scholarly journals Rocking the boat of vitamin D research in schizophrenia and depression

2019 ◽  
Vol 25 (4) ◽  
pp. 249-250
Author(s):  
Henning Tiemeier
Keyword(s):  
Vitamin D ◽  
Observational Studies ◽  
Vitamin D Supplementation ◽  
Lifestyle Advice ◽  
Insufficient Evidence ◽  
Reverse Causality ◽  
Community Trials ◽  
Causality Hypothesis

SUMMARYA review of studies on vitamin D in schizophrenia and depression found insufficient evidence to inform advice for clinicians. On the basis of the review, I suggest advice for researchers, including better controlling for confounders in observational studies, testing the reverse causality hypothesis, studying vitamin D as a treatment or prevention specifically in patients with more pigmented skin, and prospective community trials of vitamin D supplementation combined with lifestyle advice.DECLARATION OF INTERESTNone.

Serum Vitamin D Level and Carotid Intima-Media Thickness: A Systematic Review and Meta-Analysis of Observational Studies and Randomized Control Trials

2020 ◽  
Vol 52 (05) ◽  
pp. 305-315
Author(s):  
Nasim Säidifard ◽  
Hadith Tangestani ◽  
Kurosh Djafarian ◽  
Sakineh Shab-Bidar
Keyword(s):  
Vitamin D ◽  
Observational Studies ◽  
Meta Analysis ◽  
Serum Vitamin ◽  
Intima Media Thickness ◽  
Carotid Intima Media Thickness ◽  
Vitamin D Supplementation ◽  
Inverse Association ◽  
Serum Vitamin D ◽  
Media Thickness

AbstractIt is reported that vitamin D deficiency is associated with carotid intima-media thickness (CIMT). In addition, several randomized clinical trials (RCTs) have studied the influence of vitamin D supplement on CIMT. However, results are inconclusive. This review aimed to systematically explore the potential link of the serum vitamin D level with CIMT pooling together observational studies and RCTs. PubMed and Scopus were searched for studies published until February 13, 2018. The Fisher’s z (SE) correlation coefficient, odds ratio (OR), and mean (SD) of changes in CIMT from baseline were used to perform meta-analysis in observational studies and RCTs, respectively. To pool data, both a fixed-effects model and a random-effects model (in case of heterogeneity) were used. Heterogeneity was assessed using Cochran’s Q and I2 tests. Nineteen observational studies and 3 RCTs met inclusion criteria. The pooled correlation coefficients of 17 observational studies showed [(Fisher’s z=− 0.41, 95% CI: –0.63 to –0.19, p<0.001), I2=96.9%, p < 0.001] a significant inverse association between serum vitamin D and risk of CIMT. Pooling three risk estimates of three studies [(OR = 1.69, 95% CI: 0.74 to 3.86, p=0.209); I2=085.1%, p<0.001)] indicated no significant association between serum vitamin D status and risk of CIMT. Combining data of RCTs showed vitamin D supplementation significantly reduced CIMT [(MD: –0.034, 95% CI: –0.62 to –0.05, p=0.012), I2=16.6%, p = 0.301]. Our findings show that serum vitamin D is inversely associated with CIMT and vitamin D supplementation may reduce CMIT.

scholarly journals The Role of Vitamin D in the Development of Diabetes Post Gestational Diabetes Mellitus: A Systematic Literature Review

Nutrients ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1733
Author(s):  
Amélie Keller ◽  
Carmen Varela Vazquez ◽  
Rojina Dangol ◽  
Peter Damm ◽  
Berit Lilienthal Heitmann ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Vitamin D ◽  
Literature Review ◽  
Gestational Diabetes ◽  
Gestational Diabetes Mellitus ◽  
Systematic Literature Review ◽  
Observational Studies ◽  
Vitamin D Supplementation ◽  
Diabetes Development ◽  
High Degree

Women diagnosed with gestational diabetes mellitus (GDM) are more likely to later develop diabetes. Evidence from some previous reviews suggests that low vitamin D status during pregnancy increases the risk of developing GDM, but whether vitamin D during pregnancy also influences the risk of diabetes post GDM is less well studied. Thus, the aim of this systematic literature review was to summarize the current available literature on that topic. This review considered observational studies and randomized controlled trials (RCTs). Five databases were searched. The risk of bias of the included studies was assessed. A total of six studies were included: three observational studies and three RCTs. Findings were inconsistent across the six included studies. However, when considering RCTs only, the findings more strongly suggested that vitamin D supplementation during and after pregnancy did not have an influence on markers of diabetes development or diabetes development post GDM. This systematic review highlights inconsistent findings on the associations between vitamin D supplementation or concentration during and after pregnancy and markers of diabetes development or diabetes development post GDM; and although results from randomized interventional studies more strongly suggested no associations, the conclusion holds a high degree of uncertainty.

scholarly journals Vitamin D Insufficiency May Account for Almost Nine of Ten COVID-19 Deaths: Time to Act. Comment on: “Vitamin D Deficiency and Outcome of COVID-19 Patients”. Nutrients 2020, 12, 2757

Nutrients ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3642 ◽  
Author(s):  
Hermann Brenner ◽  
Ben Schöttker
Keyword(s):  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Observational Studies ◽  
Vitamin D Insufficiency ◽  
Vitamin D Supplementation

Evidence from observational studies is accumulating, suggesting that the majority of deaths due to SARS-CoV-2 infections are statistically attributable to vitamin D insufficiency and could potentially be prevented by vitamin D supplementation [...]

scholarly journals Vitamin D in the Prevention and Treatment of Osteoarthritis: From Clinical Interventions to Cellular Evidence

Nutrients ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 243 ◽  
Author(s):  
Clara Yongjoo Park
Keyword(s):  
Vitamin D ◽  
Observational Studies ◽  
Pilot Trial ◽  
Clinical Results ◽  
Vitamin D Supplementation ◽  
Vitamin D Status ◽  
Randomized Controlled ◽  
The Relationship

Older adults are recommended vitamin D to prevent fractures. Though this population is also at risk of osteoarthritis (OA), the effect of vitamin D on OA is unclear and may differ by disease state. The relationship between vitamin D and OA during OA initiation and progression were considered in this narrative review of in vivo and in vitro studies. Regarding OA initiation in humans, the small number of published observational studies suggest a lack of association between induction of OA and vitamin D status. Most randomized controlled trials were performed in White OA patients with relatively high vitamin D status (>50 nmol/L). These studies found no benefit of vitamin D supplementation on OA progression. However, subset analyses and one randomized controlled pilot trial indicated that vitamin D supplementation may alleviate joint pain in OA patients with low vitamin D status (<50 nmol/L). As the etiology of OA is recently being more fully uncovered, better animal and cell models are needed. According to currently available clinical results, evidence is lacking to set a vitamin D level to prevent OA, and increasing vitamin D status above 50 nmol/L does not seem to benefit OA patients.

scholarly journals Why do so many trials of vitamin D supplementation fail?

2020 ◽  
Vol 9 (9) ◽  
pp. R195-R206
Author(s):  
Barbara J Boucher
Keyword(s):  
Vitamin D ◽  
Health Risks ◽  
Observational Studies ◽  
Health Benefits ◽  
Vitamin D Supplementation ◽  
Cellular Level ◽  
Future Health ◽  
Folk Remedy ◽  
Randomised Controlled ◽  
Do So

Our knowledge of vitamin D has come a long way since the 100 years it took for doctors to accept, between 1860 and 1890, that both sunlight and cod liver oil (a well-known folk remedy) cured and prevented rickets. Vitamins D2/D3 were discovered exactly a hundred years ago, and over the last 50 years vitamin D has been found to have many effects on virtually all human tissues and not just on bone health, while mechanisms affecting the actions of vitamin D at the cellular level are increasingly understood, but deficiency persists globally. Observational studies in humans have shown that better provision of vitamin D is strongly associated, dose-wise, with reductions in current and future health risks in line with the known actions of vitamin D. Randomised controlled trials, commonly accepted as providing a ‘gold standard’ for assessing the efficacy of new forms of treatment, have frequently failed to provide supportive evidence for the expected health benefits of supplementation. Such RCTs, however, have used designs evolved for testing drugs while vitamin D is a nutrient; the appreciation of this difference is critical to identifying health benefits from existing RCT data and for improving future RCT design. This report aims, therefore, to provide a brief overview of the evidence for a range of non-bony health benefits of vitamin D repletion; to discuss specific aspects of vitamin D biology that can confound RCT design and how to allow for them.

scholarly journals 1378The effect of vitamin D supplementation on acute respiratory infection -analysis of the D-Health Trial

2021 ◽  
Vol 50 (Supplement_1) ◽  
Author(s):  
Hai Pham ◽  
Mary Waterhouse ◽  
Catherine Baxter ◽  
Briony Romero ◽  
Donald McLeod ◽  
...  
Keyword(s):  
Vitamin D ◽  
Observational Studies ◽  
Regression Models ◽  
Average Duration ◽  
Acute Respiratory Tract Infection ◽  
Vitamin D Supplementation ◽  
Duration Of Symptoms ◽  
Potential Impact ◽  
Rate Ratios ◽  
Randomised Controlled

Abstract Background Observational studies link vitamin D deficiency with acute respiratory tract infection (ARTI) but results from randomised controlled trials are heterogeneous. Methods We used data from The D-Health Trial (N = 21,315); ARTI was a pre-specified trial outcome. Participants were men and women aged 60 to 79 years (with volunteers aged up to 84 years), supplemented with monthly doses of 60,000 international units of vitamin D and followed for up to 5 years. Participants were asked to report occurrence of ARTI over the previous month via annual surveys, and a subset of participants completed 8-week respiratory symptom diaries in winter. We used regression models to estimate odds ratios, rate ratios and rate differences. Results Vitamin D supplementation did not reduce the risk of ARTI (survey OR 0.98, 95% CI 0.93 to 1.02; diary OR 0.98, 95% CI 0.83 to 1.15). Analyses of diary data showed that vitamin D reduced the average duration by 0.5 days (95% CI 0.2 to 0.7 days) and the average number of days with severe symptoms by 0.4 days (95% CI 0.3 to 0.6 days). Conclusions Monthly bolus doses of 60,000 IU of vitamin D did not reduce the overall risk of ARTI but slightly reduce the duration of symptoms in the general population. Key messages The reduction in the duration of symptoms suggests a potential impact of vitamin D on the immune response to infection.

scholarly journals Controlled trials of vitamin D, causality and type 2 statistical error

2014 ◽  
Vol 19 (3) ◽  
pp. 409-414 ◽  
Author(s):  
OIiver Gillie
Keyword(s):  
Vitamin D ◽  
Early Life ◽  
Observational Studies ◽  
Scientific Evidence ◽  
Statistical Error ◽  
Reverse Causality ◽  
Reverse Causation ◽  
Null Result ◽  
Low Levels

AbstractTwo recent studies published in The Lancet (Autier et al. (2013) Lancet Diabetes Endocrinol2, 76–89 and Bolland et al. (2014) Lancet Diabetes Endocrinol2, 307–320) have concluded that low levels of vitamin D are not a cause but a consequence of ill health brought about by reduced exposure to the sun, an association known as ‘reverse causality’. The scientific evidence and reasoning for these conclusions are examined here and found to be faulty. A null result in a clinical trial of vitamin D in adults need not lead to a conclusion of reverse causation when low vitamin D is found in observational studies of the same disease earlier in life. To assume an explanation of reverse causality has close similarities with type 2 statistical error.For example, a null result in providing vitamin D for treatment of adult bones that are deformed in the pattern of the rachitic rosary would not alter the observation that lack of vitamin D can cause rickets in childhood and may have lasting consequences if not cured with vitamin D. Other examples of diseases considered on a lifetime basis from conception to adulthood are used to further illustrate the issue, which is evidently not obvious and is far from trivial.It is concluded that deficiency of vitamin D in cohort studies, especially at critical times such as pregnancy and early life, can be the cause of a number of important diseases. Denial of the possible benefits of vitamin D, as suggested by insistent interpretation of studies with reverse causation, may lead to serious harms, some of which are listed.

Vitamin D in older people

2014 ◽  
Vol 24 (2) ◽  
pp. 158-171 ◽  
Author(s):  
Miles D Witham ◽  
Gavin Francis
Keyword(s):  
Vitamin D ◽  
Older People ◽  
Biological Effects ◽  
Association Studies ◽  
Vitamin D Supplementation ◽  
Falls Prevention ◽  
Reverse Causality ◽  
Hydroxyvitamin D ◽  
Beneficial Effects ◽  
Wide Range

SummaryVitamin D has a wide range of biological effects beyond calcium and bone metabolism, and low 25-hydroxyvitamin D levels have been associated with many disease states in recent years, including cardiovascular disease, diabetes, infections and cancer. Association studies of vitamin D are notoriously prone to confounding and to reverse causality, however, and current intervention trial data for non-skeletal indications have been disappointing. Vitamin D is indicated for treatment of osteomalacia in older people, falls prevention in institutionalized older people, and as adjunctive therapy for osteoporosis. Large trials currently underway will ascertain whether potentially beneficial effects of vitamin D supplementation on all-cause mortality in older people are borne out.

scholarly journals Relation between the vitamin D status and the occurrence and severity of thyroid malignancy

2021 ◽  
Vol 17 (7) ◽  
pp. 557-561
Author(s):  
L.A. Nikitiuk ◽  
Korsak Yu.
Keyword(s):  
Vitamin D ◽  
Thyroid Cancer ◽  
Vitamin D Deficiency ◽  
Large Volume ◽  
Observational Studies ◽  
Medical Literature ◽  
Vitamin D Supplementation ◽  
Vitamin D Status ◽  
Vdr Gene ◽  
Cancer Data

Background. In spite of large volume of data linking vitamin D with cardiovascular morbidity, autoimmunity, cancer, and virtually every organ system, vitamin D and thyroid is a lesser-known aspect of vitamin D in clinical practice. The association between vitamin D deficiency and thyroid cancer is controversial. Some studies have demonstrated that higher serum vitamin D levels might protect against thyroid cancer, whereas others have not, or have even indicated the opposite to to be the case. This review intends to highlight the current literature on the impact of vitamin D status on thyroid cancer. Materials and methods. References for this review were identified through searches of PubMed for articles published to from 2005 to June 2021 using the terms “thyroid cancer” and “vitamin D”. Results. A large volume of medical literature is available from observational studies linking vitamin D with thyroid cancer. Data from interventional studies documenting beneficial effects of vitamin D on thyroid autoimmunity is also available, but lesser than that from observational studies. Short-term high dose oral vitamin D supplementation reduces TPOAb titers. Certain vitamin D receptor (VDR) gene polymorphism have been linked to increased occurrence of autoimmune thyroid disorders. Vitamin D deficiency, decreased circulating calcitriol has been linked to increased thyroid cancer. Certain VDR gene polymorphisms have been linked with increased as well as decreased occurrence of thyroid cancer. Data is scant on use of vitamin D and its analogues for treating thyroid cancer. The results suggest that Vitamin D deficiency may have value as a negative prognostic indicator in papillary thyroid cancer and that pre-operative laboratory evaluation may be less useful. This is important because Vitamin D deficiency is modifiable. Conclusions. In spite of large volume of medical literature from observational studies linking vitamin D with thyroid cancer, meaningful concrete clinical data on impact of vitamin D supplementation on hard clinical end points in these disorders is lacking, and should be the primary area of research in the next decade.

scholarly journals Effect of Vitamin D Supplementation on Risk of Breast Cancer: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

2021 ◽  
Vol 8 ◽  
Author(s):  
Ziyi Li ◽  
Liangzhi Wu ◽  
Junguo Zhang ◽  
Xin Huang ◽  
Lehana Thabane ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Systematic Review ◽  
Vitamin D ◽  
Confidence Interval ◽  
Protective Effect ◽  
Observational Studies ◽  
Meta Analysis ◽  
Vitamin D Supplementation ◽  
Controlled Trials ◽  
Randomized Controlled

Objective: Laboratory findings indicated that vitamin D might have a potent protective effect on breast cancer, but epidemiology studies reported conflicting results. The aim of the study was to conduct a systematic review and meta-analysis to clarify the efficacy of vitamin D supplementation on risk of breast cancer.Methods: MEDLINE, EMBASE, The Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and abstracts of three major conferences were searched (up to December 8, 2020). Parallel randomized controlled trials (RCTs) examining the efficacy of vitamin D supplementation on risk of breast cancer or change of mammography compared with placebo in females were included. Data were meta-analyzed using a random-effects model. Bayesian meta-analysis was conducted to synthesize the results using data from observational studies as priors.Results: Seven RCTs were identified for effect of vitamin D on risk of breast cancer, with 19,137 females included for meta-analysis. No statistically significant effect of vitamin D on risk of breast cancer was found in classical random-effects meta-analysis (risk ratio = 1.04, 95% confidence interval: 0.84–1.28, p = 0.71). When Bayesian meta-analyses were conducted, results remained non-significant. There was no statistically significant effect of vitamin D on mammography density observed: mean difference = 0.46, 95% confidence interval: −2.06 to 2.98, p = 0.72.Conclusion: There is insufficient evidence to support the efficacy of vitamin D supplementation in breast cancer risk and change of mammography density. The protective effect of vitamin D on risk of breast cancer from previous observational studies may be overestimated.Systematic Review Registration: PROSPERO, identifier CRD42019138718.

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