Randomized controlled trials of vitamin D and cancer incidence: A modeling study

Unveiling the Interplay-Vitamin D and ACE-2 Molecular Interactions in Mitigating Complications and Deaths from SARS-CoV-2

The interaction of the SARS-CoV-2 spike protein with membrane-bound angiotensin-converting enzyme-2 (ACE-2) receptors in epithelial cells facilitates viral entry into human cells. Despite this, ACE-2 exerts significant protective effects against coronaviruses by neutralizing viruses in circulation and mitigating inflammation. While SARS-CoV-2 reduces ACE-2 expression, vitamin D increases it, counteracting the virus's harmful effects. Vitamin D's beneficial actions are mediated through complex molecular mechanisms involving innate and adaptive immune systems. Meanwhile, vitamin D status [25(OH)D concentration] is inversely correlated with severity, complications, and mortality rates from COVID-19. This study explores mechanisms through which vitamin D inhibits SARS-CoV-2 replication, including the suppression of transcription enzymes, reduced inflammation and oxidative stress, and increased expression of neutralizing antibodies and antimicrobial peptides. Both hypovitaminosis D and SARS-CoV-2 elevate renin levels, the rate-limiting step in the renin-angiotensin-aldosterone system (RAS); it increases ACE-1 but reduces ACE-2 expression. This imbalance leads to elevated levels of the pro-inflammatory, pro-coagulatory, and vasoconstricting peptide angiotensin-II (Ang-II), leading to widespread inflammation. It also causes increased membrane permeability, allowing fluid and viruses to infiltrate soft tissues, lungs, and the vascular system. In contrast, sufficient vitamin D levels suppress renin expression, reducing RAS activity, lowering ACE-1, and increasing ACE-2 levels. ACE-2 cleaves Ang-II to generate Ang(1-7), a vasodilatory, anti-inflammatory, and anti-thrombotic peptide that mitigates oxidative stress and counteracts the harmful effects of SARS-CoV-2. Excess ACE-2 molecules spill into the bloodstream as soluble receptors, neutralizing and facilitating the destruction of the virus. These combined mechanisms reduce viral replication, load, and spread. Hence, vitamin D facilitates rapid recovery and minimizes transmission to others. Overall, vitamin D enhances the immune response and counteracts the pathological effects of SARS-CoV-2. Additionally, data suggests that widely used anti-hypertensive agents-angiotensin receptor blockers and ACE inhibitors-may lessen the adverse impacts of SARS-CoV-2, although they are less potent than vitamin D.

Physiology of Vitamin D-Focusing on Disease Prevention

Vitamin D is a crucial micronutrient, critical to human health, and influences many physiological processes. Oral and skin-derived vitamin D is hydroxylated to form calcifediol (25(OH)D) in the liver, then to 1,25(OH)2D (calcitriol) in the kidney. Alongside the parathyroid hormone, calcitriol regulates neuro-musculoskeletal activities by tightly controlling blood-ionized calcium concentrations through intestinal calcium absorption, renal tubular reabsorption, and skeletal mineralization. Beyond its classical roles, evidence underscores the impact of vitamin D on the prevention and reduction of the severity of diverse conditions such as cardiovascular and metabolic diseases, autoimmune disorders, infection, and cancer. Peripheral target cells, like immune cells, obtain vitamin D and 25(OH)D through concentration-dependent diffusion from the circulation. Calcitriol is synthesized intracellularly in these cells from these precursors, which is crucial for their protective physiological actions. Its deficiency exacerbates inflammation, oxidative stress, and increased susceptibility to metabolic disorders and infections; deficiency also causes premature deaths. Thus, maintaining optimal serum levels above 40 ng/mL is vital for health and disease prevention. However, achieving it requires several times more than the government's recommended vitamin D doses. Despite extensive published research, recommended daily intake and therapeutic serum 25(OH)D concentrations have lagged and are outdated, preventing people from benefiting. Evidence suggests that maintaining the 25(OH)D concentrations above 40 ng/mL with a range of 40-80 ng/mL in the population is optimal for disease prevention and reducing morbidities and mortality without adverse effects. The recommendation for individuals is to maintain serum 25(OH)D concentrations above 50 ng/mL (125 nmol/L) for optimal clinical outcomes. Insights from metabolomics, transcriptomics, and epigenetics offer promise for better clinical outcomes from vitamin D sufficiency. Given its broader positive impact on human health with minimal cost and little adverse effects, proactively integrating vitamin D assessment and supplementation into clinical practice promises significant benefits, including reduced healthcare costs. This review synthesized recent novel findings related to the physiology of vitamin D that have significant implications for disease prevention.

Infections and Autoimmunity-The Immune System and Vitamin D: A Systematic Review

Both 25-autoimmunity and(25(OH)D: calcifediol) and its active form, 1,25-dihydroxyvitamin D (1,25(OH)2D: calcitriol), play critical roles in protecting humans from invasive pathogens, reducing risks of autoimmunity, and maintaining health. Conversely, low 25(OH)D status increases susceptibility to infections and developing autoimmunity. This systematic review examines vitamin D's mechanisms and effects on enhancing innate and acquired immunity against microbes and preventing autoimmunity. The study evaluated the quality of evidence regarding biology, physiology, and aspects of human health on vitamin D related to infections and autoimmunity in peer-reviewed journal articles published in English. The search and analyses followed PRISMA guidelines. Data strongly suggested that maintaining serum 25(OH)D concentrations of more than 50 ng/mL is associated with significant risk reduction from viral and bacterial infections, sepsis, and autoimmunity. Most adequately powered, well-designed, randomized controlled trials with sufficient duration supported substantial benefits of vitamin D. Virtually all studies that failed to conclude benefits or were ambiguous had major study design errors. Treatment of vitamin D deficiency costs less than 0.01% of the cost of investigation of worsening comorbidities associated with hypovitaminosis D. Despite cost-benefits, the prevalence of vitamin D deficiency remains high worldwide. This was clear among those who died from COVID-19 in 2020/21-most had severe vitamin D deficiency. Yet, the lack of direction from health agencies and insurance companies on using vitamin D as an adjunct therapy is astonishing. Data confirmed that keeping an individual's serum 25(OH)D concentrations above 50 ng/mL (125 nmol/L) (and above 40 ng/mL in the population) reduces risks from community outbreaks, sepsis, and autoimmune disorders. Maintaining such concentrations in 97.5% of people is achievable through daily safe sun exposure (except in countries far from the equator during winter) or taking between 5000 and 8000 IU vitamin D supplements daily (average dose, for non-obese adults, ~70 to 90 IU/kg body weight). Those with gastrointestinal malabsorption, obesity, or on medications that increase the catabolism of vitamin D and a few other specific disorders require much higher intake. This systematic review evaluates non-classical actions of vitamin D, with particular emphasis on infection and autoimmunity related to the immune system.

Physiological Basis for Using Vitamin D to Improve Health

Vitamin D is essential for life-its sufficiency improves metabolism, hormonal release, immune functions, and maintaining health. Vitamin D deficiency increases the vulnerability and severity of type 2 diabetes, metabolic syndrome, cancer, obesity, and infections. The active enzyme that generates vitamin D [calcitriol: 1,25(OH)₂D], CYP27B1 (1α-hydoxylase), and its receptors (VDRs) are distributed ubiquitously in cells. Once calcitriol binds with VDRs, the complexes are translocated to the nucleus and interact with responsive elements, up- or down-regulating the expression of over 1200 genes and modulating metabolic and physiological functions. Administration of vitamin D₃ or correct metabolites at proper doses and frequency for longer periods would achieve the intended benefits. While various tissues have different thresholds for 25(OH)D concentrations, levels above 50 ng/mL are necessary to mitigate conditions such as infections/sepsis, cancer, and reduce premature deaths. Cholecalciferol (D₃) (not its metabolites) should be used to correct vitamin D deficiency and raise serum 25(OH)D to the target concentration. In contrast, calcifediol [25(OH)D] raises serum 25(OH)D concentrations rapidly and is the agent of choice in emergencies such as infections, for those who are in ICUs, and for insufficient hepatic 25-hydroxylase (CYP2R1) activity. In contrast, calcitriol is necessary to maintain serum-ionized calcium concentration in persons with advanced renal failure and hypoparathyroidism. Calcitriol is, however, ineffective in most other conditions, including infections, and as vitamin D replacement therapy. Considering the high costs and higher incidence of adverse effects due to narrow therapeutic margins (ED50), 1α-vitamin D analogs, such as 1α-(OH)D and 1,25(OH)₂D, should not be used for other conditions. Calcifediol analogs cost 20 times more than D₃-thus, they are not indicated as a routine vitamin D supplement for hypovitaminosis D, osteoporosis, or renal failure. Healthcare workers should resist accepting inappropriate promotions, such as calcifediol for chronic renal failure and calcitriol for osteoporosis or infections-there is no physiological rationale for doing so. Maintaining the population's vitamin D sufficiency (above 40 ng/mL) with vitamin D₃ supplements and/or daily sun exposure is the most cost-effective way to reduce chronic diseases and sepsis, overcome viral epidemics and pandemics, and reduce healthcare costs. Furthermore, vitamin D sufficiency improves overall health (hence reducing absenteeism), reduces the severity of chronic diseases such as metabolic and cardiovascular diseases and cancer, decreases all-cause mortality, and minimizes infection-related complications such as sepsis and COVID-19-related hospitalizations and deaths. Properly using vitamin D is the most cost-effective way to reduce chronic illnesses and healthcare costs: thus, it should be a part of routine clinical care.

Vitamin D in Cancer Prevention: Gaps in Current Knowledge and Room for Hope

Intensive epigenome and transcriptome analyses have unveiled numerous biological mechanisms, including the regulation of cell differentiation, proliferation, and induced apoptosis in neoplastic cells, as well as the modulation of the antineoplastic action of the immune system, which plausibly explains the observed population-based relationship between low vitamin D status and increased cancer risk. However, large randomized clinical trials involving cholecalciferol supplementation have so far failed to show the potential of such interventions in cancer prevention. In this article, we attempt to reconcile the supposed contradiction of these findings by undertaking a thorough review of the literature, including an assessment of the limitations in the design, conduct, and analysis of the studies conducted thus far. We examine the long-standing dilemma of whether the beneficial effects of vitamin D levels increase significantly above a critical threshold or if the conjecture is valid that an increase in available cholecalciferol translates directly into an increase in calcitriol activity. In addition, we try to shed light on the high interindividual epigenetic and transcriptomic variability in response to cholecalciferol supplementation. Moreover, we critically review the standards of interpretation of the available study results and propose criteria that could allow us to reach sound conclusions in this field. Finally, we advocate for options tailored to individual vitamin D needs, combined with a comprehensive intervention that favors prevention through a healthy environment and responsible health behaviors.

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.

Association between umbilical cord vitamin D levels and adverse neonatal outcomes

Objective

We investigated the associations between cord blood concentration of 25-hydroxyvitamin D [25(OH)D], neonatal outcomes, and the risk of hospitalization during the first year of life.

Methods

A total of 402 newborn infants and their mothers were prospectively enrolled and divided in four groups according to season of the year. We determined 25(OH)D serum concentrations from maternal–neonatal pairs at delivery by electrochemiluminescence immunoassay. Cut-offs at 25, 50, and 75 nmol/L defined vitamin D status, corresponding to deficiency, insufficiency, and sufficiency, respectively. Crude odds ratio (cOR) and 95% confidence intervals (CI) were estimated using logistic regression.

Results

Vitamin D severe deficiency (i.e., <25 nmol/L) was present in 18% of newborns. Cord blood severe deficiency was associated with an increased risk of preterm birth (cOR 3.6, 95% CI: 1.1–12.2), neonatal respiratory distress syndrome (cOR 5.9, 95% CI: 1.1–33.2), and increased risk of hospitalization during the first year of life because of acute respiratory infection (cOR 3.9, 95% CI: 1.4–10.6) or acute gastroenterocolitis (cOR 5.2, 95% CI: 1.4–19.1).

Conclusion

Cord blood vitamin D deficiency is associated with increased risk of preterm birth, neonatal respiratory distress syndrome, and hospitalization during the first year of life.

Arsenic trioxide-induced cell apoptosis and cell cycle arrest are potentiated by 1,25-dihydroxyvitamin D3 in human leukemia K562 cells

The interaction between 1,25-dihydroxyvitamin [1,25(OH)2D3] and vitamin D receptor (VDR) plays a critical role in regulating cell proliferation and programmed cell death. The present study aimed to investigate the effects of 1,25(OH)2D3 in combination with arsenic trioxide (As₂O₃) on the proliferation and cell cycle of a K562 leukemia cell line. K562 cells were treated with 100 nM 1,25(OH)2D3, 2.5 µM As₂O₃, and 100 nM 1,25(OH)2D3 combined with 2.5 µM As₂O₃. Cell proliferation was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt/phenazine ethosulfate method. Cell cycle progression and apoptosis were detected by flow cytometry. The expression levels of genes associated with the cell cycle and apoptosis were analyzed by reverse transcription-quantitative PCR and western blotting analyses. The present findings indicated that combined treatment of 1,25(OH)2D3 and As₂O₃ led to a significant increase in cytotoxicity, apoptotic cell death and G₁ cell cycle arrest when compared to those treated with 1,25(OH)2D3 or As₂O₃ alone. The downregulation of the Bax/Bcl-2 ratio and decreased survivin expression may be involved in combined treatment-mediated apoptosis. G₀/G₁ cell cycle arrest induced by combined treatment was associated with the activation of p21 and p27. In addition, the increased expression of VDR was found to participate in the anticancer effect of combination treatment. The data suggested that the combination of 1, 25-(OH)₂D₃ and As₂O₃ had clear synergistic effects on the inhibition of K562 cell proliferation, which could provide a novel therapeutic approach for the treatment of acute myeloid leukemia.

Zinc, ω-3 polyunsaturated fatty acids and vitamin D: An essential combination for prevention and treatment of cancers

Zinc, ω-3 polyunsaturated fatty acids (PUFAs) and vitamin D are essential nutrients for health, maturation and general wellbeing. Extensive literature searches have revealed the widespread similarity in molecular biological properties of zinc, ω-3 PUFAs and vitamin D, and their similar anti-cancer properties, even though they have different modes of action. These three nutrients are separately essential for good health, especially in the aged. Zinc, ω-3 PUFAs and vitamin D are inexpensive and safe as they are fundamentally natural and have the properties of correcting and inhibiting undesirable actions without disturbing the normal functions of cells or their extracellular environment. This review of the anticancer properties of zinc, ω-3 PUFAs and vitamin D is made in the context of the hallmarks of cancer. The anticancer properties of zinc, ω-3 PUFAs and vitamin D can therefore be used beneficially through combined treatment or supplementation. It is proposed that sufficiency of zinc, ω-3 PUFAs and vitamin D is a necessary requirement during chemotherapy treatment and that clinical trials can have questionable integrity if this sufficiency is not checked and maintained during efficacy trials.

Calcitriol Suppresses HIF-1 and HIF-2 Transcriptional Activity by Reducing HIF-1/2α Protein Levels via a VDR-Independent Mechanism

Hypoxia-inducible transcription factors 1 and 2 (HIFs) are major mediators of cancer development and progression and validated targets for cancer therapy. Although calcitriol, the biologically active metabolite of vitamin D, was attributed with anticancer properties, there is little information on the effect of calcitriol on HIFs and the mechanism underling this activity. Here, we demonstrate the negative effect of calcitriol on HIF-1/2α protein levels and HIF-1/2 transcriptional activity and elucidate the molecular mechanism of calcitriol action. We also reveal that the suppression of vitamin D receptor (VDR) expression by siRNA does not abrogate the negative regulation of HIF-1α and HIF-2α protein levels and HIF-1/2 transcriptional activity by calcitriol, thus testifying that the mechanism of these actions is VDR independent. At the same time, calcitriol significantly reduces the phosphorylation of Akt protein kinase and its downstream targets and suppresses HIF-1/2α protein synthesis by inhibiting HIF1A and EPAS1 (Endothelial PAS domain-containing protein 1) mRNA translation, without affecting their mRNA levels. On the basis of the acquired data, it can be proposed that calcitriol reduces HIF-1α and HIF-2α protein levels and inhibits HIF-1 and HIF-2 transcriptional activity by a VDR-independent, nongenomic mechanism that involves inhibition of PI3K/Akt signaling pathway and suppression of HIF1A and EPAS1 mRNA translation.

Vitamin D Levels in Patients with Colorectal Cancer Before and After Treatment Initiation

PURPOSE

We aimed to described 25-hydroxyvitamin D [25(OH)D] levels in newly diagnosed colorectal cancer (CRC) patients and to re-evaluate levels after chemotherapy.

METHODS

Permanent residents of the San Francisco Bay Area with a new CRC diagnosis of any stage were recruited prior to any non-surgical therapy. Serum 25(OH)D levels were measured at time of diagnosis and 6-month follow-up. Supplement use was not restricted. The primary endpoint was the frequency of vitamin D deficiency in patients with newly diagnosed CRC of all stages. The Kruskal-Wallis and Spearman correlation tests were used to evaluate associations of patient characteristics with 25(OH)D levels.

RESULTS

Median 25(OH)D level at baseline was 27.0 ng/mL (range 7.2, 59.0); 65% of patients had insufficient levels (25(OH)D < 30 ng/mL) (n = 94). Race, disease stage, multivitamin use, vitamin D supplementation, and county of residence were associated with baseline 25(OH)D levels (P < 0.05). The median change in 25(OH)D from baseline to 6 months was - 0.7 ng/mL [- 19.4, 51.7] for patients treated with chemotherapy (n = 58) and 1.6 ng/mL [- 6.4, 33.2] for patients who did not receive chemotherapy (n = 19) (P = 0.26). For patients who received vitamin D supplementation during chemotherapy, the median 25(OH)D change was 8.3 ng/mL [- 7.6, 51.7] versus - 1.6 [- 19.4, 24.3] for chemotherapy patients who did not take vitamin D supplements (P = 0.02).

CONCLUSION

Among patients with a new diagnosis of CRC, most patients were found to have 25(OH)D levels consistent with either deficiency or insufficiency. In the subset of patients who received chemotherapy and took a vitamin D supplement, serum 25(OH)D levels increased, suggesting that vitamin D repletion is a feasible intervention during chemotherapy.

Effect of Sunlight Exposure on Vitamin D Status of Individuals Living in a Nursing Home and Their Own Homes

INTRODUCTION/BACKGROUND

The present study was carried out to determine prevalence of vitamin D deficiency and related factors in individuals living in nursing home and their own homes.

METHODOLOGY

This cross-sectional study included 72 elderly people 60 yr and older. All subjects were given a questionnaire form evaluating their individual characteristics, eating habits which affected their vitamin D status, wearing habits, and their duration of sun exposure and a Standardized Mini Mental Test evaluating their cognitive levels. Serum 25(OH)D, calcium, parathyroid hormone, alkaline phosphatase and phosphorus levels, and bone mineral density measurements were also considered.

RESULTS

Vitamin D deficiency was observed in 47% of elderly people (nursing home: 64%, own home 31%, p = 0.05). Both 25(OH)D (14 ± 8 vs 27 ± 10, respectively, p < 0.001) and ultraviolet index value (0.63 ± 0.3 vs 0.92 ± 0.27, respectively, p < 0.001) were lower in people living in nursing home compared to ones living in their own homes. Parathyroid hormone level, on the other hand, was lower in people living in own homes. Vitamin D deficiency/insufficiency was more common in elderly people living in nursing home (100%) compared to those living in their own homes (64%) (p = 0.003). Osteopenia and osteoporosis incidence rates were also higher in elderly people living in nursing home (p = 0.001). No significant associations were found between vitamin D status and body mass index, smoking or dietary habits (p > 0.05). As levels of benefiting from ultraviolet index increased, significantly improvements were observed in 25(OH)D levels (p < 0.001).

CONCLUSIONS

In elderly people living in nursing home, vitamin D deficiency was higher and benefitting from ultraviolet index was lower compared to elderly people living in their own homes. Vitamin D deficiency could be prevented in elderly people, especially ones living in nursing homes, through enough sun exposure with appropriate clothing.

A Review of the Potential Benefits of Increasing Vitamin D Status in Mongolian Adults through Food Fortification and Vitamin D Supplementation

Serum 25-hydroxyvitamin D (25(OH)D) concentrations are low in Mongolia, averaging 22 ng/mL in summer and only 8 ng/mL in winter. Mongolians have high incidence and/or prevalence of several diseases linked to low 25(OH)D concentrations, including ischemic heart disease, malignant neoplasms, cirrhosis of the liver, ischemic stroke, lower respiratory tract infections, preterm birth complications, and diabetes mellitus. Fortifying regularly consumed foods such as flour, milk, and edible oils with vitamin D₃ could raise 25(OH)D concentrations by about 10 ng/mL. However, to achieve 25(OH)D concentrations of 30–40 ng/mL in adults, vitamin D intakes of 1000 to 4000 IU/day would be required, making personal supplement use necessary. On the basis of prospective observational studies and clinical trials of disease incidence or known mortality rates and adverse pregnancy and birth outcomes, raising mean serum 25(OH)D concentrations to 40 ng/mL would likely reduce incidence and mortality rates for those and other diseases, reduce the rate of adverse pregnancy and birth outcomes, and increase mean life expectancy by one year or more.

24R,25-dihydroxyvitamin D3 modulates tumorigenicity in breast cancer in an estrogen receptor-dependent manner

Vitamin D has long been prescribed as a supplement to breast cancer patients. This is partially motivated by data indicating that low serum vitamin D, measured as 25-hydroxyvitamin D3 [25(OH)D₃], is associated with worsened cancer prognosis and decreased survival rates in cancer patients. However, clinical studies investigating the role of vitamin D supplementation in breast cancer treatment are largely inconclusive. One reason for this may be that many of these studies ignore the complexity of the vitamin D metabolome and the effects of these metabolites at the cellular level. Once ingested, vitamin D is metabolized into 37 different metabolites, including 25(OH)D₃, which is the metabolite actually measured clinically, as well as 1,25(OH)₂D₃ and 24,25(OH)₂D₃. Recent work by our lab and others has demonstrated a role for 24R,25(OH)₂D₃, in the modulation of breast cancer tumors via an estrogen receptor α-dependent mechanism. This review highlights the importance of considering estrogen receptor status in vitamin d-associated prognostic studies of breast cancer and proposes a potential mechanism for 24R,25(OH)₂D₃ signaling in breast cancer cells.

Meteorological variables and the risk of fractures: A systematic review and meta-analysis

PURPOSE

The association between meteorological variables and risk of fractures has attracted increasing attentions but remain controversial. Therefore, our main aim is to clarify the association, and also to identify possible susceptible groups.

METHODS

Relevant literature was obtained through standard MeSH literature searching seven electronic databases. Because some studies expressed the association as the rate of incidence (IRR) of fractures associated with each 1 °C rise in temperature and 1% increase in relative humidity (RH), some expressed as IRR of fractures for the day with specific climatic variable versus control days, and also the association was expressed as correlations coefficients (COR) in some studies, separated meta-analyses were undertaken, with one based on IRR and another based on COR.

RESULTS

A total of 24 studies were included. Results showed that each 1 °C increase was significantly associated with a 3.0% decrease in fracture risk (IRR = 0.970, 95%CI: 0.952-0.988). The day with freezing rain and snow were associated with increased risk for both the lower extremity fracture (freezing rain: IRR = 1.174, 95%CI: 1.022-1.348; snow: IRR = 1.245, 95%CI: 1.050-1.477) and the upper extremity fracture (freezing rain: IRR = 1.376, 95%CI: 1.192-1.588; snow: IRR = 1.548, 95%CI: 1.361-1.761). No significant association was detected between RH, dew, frost, fog, storm and high wind, and fracture. The COR meta-analysis showed that mean temperature (moderately), maximum temperature (moderately), rainfall (weakly) and sunlight duration (weakly) were correlated with fracture occurrence.

CONCLUSION

The incidence of fractures was increased in lower temperature, the day with freezing rain, and snow. Other meteorological factors may have some effects on the incidence of fracture. The association maybe stronger for males, lower extremity fracture, and people living in Asia, subtropical zone, low-latitude, and northern hemisphere. Further studies are needed.

24R,25-Dihydroxyvitamin D3 regulates breast cancer cells in vitro and in vivo

BACKGROUND

Epidemiological studies indicate high serum 25(OH)D₃ is associated with increased survival in breast cancer patients. Pre-clinical studies attributed this to anti-tumorigenic properties of its metabolite 1α,25(OH)₂D₃. However, 1α,25(OH)₂D₃ is highly calcemic and thus has a narrow therapeutic window. Here we propose another metabolite, 24R,25(OH)₂D₃, as an alternative non-calcemic vitamin D₃ supplement.

METHODS

NOD-SCID-IL2γR null female mice with MCF7 breast cancer xenografts in the mammary fat pad were treated with 24R,25(OH)₂D₃ and changes in tumor burden and metastases were assessed. ERα66+ MCF7 and T47D cells, and ERα66- HCC38 cells were treated with 24R,25(OH)₂D₃in vitro to assess effects on proliferation and apoptosis. Effects on migration and metastatic markers were assessed in MCF7.

RESULTS

24R,25(OH)₂D₃ reduced MCF7 tumor growth and metastasis in vivo. In vitro results indicate that this was not due to an anti-proliferative effect; 24R,25(OH)₂D₃ stimulated DNA synthesis in MCF7 and T47D. In contrast, markers of invasion and metastasis were decreased. 24R,25(OH)₂D₃ caused dose-dependent increases in apoptosis in MCF7 and T47D, but not HCC38 cells. Inhibitors to palmitoylation, caveolae integrity, phospholipase-D, and estrogen receptors (ER) demonstrate that 24R,25(OH)₂D₃ acts on MCF7 cells through caveolae-associated, phospholipase D-dependent mechanisms via cross-talk with ERs.

CONCLUSION

These results indicate that 24R,25(OH)₂D₃ shows promise in treatment of breast cancer by stimulating tumor apoptosis and reducing metastasis.

GENERAL SIGNIFICANCE

24R,25(OH)₂D₃ regulates breast cancer cell survival through ER-associated mechanisms similar to 24R,25(OH)₂D₃ effects on chondrocytes. Thus, 24R,25(OH)₂D₃ may modulate cell survival in other estrogen-responsive cell types, and its therapeutic potential should be investigated in ER-associated pathologies.

Vitamin D and Gastrointestinal Cancers: A Narrative Review

Calcitriol (1,25(OH)₂D₃) performs various activities throughout the body. Although low serum 25-hydroxyvitamin D [25(OH)D] levels are associated with several disease processes such as risk of fractures and falls, hypertension, cardiovascular disease, and diabetes mellitus, recent evidence attests that this important hormone also regulates several cellular pathways involved in cancer development and progression. Calcitriol modulates several genes controlling gut physiology and calcium homeostasis and also maintains the integrity of epithelial barriers, regulates the absorption of phosphate and calcium, and modulates host defense against pathogens and inflammatory response by interplaying with several types of secretory and immune cells. Vitamin D deficiency is significantly related to increased risk of developing certain types of cancer. This deficiency can be prevented by vitamin D supplementation which is both economical and safe. This can lower the risk of developing cancer and also improve the prognosis of patients with gastrointestinal malignancy, but epidemiological data remain inconsistent. Several retrospective observational studies have demonstrated the benefits of vitamin D supplementation, but a few randomized controlled trials have not seemingly supported the beneficial role of vitamin D supplementation in gastrointestinal cancers. Therefore, in this literature review, we aimed to examine the possible role of vitamin D in gastrointestinal malignancies, including gastric, esophageal, pancreatic, hepatic, and colorectal cancers.

Vitamin D and health in the Mediterranean countries

Vitamin D, traditionally well known for its role in maintaining optimal health through its contribution to calcium metabolism and skeletal health, has received increased attention over the past two decades, with considerable focus being placed on its nonskeletal benefits. This paper is a narrative review of the nonskeletal health benefits of vitamin D, of particular interest to inhabitants of Mediterranean countries, namely, autism, cancer, cardiovascular disease, chronic obstructive pulmonary disease, dental caries, diabetes mellitus, erectile dysfunction, hypertension, metabolic syndrome, respiratory tract infections, all-cause mortality, and pregnancy and birth outcomes, because of the relatively high incidence and/or prevalence of these disorders in this region. Currently, the best evidence is coming out of observational studies related to serum 25-hydroxyvitamin D [25(OH)D] concentrations. Vitamin D clinical trials have generally been poorly designed and conducted, usually being based on vitamin D dose rather than 25(OH)D concentration. The optimal 25(OH)D concentration is above 75 nmol/l (30 ng/ml), with even better health outcomes in the range of 100-150 nmol/l. Achieving these concentrations with vitamin D₃ supplements will require 1000-4000 IU/day of vitamin D₃. Sensible sun exposure should also be encouraged. Countries should also consider fortifying grain and dairy products with vitamin D₃.

A randomized placebo-controlled trial of vitamin D supplementation for reduction of mortality and cancer: Statistical analysis plan for the D-Health Trial

Background

Many observational studies have reported an association between vitamin D and non-skeletal health outcomes. The D-Health Trial was launched to determine if supplementing the older population with high monthly doses of Vitamin D can prevent cancer and premature mortality. The intervention is ongoing but here we provide a detailed statistical analysis plan for the primary and secondary outcomes of the D-Health Trial.

Methods/design

The D-Health Trial is a double-blind, randomized, placebo-controlled trial. Between February 2014 and May 2015, 21,315 people were randomized in a 1:1 ratio to receive monthly doses of either 60,000 IU of cholecalciferol (vitamin D₃) or placebo for five years. The primary outcome is all-cause mortality and the secondary outcomes are total cancer incidence and colorectal cancer incidence. These will be ascertained via linkage to death and cancer registries. The primary analysis for each outcome will follow an intention-to-treat approach; we will use flexible parametric survival models to investigate the association between supplementation and time to an event. We describe in detail sophisticated secondary analyses that consider non-compliance and contamination due to off-study supplementation.

Conclusions

Publication of this statistical analysis plan in advance of the intervention's completion, and adherence to it, will avoid data-driven analyses of the primary and secondary outcomes and ensure robust reporting of outcomes.

Clinical trial registration number

Australian New Zealand Clinical Trials Registry: ACTRN12613000743763. Registered on 4 July 2013.

Vitamin D testing and treatment: a narrative review of current evidence

Vitamin D testing and treatment is a subject of controversial scientific discussions, and it is challenging to navigate through the expanding vitamin D literature with heterogeneous and partially opposed opinions and recommendations. In this narrative review, we aim to provide an update on vitamin D guidelines and the current evidence on the role of vitamin D for human health with its subsequent implications for patient care and public health issues. Vitamin D is critical for bone and mineral metabolism, and it is established that vitamin D deficiency can cause rickets and osteomalacia. While many guidelines recommend target serum 25-hydroxyvitamin D (25[OH]D) concentrations of ≥50 nmol/L (20 ng/mL), the minimum consensus in the scientific community is that serum 25(OH)D concentrations below 25-30 nmol/L (10-12 ng/mL) must be prevented and treated. Using this latter threshold of serum 25(OH)D concentrations, it has been documented that there is a high worldwide prevalence of vitamin D deficiency that may require public health actions such as vitamin D food fortification. On the other hand, there is also reason for concern that an exploding rate of vitamin D testing and supplementation increases costs and might potentially be harmful. In the scientific debate on vitamin D, we should consider that nutrient trials differ from drug trials and that apart from the opposed positions regarding indications for vitamin D treatment we still have to better characterize the precise role of vitamin D for human health.

Plasma 25-hydroxyvitamin D concentrations and risk of incident cancer in adults with hypertension: A nested case-control study

BACKGROUND & AIMS

Evidence from epidemiologic studies on the association of circulating 25-hydroxyvitamin D [25(OH)D] concentrations with the incident risk of cancer has been inconsistent. We aimed to investigate the prospective relationship of baseline plasma 25(OH)D concentrations with the risk of cancer, and to examine possible effect modifiers.

METHODS

We employed a nested case-control study design, including 231 patients with incident cancer during a median 4.5 years of follow up, and 231 matched controls from the China Stroke Primary Prevention Trial (CSPPT).

RESULTS

The prevalence of plasma 25(OH)D <15, <20 and <30 ng/mL was 23.6%, 47.4% and 85.5%, respectively. Overall, there was an inverse relation between risk of cancer and plasma 25(OH)D. The Odds ratios (95% CI) for participants in the second (15.1 to <20.6 ng/mL), third (20.6 to <26.4 ng/mL) and fourth quartiles (≥26.4 ng/mL) were 0.45 (95% CI: 0.25-0.80), 0.53 (95% CI: 0.27-1.06) and 0.55 (95% CI: 0.27-1.10), respectively, compared with those in quartile 1. Conversely, low 25(OH)D (<15.1 ng/mL) concentrations were associated with increased risk of cancer (OR, 2.08; 95% CI: 1.20-3.59) compared to higher concentrations. These associations were consistent across subtypes of cancer. Several potential effect modifiers were identified, including plasma vitamin E concentrations and alcohol intake.

CONCLUSIONS

Low plasma 25(OH)D concentrations (<15.1 ng/mL) were associated with increased total cancer risk among Chinese hypertensive adults, compared to higher 25(OH)D concentrations. This finding and the possible effect modifiers warrant additional investigation.

Are the protective benefits of vitamin D in neurodegenerative disease dependent on route of administration? A systematic review

Background: The clinical and preclinical exploration of the therapeutic properties of vitamin D have significantly increased in the past decade, owing to the growing associative evidence suggesting vitamin D is neuroprotective. However, whether depletion of vitamin D contributes to the onset of neurological disorders or is a symptom of neurological disease has yet to be defined. Much remains unclear about the causal role of vitamin D and the method of use and forms of vitamin D.Objectives: We sought to quantitatively assess if neuroprotective benefits from vitamin D in neurodegenerative diseases are dependent on route of administration: comparing the effect of endogenously sourced vitamin D from UV exposure to exogenously derived vitamin D through synthetic supplementation.Design: We systematically searched PubMed, Embase and PsycInfo databases which included both pre-clinical and clinical studies investigating vitamin D in neurodegenerative diseases. Articles were subject to strict inclusion criteria and objectively assessed for quality. Additionally, Medline data was analysed to identify trends in topic publications and linguistic characteristics of papers.Results: From a total of 231 screened articles, we identified 73 appropriate for review based on inclusion criteria: original studies that investigated vitamin D levels or levels of vitamin D supplementation in neurodegenerative diseases or investigated past/present sun exposure in disease cohorts. Results indicate there is insufficient evidence to comprehensively reflect on a potential neuroprotective role for vitamin D and if this was dependent on route of administration. The majority of current data supporting neuroprotective benefits from vitamin D are based on pre-clinical and observational studies. Solid evidence is lacking to support the current hypothesis that the beneficial effect of UV exposure results from the synthesis of vitamin D. Sun exposure, independent of vitamin D production, may be protective against multiple Sclerosis, Parkinson's disease and Alzheimer's disease. Yet, further research is required to elucidate the beneficial mechanism of actions of UV exposure. The literature of vitamin D and amyotrophic lateral sclerosis was limited, and no conclusions were drawn. Therefore, in cases where UV-derived vitamin D was hypothesized to be the beneficial mediator in the neuroprotective effects of sun exposure, we propose results are based only on associative evidence.Conclusion: On the basis of this systematic review, strong recommendations regarding therapeutic benefits of vitamin D in neurodegenerative disease cannot be made. It is unclear if vitamin D mediates a protective benefit in neurodegenerative disease or whether it is an associative marker of UV exposure, which may contribute to as of yet unidentified neuroprotective factors.

Efficacy of Vitamin D interventional strategies in saudi children and adults

Despite the amount of sunshine in Saudi Arabia, vitamin D (25(OH)D) deficiency is highly prevalent among Saudis. Several strategies are known to improve 25(OH)D status. The aim of this study was to evaluate the efficacy of different interventional strategies in improving 25(OH)D status in Saudi children and adults. This interventional study was undertaken among 593 out of 1152 Saudi subjects [530 students (aged 13-17 years) and 63 teachers (aged 26-46 years)] over a 6-month period from different secondary schools in Riyadh, Saudi Arabia. 25(OH)D status was taken at baseline and after 6 months post interventions. Subjects were divided into 3 groups and requested to implement different vitamin D correction schemes: sun-exposure, vitamin D-fortified milk consumption, and oral vitamin D supplementation (1000IU/day). Follow-up results revealed that all correction strategies used could decrease the deficiency of serum 25(OH)D with different potencies, with the highest positive percentage change observed in oral supplementation in both adults and children (11% men, 17% women, 16% boys and 8% girls). The oral vitamin D supplementation strategy also showed significant positive associations between delta (Δ) changes and HDL-cholesterol in both adults and children. In conclusion, oral vitamin D supplementation was the most effective strategy in improving vitamin D status in Saudi adults and children than sunlight exposure or consumption of vitamin D-fortified dairy products.

Annual Ambient UVB at Wavelengths that Induce Vitamin D Synthesis is Associated with Reduced Esophageal and Gastric Cancer Risk: A Nested Case-Control Study

Vitamin D has been shown to be beneficial at reducing the risk of cancer; however, studies examining esophageal and gastric cancer have been scarce and findings inconsistent. The UK Biobank cohort was used for this nested case-control study (N = 3732). Primary, incident esophageal and gastric cancer cases diagnosed after recruitment were identified via linkage to National Cancer Registries. Tropospheric Emissions Monitoring Internet Service database was used to calculate ambient annual UVB dose (D-UVB). Conditional logistic regression was used to investigate the relationship between annual ambient D-UVB and risk of esophageal and gastric cancer, and odds ratios (ORs) are reported. In total, 373 esophageal and 249 gastric cancer cases and 3110 age- and gender-matched controls were included in the study. We found a strong inverse association between annual ambient D-UVB and odds of developing esophageal or gastric cancer: Compared to the lowest tertile, OR for the highest tertile was 0.64 (95%CI:0.51-0.79) in adjusted analysis. The association was strengthened when restricted to esophageal cancer (OR = 0.60; 95%CI:0.45-0.80) and esophageal adenocarcinoma cases (OR = 0.48; 95%CI: 0.34-0.68). Similar results were found in unadjusted and stratified analysis. In conclusion, ambient UVB radiation is inversely associated with the development of esophageal and gastric cancer, even in a high-latitude country.

Why vitamin D clinical trials should be based on 25-hydroxyvitamin D concentrations

Many health benefits are attributed to vitamin D, with those findings supported mostly by observational outcome studies of relationships to serum 25-hydroxyvitamin D [25(OH)D]. However, many randomized controlled trials (RCTs) aiming to confirm those findings have failed, perhaps because serum 25(OH)D is an index of UVB exposure and non-vitamin D mechanisms or because disease reduces serum 25(OH)D content. But the most likely reason for that failure is inappropriate design, conduct, analysis, and interpretation of RCTs. Most RCTs used principles designed to test pharmaceutical drugs; that design incorporates the assumptions that the RCT is the sole source of the agent and that dose-response relationships are linear. However, neither assumption is true for vitamin D, since neither vitamin D dose-responses or health outcome-serum 25(OH)D concentration relationships are linear-larger changes being induced with low rather than high baseline 25(OH)D values. Here, we propose a hybrid observational approach to vitamin D RCT design, based primarily on serum 25(OH)D concentration, requiring an understanding of serum 25(OH)D concentration-health outcome relationships, measuring baseline 25(OH)D values, recruiting non-replete subjects, measuring serum 25(OH)D during the trial for adjustment of supplemental doses for achievement of pretrial selection of target 25(OH)D values, where possible, and analyzing health outcomes in relation to those data rather than solely to vitamin D dosages.

Vitamin D Supplementation Guidelines for General Population and Groups at Risk of Vitamin D Deficiency in Poland-Recommendations of the Polish Society of Pediatric Endocrinology and Diabetes and the Expert Panel With Participation of National Specialist Consultants and Representatives of Scientific Societies-2018 Update

INTRODUCTION

Vitamin D deficiency is an important public health problem worldwide. Vitamin D deficiency confers a significant risk for both skeletal and non-skeletal disorders and a number of lifelong negative health outcomes. The objectives of this evidence-based guidelines document are to provide health care professionals in Poland, an updated recommendation for the prevention, diagnosis and treatment of vitamin D deficiency.

METHODS

A systematic literature search examining the prevention and treatment strategies for vitamin D deficiency was conducted. Updated recommendations were developed using the Grading of Recommendations, Assessment, Development and Evaluation system describing the strength of the recommendation and the quality of supporting evidence. Twenty-seven contributors representing different areas of expertise and medical specialties, including pediatricians, geriatricians, endocrinologists, epidemiologists, nephrologists, gynecologists and obstetricians evaluated the available published evidence related to vitamin D, formulated the goals of this document and developed a common consolidated position. The consensus group, representing six national specialist consultants and eight Polish and international scientific organizations/societies, participated in the process of grading evidence and drawing up the general and specific recommendations.

RESULTS

The updated recommendations define the diagnostic criteria for the evaluation of vitamin D status and describe the prevention and treatment strategies of vitamin D deficiency in the general population and in groups at increased risk of the deficiency. Age- and weight-specific recommendations for prevention, supplementation and treatment of vitamin D deficiency are presented, and detailed practice guidance is discussed regarding the management in primary and specialized health care.

CONCLUSION

Vitamin D deficiency remains still highly prevalent in Poland, in all age groups. Currently, there is a great necessity to implement a regular supplementation with recommended doses and to develop an effective strategy to alleviate vitamin D deficiency in the population. These updated recommendations are addressed to health professionals and the authorities pursuing comprehensive health policies and should also be included in public health programs aimed at preventing a broad spectrum of chronic diseases.

Vitamin D and Breast Cancer: Latest Evidence and Future Steps

Vitamin D (the sunshine vitamin) plays a vital role in calcium homeostasis, skeletal metabolism, and immune, cardiovascular, and reproductive systems’ functions. The worldwide prevalence of vitamin D deficiency is approximately 1 billion. Vitamin D deficiency is a serious health problem with numerous health consequences; it is associated with diabetes, rheumatic arthritis, Parkinson, Alzheimer diseases, osteomalacia, osteoporosis, and fractures in adults and cancers. Many reports showed an inverse association between serum vitamin D concentration and incidence of several cancers, including breast, colorectal, kidney, lung, and pancreatic. About 20 different cancers have incidence rates inversely related to solar UV-B doses and serum vitamin D concentration. Considering the rising incidence of breast cancer and high prevalence of vitamin D deficiency, this review aimed to reflect an association between serum vitamin D concentration and breast cancer risk, reveal the link between vitamin D receptor genetic polymorphisms and breast cancer risk, and review the relationship between vitamin D level, breast cancer risk, and prognostic factors such as tumor stage, grade, size, lymph node involvement, and hormone receptor status.

Vitamin D deficiency was common among nursing home residents and associated with dementia: a cross sectional study of 545 Swedish nursing home residents

Background

Residents of nursing homes may have low 25-hydroxyvitamin D (25OHD) concentrations. Associations between vitamin D and cognitive performance, dementia and susceptibility to infections are not clearly established. The aim of this study was to investigate the prevalence of vitamin D deficiency and to identify associated factors among residents of nursing homes for elderly.

Methods

In this cross-sectional study blood samples for analysis of 25OHD were collected from all participating residents of Swedish nursing homes for the elderly from January to March 2012.

Exclusion criteria: dementia too severe to collect a blood test, terminally ill or refusing participation. Outcome Measures: Serum 25OHD concentrations. Logistic regression to evaluate factors associated with vitamin D deficiency (25OHD < 25 nmol/L).

Results

Blood samples were obtained from 545 of 901 residents of 22 nursing homes. Mean age 86 years (SD 6.9), 68% were women. Prevalence of vitamin D supplementation 17%, dementia 55%, lack of appetite ≥3 months 45% and any antibiotic treatment during the last 6 months 30%. Serum 25OHD concentrations: mean 34 nmol/L (SD 21, median 27, range 4–125), 82% (448/545) had 25OHD < 50 nmol/L and 41% (224/545) had 25OHD < 25 nmol/L. Adjusted OR (95% CI; p-value) for possible predictors of vitamin D deficiency (25OHD < 25 nmol/L): vitamin D supplementation 0.075 (0.031–0.18; p < 0.001), lack of appetite ≥3 months 0.75 (0.50–1.1; p = 0.15), hours outdoors/week 0.99 (0.96–1.0; p = 0.62), Fitzpatrick skin phototype (4–6) 0.69 (0.44–1.1; p = 0.12); dementia 2.3 (1.5–3.4; p < 0.001) and antibiotics last 6 months 1.6 (1.1–2.6; p < 0.029), adjusted for age and gender.

Conclusions

Vitamin D deficiency was common among nursing home residents and strongly associated with dementia. Regardless of causality or not, it is important to be alert for vitamin D deficiency in nursing homes residents with dementia. As expected vitamin D supplementation was associated with less vitamin D deficiency, however lack of appetite, staying outdoors and skin phototype were not significant predictors. Antibiotic treatments during the last 6 months were associated with vitamin D deficiency, potentially supporting the hypothesis that vitamin D deficiency is associated with infections.

Non-skeletal health effects of vitamin D supplementation: A systematic review on findings from meta-analyses summarizing trial data

BACKGROUND

A large number of observational studies have reported harmful effects of low 25-hydroxyvitamin D (25OHD) levels on non-skeletal outcomes. We performed a systematic quantitative review on characteristics of randomized clinical trials (RCTs) included in meta-analyses (MAs) on non-skeletal effects of vitamin D supplementation.

METHODS AND FINDINGS

We identified systematic reviews (SR) reporting summary data in terms of MAs of RCTs on selected non-skeletal outcomes. For each outcome, we summarized the results from available SRs and scrutinized included RCTs for a number of predefined characteristics. We identified 54 SRs including data from 210 RCTs. Most MAs as well as the individual RCTs reported null-findings on risk of cardiovascular diseases, type 2 diabetes, weight-loss, and malignant diseases. Beneficial effects of vitamin D supplementation was reported in 1 of 4 MAs on depression, 2 of 9 MAs on blood pressure, 3 of 7 MAs on respiratory tract infections, and 8 of 12 MAs on mortality. Most RCTs have primarily been performed to determine skeletal outcomes, whereas non-skeletal effects have been assessed as secondary outcomes. Only one-third of the RCTs had low level of 25OHD as a criterion for inclusion and a mean baseline 25OHD level below 50 nmol/L was only present in less than half of the analyses.

CONCLUSIONS

Published RCTs have mostly been performed in populations without low 25OHD levels. The fact that most MAs on results from RCTs did not show a beneficial effect does not disprove the hypothesis suggested by observational findings on adverse health outcomes of low 25OHD levels.