Associations Between Vitamin D Levels and Risk of Heart Failure: A Bidirectional Mendelian Randomization Study

Cardiovascular disease outcomes in relation to 25-hydroxyvitamin D and its seasonal variation: Results from the BiomarCaRE consortium

BACKGROUND

It has been hypothesized but seldom tested that the winter excess in cardiovascular disease (CVD) is related to hypovitaminosis D. The present study examined the association between CVD and (i) seasonality of 25-hydroxyvitamin D (25[OH]D) and (ii) individual 25(OH)D concentrations.

METHODS AND FINDINGS

Harmonized 25(OH)D data were obtained from the Biomarkers for Cardiovascular Risk Assessment in Europe (BiomarCaRE) project, including 79,570 participants examined between 1984 and 2010. One 25(OH)D measurement was available per participant. Primary endpoints were CVD incidence (coronary heart disease or stroke; n = 6006) and CVD mortality (n = 2985). To study (i), Poisson regression-derived rate ratios were compared according to two-month categories, ordered by baseline 25(OH)D concentrations. To study (ii), Cox regression-derived hazard ratios were compared according to quarters of baseline 25(OH)D concentrations. With respect to (i), despite a median 25(OH)D concentration ratio of 1:1.79, the trough months of 25(OH)D in March and April had a similar CVD incidence as the peak months of 25(OH)D in August and September (rate ratio: 1.07, 95% CI: 0.98-1.17). CVD mortality was slightly higher in the trough months compared to the peak months (rate ratio: 1.27, 95% CI: 1.12-1.44) but not compared to the other months (despite median 25[OH]D concentration ratios up to 1:1.62; p ≥ 0.077). The CVD mortality peak in January preceded the 25(OH)D trough, not adhering to the temporality criterion of Bradford Hill. With respect to (ii), compared to the lowest quarter, the highest quarter of 25(OH)D was associated with lower CVD incidence (hazard ratio: 0.82, 95% CI: 0.76-0.89) and CVD mortality (hazard ratio: 0.64, 95% CI: 0.57-0.72).

CONCLUSION

The present study does not support the hypothesis that seasonal increases in CVD are driven by short-term reductions in 25(OH)D. As in most observational studies, higher 25(OH)D concentrations were inversely associated with CVD.

Application of Mendelian randomized analysis method in Vitamin D research: A 10-year bibliometric analysis

Vitamin D is an open-cyclic steroidal trace organic compound that plays a crucial role in human metabolism and nutritional health. In recent years, Mendelian randomization (MR) has emerged as a widely adopted method for analyzing causal relationships, particularly in studying the association between Vitamin D and related diseases. However, no bibliometric analyses have been conducted to explore the research hotspots and trends regarding Vitamin D status in MR studies. This study utilized the Web of Science Core Collection as a source database and retrieved articles on Vitamin D status in MR published from 2014 to 2024. Bibliometric and visualization analyses utilized VOSviewer, Microsoft Excel 2021, and Scimago Graphica. An in-depth analysis of country or region, authors, journals, keywords, and references were performed to provide insights into the content related to the field. A total of 186 documents authored by 1122 contributors across 30 countries were identified. China and the University of Bristol had the highest publication counts, with 94 and 19 articles, respectively. The nutrients published the largest number of articles, and J Brent Richards was the largest contributors. The most frequently used keywords included "Mendelian randomization," "Vitamin D," "25-hydroxyVitamin D," "obesity," and "Type 2 Diabetes." The current research focuses on using MR methods to explore the associations between Vitamin D status and metabolic, cardiovascular, immune skin, psychiatric and neurological diseases. The related research in this field will continue to increase in the next few years, which is a promising research prospect in this field. This study systematically reviews the literature from the past decade, revealing research hotspots and trends in the field of Vitamin D status within MR studies. This information will provide a strong reference for readers and researchers.

Vitamin D and human health: evidence from Mendelian randomization studies

We summarized the current evidence on vitamin D and major health outcomes from Mendelian randomization (MR) studies. PubMed and Embase were searched for original MR studies on vitamin D in relation to any health outcome from inception to September 1, 2022. Nonlinear MR findings were excluded due to concerns about the validity of the statistical methods used. A meta-analysis was preformed to synthesize study-specific estimates after excluding overlapping samples, where applicable. The methodological quality of the included studies was evaluated according to the STROBE-MR checklist. A total of 133 MR publications were eligible for inclusion in the analyses. The causal association between vitamin D status and 275 individual outcomes was examined. Linear MR analyses showed genetically high 25-hydroxyvitamin D (25(OH)D) concentrations were associated with reduced risk of multiple sclerosis incidence and relapse, non-infectious uveitis and scleritis, psoriasis, femur fracture, leg fracture, amyotrophic lateral sclerosis, anorexia nervosa, delirium, heart failure, ovarian cancer, non-alcoholic fatty liver disease, dyslipidemia, and bacterial pneumonia, but increased risk of Behçet's disease, Graves' disease, kidney stone disease, fracture of radium/ulna, basal cell carcinoma, and overall cataracts. Stratified analyses showed that the inverse association between genetically predisposed 25(OH)D concentrations and multiple sclerosis risk was significant and consistent regardless of the genetic instruments GIs selected. However, the associations with most of the other outcomes were only pronounced when using genetic variants not limited to those in the vitamin D pathway as GIs. The methodological quality of the included MR studies was substantially heterogeneous. Current evidence from linear MR studies strongly supports a causal role of vitamin D in the development of multiple sclerosis. Suggestive support for a number of other health conditions could help prioritize conditions where vitamin D may be beneficial or harmful.

Vitamin D Deficiency in Patients Hospitalized for Heart Failure Living in the Tropics

Background and Objectives

Vitamin D, as a steroid hormone, has multiple effects on human body and its deficiency has been associated with an increased risk of heart failure (HF) and unfavorable outcomes. The present study investigated the prevalence of vitamin D deficiency (VDD) and its relationship with cardiometabolic parameters in patients hospitalized for HF living in the city of Recife (latitude 8° South).

Methods

Analytical cross-sectional study, with men and women aged 40-64 years. The HF group was recruited during hospitalization due to decompensation. A matched control group was recruited from the general endocrine clinics. Vitamin D status was assessed by measuring serum 25-hydroxyvitamin D (25OHD), considering deficiency when 25OHD <20 ng/mL (<50 nmol/L).

Results

A total of 243 patients were evaluated (HF group: 161, control group: 82). Lower serum 25OHD levels were observed in the HF group (25.2±9.4 vs. 30.0±7.7ng/mL; p<0.001), as well as a higher prevalence of VDD (27.3% vs. 9.8%; prevalence ratio, 2.80; 95% confidence interval, 1.38-5.67; p=0.002). In patients with HF, VDD was associated with diabetes mellitus (65.9% vs. 41.0%; p=0.005) and female sex (65.9% vs. 44.4%; p=0.015). In the subgroup with VDD, higher values of hemoglobin A1c (7.9% [6.0-8.9] vs. 6.2% [5.7-7.9]; p=0.006) and dyslipidemia were also observed.

Conclusions

We found higher rates of VDD in patients hospitalized for HF and this was associated with deleterious laboratory metabolic parameters.

Health Effects of Vitamin D Supplementation: Lessons Learned From Randomized Controlled Trials and Mendelian Randomization Studies

Vitamin D plays an important role in calcium homeostasis and many cellular processes. Although vitamin D supplements are widely recommended for community-dwelling adults, definitive data on whether these supplements benefit clinically important skeletal and extraskeletal outcomes have been conflicting. Although observational studies on effects of vitamin D on musculoskeletal and extraskeletal outcomes may be confounded by reverse causation, randomized controlled studies (RCTs) and Mendelian randomization (MR) studies can help to elucidate causation. In this review, we summarize the recent findings from large RCTs and/or MR studies of vitamin D on bone health and risk of fractures, falls, cancer, and cardiovascular disease, disorders of the immune system, multiple sclerosis, and mortality in community-dwelling adults. The primary analyses indicate that vitamin D supplementation does not decrease bone loss, fractures, falls, cancer incidence, hypertension, or cardiovascular risk in generally healthy populations. Large RCTs and meta-analyses suggest an effect of supplemental vitamin D on cancer mortality. The existence of extraskeletal benefits of vitamin D supplementations are best documented for the immune system especially in people with poor vitamin D status, autoimmune diseases, and multiple sclerosis. Accumulating evidence indicates that vitamin D may reduce all-cause mortality. These findings, in mostly vitamin D-replete populations, do not apply to older adults in residential communities or adults with vitamin D deficiency or osteoporosis. The focus of vitamin D supplementation should shift from widespread use in generally healthy populations to targeted vitamin D supplementation in select individuals, good nutritional approaches, and elimination of vitamin D deficiency globally. © 2023 American Society for Bone and Mineral Research (ASBMR).

Recent Advances in Association Between Vitamin D Levels and Cardiovascular Disorders

PURPOSE OF REVIEW

In this review, we discuss the evidence that vitamin D affects cardiovascular disease through interventional and observational studies and their corresponding association mechanisms. We also highlight the need for further research to definitively conclude clinical recommendations based on preliminary data and determine the extent to which vitamin D levels may impact the incidence and prognosis of major cardiovascular diseases in the future.

RECENT FINDINGS

Cardiovascular disease has long been recognized as the leading cause of morbidity and mortality worldwide, with many risk factors implicated in its pathogenesis. Vitamin D is a risk factor that, despite being known to be crucial for its role in maintaining bone health, also has several extra-skeletal effects due to vitamin D receptors in vascular smooth muscle and cardiomyocytes. Recent studies have documented a significant association between higher vitamin D levels and lower risk of each cardiovascular disease entity; 11 studies between serum vitamin D and heart failure, 7 studies between serum vitamin D and hypertension, 8 studies between serum vitamin D and coronary artery disease, and 5 studies between serum vitamin D and atrial fibrillation. More studies documenting a significant association between increased serum vitamin D and cardiovascular disease are in the context of heart failure compared to hypertension, coronary artery disease, and atrial fibrillation. Conversely, a significant association between increased serum vitamin D and a lower risk of atrial fibrillation is reported in fewer studies compared to the association of vitamin D with other cardiovascular disease entities. Although there is evidence documenting a clear significant association of vitamin D under each category, further research is still needed to definitively conclude the role of vitamin D in cardiovascular disease management.

Calcipotriol Attenuates Form Deprivation Myopia Through a Signaling Pathway Parallel to TGF-β2-Induced Increases in Collagen Expression

Purpose

To determine the role of calcipotriol, a vitamin D3 analogue, in myopia development and altering the expression of scleral α1 chain of type I collagen (Col1α1) in mice. We also aimed to identify if the signaling pathway mediating the above changes is different from the one involved in transforming growth factor β2 (TGF-β2)-mediated increases of COL1A1 in cultured human scleral fibroblasts (HSFs).

Methods

C57BL/6J mice were either intraperitoneally injected with calcipotriol and subjected to form deprivation (FD) or exposed to normal refractive development for 4 weeks. Scleral vitamin D receptor (Vdr) expression was knocked down using a Sub-Tenon's capsule injection of an adeno-associated virus-packaged short hairpin RNA (AAV8-shRNA). Refraction and biometric measurements evaluated myopia development. A combination of knockdown and induction strategies determined the relative contributions of the vitamin D3 and the TGF-β2 signaling pathways in modulating COL1A1 expression in HSFs.

Results

Calcipotriol injections suppressed FD-induced myopia (FDM), but it had no significant effect on normal refractive development. AAV8-shRNA injection reduced Vdr mRNA expression by 42% and shifted the refraction toward myopia (-3.15 ± 0.99D, means ± SEM) in normal eyes. In HSFs, VDR knockdown reduced calcipotriol-induced rises in COL1A1 expression, but it did not alter TGF-β2-induced increases in COL1A1 expression. Additionally, TGF-β2 augmented calcipotriol-induced rises in COL1A1 expression. TGF-β receptor (TGFBRI/II) knockdown blunted TGF-β2-induced increases in COL1A1 expression, whereas calcipotriol-induced increases in VDR and COL1A1 expression levels were unaltered.

Conclusions

Scleral vitamin D3 inhibits myopia development in mice, potentially by activating a VDR-dependent signaling pathway and increasing scleral COL1A1 expression levels.