lipid levels interfere with vitamin D measurement results. The focus of this study was to investigate the effect of blood lipid profiles on vitamin D results and prevent the matrix effect.

MATERIAL AND METHODS

In this study, 25OH vitamin D3 (25OHD3) levels of 100 samples consecutively accepted to biochemistry laboratory regardless of age and sex were measured by the LC-MS/MS method, and each sample was restudied after 1/10 dilution. After dilution restudy, two groups were obtained-group 1 (results deviating below 20%) and group 2 (results deviating above 20%)-and the difference between the groups was investigated. There were 79 patients in group 1 and 21 patients in group 2. In our study, lipid profiles (triglyceride, total cholesterol, HDL, LDL) from the same samples of consecutive vitamin D patients were studied.

RESULTS

It was observed that the triglyceride, total cholesterol HDL, LDL, and 25OHD3 measurements of group 1 and group 2 were similar (p > 0.05). While the mean vitamin D value in the second group was 9.94 ± 7.85, the mean vitamin D value after dilution was measured as 39.23 ± 18.13 and was statistically significant. 25OHD3 concentrations of 21 patients out of 100 were found to be falsely low. Measurements were repeated to confirm the results.

CONCLUSION

The matrix effect caused by exogenous and endogenous interferences in the blood could be a hidden factor increasing the prevalence of vitamin D deficiency by causing falsely low 25OHD3 values. Suspicious results should be remeasured by a dilution study.

The inter-relationship between marginal vitamin D deficiency and muscle

PURPOSE OF REVIEW

We review the recent literature on the interplay between mild vitamin D deficiency and skeletal muscle strength and performance.

RECENT FINDINGS

Preclinical studies indicate that vitamin D is important in muscle proliferation, differentiation and mitochondrial function, whereas some epidemiological studies demonstrate associations with muscle strength and low physical performance. Recent studies have implicated vitamin D deficiency in the development of frailty and sarcopenia in the older population. Some small studies have assessed its impact on muscle function in special circumstances such as elite sport and critical illness. Advances in liquid chromatography/mass spectrometry technologies have allowed the inter-relationships between the vitamin D metabolome and muscle phenotype to be characterized. There is evidence of distinct effects on human skeletal muscle gene expression between vitamin D metabolites.

SUMMARY

Large-scale clinical trials with well defined cohorts and outcomes are needed to provide clinically meaningful insights into this area. Care should be taken to stratify participants by vitamin D status at baseline and over follow-up in addition to observing a range of measures of muscle function.

Vitamin D Deficiency in the Gulf Cooperation Council: Exploring the Triad of Genetic Predisposition, the Gut Microbiome and the Immune System

Vitamin D is a fat soluble secosteroid that is primarily synthesized in the skin upon exposure to Ultraviolet B (UVB) sun rays. Vitamin D is essential for the growth and development of bones and helps in reducing inflammation by strengthening muscles and the immune system. Despite the endless supply of sunlight in the Gulf Cooperation Council (GCC) countries which includes United Arab Emirates, Qatar, Kuwait, Bahrain, Saudi Arabia, and Oman, Vitamin D deficiency in the (GCC) general population at various age groups remains alarmingly high. In parallel runs the increasing prevalence of acute and chronic illnesses including, autoimmune diseases, cancer, type 1 diabetes mellitus, cardiovascular disease and Inflammatory bowel disease in the adult as well as the pediatric population of these countries. The exact association between Vitamin D deficiency and chronic disease conditions remains unclear; however, studies have focused on the mechanism of Vitamin D regulation by assessing the role of the Vitamin D associated genes/proteins such as VDR (Vitamin D receptor), VDBP (Vitamin D Binding protein), CYP27B1 as these are integral parts of the Vitamin D signaling pathway. VDR is known to regulate the expression of more than 200 genes across a wide array of tissues in the human body and may play a role in controlling the Vitamin D levels. Moreover, reduced Vitamin D level and downregulation of VDR have been linked to gut dysbiosis, highlighting an intriguing role for the gut microbiome in the Vitamin D metabolism. However, this role is not fully described yet. In this review, we aim to expand our understanding of the causes of Vitamin D deficiency in the GCC countries and explore the potential relationship between the genetic predisposition, Vitamin D levels, immune system and the gut microbiome composition. Trying to unravel this complex interaction may aid in understanding the mechanism by which Vitamin D contributes to various disease conditions and will pave the way toward new therapeutics treatments for Vitamin D deficiency and its associated outcomes.

Frailty and the endocrine system

Frailty is a condition characterised by loss of biological reserves, failure of homoeostatic mechanisms, and vulnerability to adverse outcomes. The endocrine system is considered particularly important in frailty, because of its complex inter-relationships with the brain, immune system, and skeletal muscle. This Review summarises evidence indicating a key role for the hypothalamic-pituitary axis in the pathogenesis of frailty through aberrant regulation of glucocorticoid secretion, insulin-like growth factor signalling, and androgen production. Evidence also indicates a potential role for vitamin D and insulin resistance in the pathogenesis of frailty. The role of thyroid hormones in the pathogenesis of frailty remains uncertain. Key convergent pathological effects of frailty include loss of muscle mass and strength, with consequent impact on mobility and activities of daily living. Future translational research should focus on the understanding of endocrine mechanisms, to identify potential biomarkers of the condition, modifiable targets for treatment, and novel pharmacological drugs targeted at the endocrine components of frailty.