Vitamin D intake and risk of CVD and all-cause mortality: evidence from the Caerphilly Prospective Cohort Study

Effects of vitamin D supplementation on metabolic syndrome parameters in patients with obesity or diabetes in Brazil, Europe, and the United States: A systematic review and meta-analysis

Plasma 25-dihydroxyvitamin D levels appear reduced in patients with obesity or type 2 diabetes, as reported in several observational studies. However, the association between these reduced hormone levels and metabolic parameters is unclear. In any case, vitamin D supplementation in patients with Metabolic Syndrome is standard. Still, the impacts of this supplementation on conditions such as glycemia, blood pressure, and lipidemia are debatable. Based on this question, we carried out a systematic review and meta-analysis of randomized clinical trials in Brazil, Europe, and the United States that analyzed the effects of vitamin D supplementation on Metabolic Syndrome parameters in patients with obesity or type 2 diabetes. Our search yielded 519 articles and included 12 randomized controlled trials in the meta-analysis. Vitamin D supplementation had no effect on any of the outcomes analyzed (fasting blood glucose and insulinemia, glycated hemoglobin, HOMA index, systolic and diastolic blood pressure, weight, waist circumference, total cholesterol, LDL and HDL, and triglycerides). However, subgroup analyses indicated that using vitamin D up to 2000 IU daily reduced participants' fasting blood glucose and glycated hemoglobin. Furthermore, the intervention reduced diastolic blood pressure only in participants with vitamin D deficiency. At least two studies showed a high risk of bias using the Rob2 protocol. According to the GRADE protocol, the evidence quality varied from moderate to very low. These results indicate that vitamin D supplementation does not improve patients' metabolic parameters and that the association between plasma 25-dihydroxyvitamin D levels and Metabolic Syndrome may not be causal but caused by other confounding characteristics. However, in any case, the quality of evidence is still low, and more randomized clinical trials are essential to clarify these relationships.

From A to E: Uniting vitamins against stroke risk-A systematic review and network meta-analysis

BACKGROUND AND AIM

Stroke represents a significant public health challenge, necessitating the exploration of preventive measures. This network meta-analysis aimed to assess the efficacy of different vitamin treatments compared to a placebo in preventing stroke.

METHODS

A systematic electronic search in databases including PubMed, EmBASE, Web of Science, clinicaltrials.gov, and Google Scholar until 31 May 2023 was conducted, to identify published studies investigating the association between vitamin intake and the risk of stroke. Pooled risk ratio (RR) with 95% confidence intervals (CIs) was calculated using a frequentist network meta-analysis. Furthermore, we ranked vitamins based on p-scores, facilitating a comparative assessment of their effectiveness in preventing stroke.

RESULTS

A total of 56 studies, including 17 randomized controlled trials (RCTs) and 39 cohort studies were analyzed. Direct estimates obtained from network meta-analysis, we found that vitamin A (RR: .81 [.72-.91]), vitamin B-complex (RR: .85 [.74-.97]), vitamin B6 (RR: 79 [.68-.92]), folate (RR: .86 [.75-.97]), vitamin C (RR: .77 [.70-.85]) and vitamin D (RR: .73 [.64-.83]) were significantly associated with a decreased stroke risk. However, no significant association was observed for vitamin B2, vitamin B12, and vitamin E. Subsequent to network meta-analysis, vitamins were ranked in decreasing order of their efficacy in stroke prevention based on p-score, with vitamin D (p-score = .91), vitamin C (p-score = .79), vitamin B6 (p-score = .70), vitamin A (p-score = .65), vitamin B-complex (p-score = .53), folate (p-score = .49), vitamin B2 (p-score = .39), vitamin E (p-score = .28), vitamin B12 (.13) and placebo (.10).

CONCLUSION

Our study has established noteworthy connections between vitamin A, vitamin B-complex, vitamin B6, folate, vitamin C, and vitamin D in the realm of stroke prevention. These findings add substantial weight to the accumulating evidence supporting the potential advantages of vitamin interventions in mitigating the risk of stroke. However, to solidify and validate these observations, additional research is imperative. Well-designed clinical trials or cohort studies are needed to further explore these associations and formulate clear guidelines for incorporating vitamin supplementation into effective stroke prevention strategies.

Oral health and 10-year cardiovascular risk in US adults: mediating role of inflammatory diet and vitamin D

OBJECTIVE

To investigate whether E-DII or vitamin D mediates the relationship between oral health and cardiovascular disease (CVD) risk.

METHODS

This study involved 6616 participants aged over 30 years old from the National Health and Nutrition Examination Survey (NHANES) in 2009-2014. Dietary inflammation and 10-year CVD risk were evaluated via the Energy-adjusted Dietary Inflammatory Index (E-DII) and the Framingham Risk Score (FRS), respectively. We used correlation analysis and mediation analysis to investigate the role of dietary inflammation and vitamin D in the relationship between oral health and CVD risk.

RESULTS

Oral health indicators and CVD risk were positively correlated with E-DII (r > 0, P < 0.001) and negatively correlated with vitamin D levels (r < 0, P < 0.001). The estimated mediating role of E-DII and vitamin D in the overall association between oral health and 10-year risk of CVD ranged from 4.9 to 7.5% and 6.6 to 11.6%, respectively. Furthermore, the mediation proportion of E-DII and vitamin D levels in the total association between oral health indicators and FRS were increased in participants without periodontitis.

CONCLUSION

Both E-DII and serum vitamin D were mediated the association between oral problems and 10-year CVD risk, especially in participants without periodontitis. Among them, E-DII played a positive mediating role, and serum vitamin D levels was a negative mediator.

CLINICAL RELEVANCE

Anti-inflammatory diet and prevention of vitamin D deficiency might reduce the impact of oral problems on cardiovascular disease risk to some extent. The study highlights the important role of oral health and dietary inflammation and vitamin D in primary prevention of cardiovascular disease.

Vitamin D intake and all-cause and cause-specific mortality in Japanese men and women: the Japan Public Health Center-based prospective study

While higher circulating 25-hydroxyvitamin D concentrations have been reported to be associated with decreased risk of all-cause mortality, evidence on dietary vitamin D intake is limited and inconsistent. We investigated whether vitamin D intake is associated with all-cause and cause-specific mortality among Japanese adults. Participants were 42,992 men and 50,693 women who responded to the second survey of the Japan Public Health Center-based Prospective Study (1995-1998) and who were followed up for mortality through 2018. Dietary intake was ascertained using a validated food frequency questionnaire. Hazard ratios of deaths from the second survey to December 2018 were estimated using Cox proportional hazard regression analysis. During follow-up, we identified 22,630 deaths. Overall, the third and fourth quintiles, but not the highest quintile, of vitamin D intake were each associated with a significantly lower risk of all-cause mortality. In subgroups characterized by low sunlight exposure, risk of all-cause mortality decreased linearly with increasing vitamin D intake. The multivariable-adjusted hazard ratios (95% confidence intervals) of all-cause mortality for the highest versus lowest quintile of vitamin D intake were 0.87 (0.79-0.95) in women and 0.88 (0.79-0.97) in residents of higher latitude areas. Lower risk was also observed for all-cause mortality in participants with hypertension and for heart disease mortality in those with higher calcium intake. Higher vitamin D intake was associated with decreased risk of ischemic stroke and pneumonia mortality. Higher dietary vitamin D was associated with a lower risk of mortality among individuals with low sunlight exposure or hypertension. Individuals with potentially low vitamin D may benefit from increasing dietary vitamin D intake for the prevention of premature death.

Serum 25-hydroxyvitamin D is associated with stroke history in a reverse J-shape

Background

25-hydroxyvitamin D [25(OH)D], the major form of vitamin D in the body, has a non-linear association with stroke risk. However, the association is not fully understood. The specific shape of the association and the ideal value of 25(OH)D related to minimum risk of stroke remain unclear.

Aim

We conducted the study to establish the correlation between circulating 25(OH)D and stroke history and determine the ideal value of 25(OH)D in relation to the lowest stroke prevalence.

Methods

Data from the National Health and Nutrition Examination Survey (NHANES) were used for analyzes. We used multivariate logistic regression analysis with fitted smooth curves to explore the relationship between 25(OH)D and self-reported stroke history. Subsequently, 40,632 participants were enrolled in the study.

Results

A reverse J-shaped association between 25(OH)D and stroke history was determined, where the lowest stroke prevalence for the 25(OH)D level was about 60 nmol/L. After adjusting for confounding factors, prevalence of stroke showed an increasing trend below and above the middle quintile (53.2-65.4 nmol/L) of 25(OH)D. Participants with 25(OH)D levels in the lowest quintile (≤ 39.3 nmol/L) had a 38% increased prevalence of stroke (OR 1.38, 95 %CI 1.12-1.70), while those in the higher level range of 25(OH)D (65.5-80.8 nmol/L) had a 27% higher stroke prevalence (OR 1.27, 95 %CI 1.03-1.57).

Conclusion

Using data from a large, cross-sectional cohort program, we found that circulating 25(OH)D was related to stroke history in a reverse J-shaped manner. Given how the causal relationship between circulating 25(OH)D and history of stroke has not been established, more high-quality evidence based on the reverse J-shaped feature is needed to elucidate the link between vitamin D and stroke risk, and the effect of vitamin D supplements on stroke prevention.

A Study of Vitamin D and Its Correlation With Severity and Complication of Congestive Heart Failure: A Systematic Review

Many studies have shown that vitamin D is a crucial modulator of hypertension and cardiovascular illness, including heart failure. Heart failure (HF) is still the leading cause of mortality worldwide. Patients with heart failure who have low vitamin D levels experience worse outcomes, which associate with known clinical correlations and biomarkers. Additionally, patients with low vitamin D levels are more likely to have diabetes, hypertension, atherosclerosis, and other precursor conditions to heart failure. There are some hints in recent experimental research on how vitamin D can have cardioprotective effects. Vitamin D supplementation might improve ventricular remodeling in heart failure patients, however, this is still unclear. It aims to evaluate the association between vitamin D and congestive heart failure (CHF). This systematic review used research from the previous ten years (January 2012-2022) retrieved from the following databases: PubMed/PMC (PubMed Central)/Medline and Cochrane Library. Using the Preferred Reporting Item for Systematic Review and Meta-analysis (PRISMA) 2020 guidelines, removing duplicates, screening of title and abstract, application of eligibility criteria, and quality appraisal, 13 articles were retained for systemic review. There were 10 randomized controlled trials and three observational studies. Vitamin D supplementation lowers serum inflammatory marker levels and improves the quality of life in CHF patients. Vitamin D treatment inhibits ventricular remodeling and improves cardiac function in a patient with CHF.

Therapeutic Effects of Traditional Chinese Medicine for Patients With Coronary Heart Disease After Treatment of Revascularization: A Prospective Cohort Study in the Northern of China

Aim: To investigate the compliance and the outcome of Traditional Chinese Medicine (TCM) in patients with coronary heart disease (CHD) after treatment of revascularization.

Methods: In this prospective cohort study, the non-exposure group (NEG), low-exposure group (LEG), and high-exposure group (HEG) were divided after 2 years follow-up. The primary outcome was a composite of death from cardiovascular causes, non-lethal myocardial infarction, heart transplantation, or stroke. Time-to-event data were evaluated by using the Cox regression analysis with hazard ratios (HRs) and 95% CIs. Then, the two-sided p-values were calculated by using the Cox models. In order to indicate the therapeutic effects of TCM on the CHD after revascularization, the survival analysis and the nested case–control study were conducted separately.

Results: There were 1,003 patients with CHD enrolled, 356 patients (35.49%) did not choose the TCM, 379 patients (37.79%) used the TCM seldom, and only 268 patients (26.72%) used TCM regularly. A total of 653 patients with revascularization participated in the prospective cohort study. Over the duration of the trial, the primary endpoints occurred in 12 (4.35%), 11 (4.80%), and 2 (1.35%) patients in the NEG, LEG, and HEG, while the secondary endpoints occurred in 84 (30.43%), 57 (24.89%), and 15 (10.14%) patients in the NEG, LEG, and HEG, respectively. The occurrence time of secondary endpoint events in HEG was significantly postponed (p < 0.001) compared with the other cohorts. The Cox regression analysis indicated that the HRs in the primary endpoints, the secondary endpoint events, the major adverse cardiac and cerebrovascular events (MACCE), and the composite endpoint events for HEG were all around 0.3 (p < 0.05) and HRs for LEG were all around 0.8. The results of the nested case–control study showed that the TCM exposure was significantly different between the cases and controls in the secondary endpoints (p < 0.05), while no significant difference in the primary endpoints (p > 0.05), but the percentage of HEG in the cases was extremely lower than the controls.

Conclusion: The HEG-TCM may improve the outcomes of the patients with CHD after treatment of revascularization.

Registration:http://www.chictr.org.cn. Unique identifier: ChiCTR-OOC-17012995.

Effects of 12 Months of Vitamin D Supplementation on Physical Fitness Levels in Postmenopausal Women with Type 2 Diabetes

INTRODUCTION

It is common for postmenopausal women to receive a vitamin D supplementation prescription to assist in preventing future falls and to maintain bone health. However, the association between vitamin D supplementation and physical fitness components has not been studied in older women with diabetes.

OBJECTIVE

We examined the influence of 12 months of vitamin D supplementation on the components of physical fitness in postmenopausal women with type 2 diabetes mellitus (T2DM).

METHODS

Thirty-five postmenopausal women (62.48 ± 7.67 years; 154.6 ± 5.11 cm; 73.93 ± 15.43 kg; 31.13 ± 5.82 BMI) with a diagnosis of T2DM participated in this longitudinal study where participants were supplemented with 1000 IU/day of vitamin D over 12 months. Subjects performed fasting blood samples, anthropometric assessments, body composition, clinical exams, and physical tests at 6-month intervals (P0, P6, and P12).

RESULTS AND CONCLUSION

Vitamin D supplementation alone was effective in postmenopausal women in increasing serum vitamin D levels, altering muscle strength levels, promoting improvements in muscle function, as well as preventing and controlling fragility caused by T2DM and aging.

Association between Vitamin D and Risk of Stroke: A PRISMA-Compliant Systematic Review and Meta-Analysis

BACKGROUND

Previous studies have shown inconsistent results for associations between vitamin D and risk of stroke. We gathered the existing published articles and conducted this meta-analysis with the aim to explore the association between vitamin D and risk of stroke.

METHODS

We searched for articles exploring the association between vitamin D and risk of stroke and published before April 2021 in the following databases: PubMed, Web of Science, MEDLINE, EMBASE, and Google Scholar. All statistical analyses were made using STATA 12.0 software. Q test and I2 were applied to examine heterogeneities between studies.

RESULTS

For the association between serum levels of 25(OH) vitamin D and risks of stroke, the present analysis included 20 cohort studies (including 213,276 participants) and a case-control analysis (including 13,642 participants). Additionally, the analysis included 15 studies (including 41,146 participants given vitamin D supplementation and 41,163 participants given placebo) to evaluate the influence of vitamin D supplementation on risk of stroke. Higher circulating levels of 25(OH) vitamin D were associated with a reduced risk of stroke (odds ratio/relative risk = 0.78, 95% confidence interval [CI]: 0.70-0.86, I2 = 41.5%, p = 0.025). However, the present analysis showed that vitamin D supplementation did not influence the risk of stroke (hazard ratio = 1.05, 95% CI: 0.96-1.14, I2 = 2.3%, p = 0.425).

CONCLUSIONS

Our analysis indicated that lower circulating level of vitamin D was associated with an elevated risk of stroke, but extra supplement of vitamin D failed to show benefit in decreasing the risk of stroke. Further research and study are also needed to show the role of vitamin D in relation to stroke.

Serum Vitamin D Affected Type 2 Diabetes though Altering Lipid Profile and Modified the Effects of Testosterone on Diabetes Status

Numerous studies have investigated the associations between serum vitamin D or testosterone and diabetes; however, inconsistencies are observed. Whether there is an interaction between vitamin D and testosterone and whether the lipid profile (total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C)) mediates the association between vitamin D and diabetes is unclear. To investigate the effect of vitamin D and testosterone on impaired fasting glucose (IFG) or type 2 diabetes mellitus (T2DM), 2659 participants from the Henan Rural Cohort were included in the case-control study. Generalized linear models were utilized to estimate associations of vitamin D with IFG or T2DM and interactive effects of vitamin D and testosterone on IFG or T2DM. Principal component analysis (PCA) and mediation analysis were used to estimate whether the lipid profile mediated the association of vitamin D with IFG or T2DM. Serum 25(OH)D₃, 25(OH)D₂, and total 25(OH)D levels were negatively correlated with IFG (odds ratios (ORs) (95% confidence intervals (CIs)): 0.99 (0.97, 1.00), 0.85 (0.82, 0.88), and 0.97 (0.96, 0.98), respectively). Similarity results for associations between serum 25(OH)D₂ and total 25(OH)D with T2DM (ORs (95%CIs): 0.84 (0.81, 0.88) and 0.97 (0.96, 0.99)) were observed, whereas serum 25(OH)D₃ was negatively correlated to T2DM only in the quartile 2 (Q2) and Q3 groups (both p < 0.05). The lipid profile, mainly TC and TG, partly mediated the relationship between 25(OH)D₂ or total 25(OH)D and IFG or T2DM and the proportion explained was from 2.74 to 17.46%. Furthermore, interactive effects of serum 25(OH)D₂, total 25(OH)D, and testosterone on T2DM were observed in females (both p for interactive <0.05), implying that the positive association between serum testosterone and T2DM was vanished when 25(OH)D₂ was higher than 10.04 ng/mL or total 25(OH)D was higher than 40.04 ng/mL. Therefore, ensuring adequate vitamin D levels could reduce the prevalence of IFG and T2DM, especially in females with high levels of testosterone.

Role of Vitamin D Supplementation in Heart Failure Patients With Vitamin D Deficiency and Its Effects on Clinical Outcomes: A Literature Review

Vitamin D deficiency has become a global pandemic affecting approximately one billion people worldwide. Much attention has been paid to the association of low serum 25-hydroxyvitamin D (25(OH)D) levels and various chronic diseases, especially heart failure (HF). A clear role of vitamin D deficiency has been established, with increased mortality and morbidity in heart failures. However, previous randomized control trials have failed to show improvement in clinical outcomes with calciferol supplementation in these patients. Therefore, it is still unclear whether calciferol therapy can be added to the standard care in congestive heart failure (CHF) patients with deficiency. Hence, to evaluate the role of vitamin D supplementation in CHF patients with low serum 25(OH)D, we conducted an extensive search in the PubMed and Google Scholar databases using various combinations of keywords. All potentially eligible studies that evaluated the effects of vitamin D supplementation on clinical outcomes in HF patients were retrieved and extensively studied. We also checked the references of all eligible studies to identify additional relevant publications. In this study, we reviewed various mechanisms of vitamin D affecting the cardiovascular system and examined the impact of deficiency on heart failures in terms of mortality and hospitalizations. In conclusion, vitamin D supplementation has failed to improve the clinical outcomes in HF patients. The possible long-term benefits of supplementation cannot be excluded. Therefore, for future clinical trials, we recommend considering large sample sizes, longer follow-up durations, along with optimal dosage and appropriate dosing frequency.

Is vitamin D deficiency related to a higher risk of hospitalization and mortality in veterans with heart failure?

OBJECTIVES

25-hydroxyvitamin D [25(OH)D] deficiency is related to an increase in cardiovascular risk but the association between low 25(OH)D and hospitalization and mortality in heart failure (HF) patients remains unclear. The objective of this study was therefore to determine whether 25(OH)D deficiency is associated with a higher risk of all-cause hospitalizations and mortality in veterans with HF, as well as the differential effect of frailty.

STUDY DESIGN

A retrospective cohort study of veterans with HF.

MAIN OUTCOME

Association between 25(OH)D deficiency and risk of hospitalization and mortality.

MEASURES

25(OH)D status was dichotomized as deficiency (<30 ng/mL) and non-deficiency (≥30 ng/mL). A 44-item Frailty Index (FI) was constructed and used to categorize patients as non-frail (FI < .21) or frail (FI ≥ .21). The association of 25(OH)D deficiency with recurrent hospitalization was analyzed through an Andersen-Gill model and the association with mortality using Cox regression.

RESULTS

We identified 284 patients, of whom 141 (50 %) exhibited 25(OH)D deficiency (67.3 ± 10.5 years of age). The mean 25(OH)D levels in the deficiency and non-deficiency groups were 21.3±5.9 ng/mL and 40.9 ± 10.9 ng/mL, respectively. Over a median follow-up of 1136 days (IQR = 691), there were 617 hospitalizations (68 % in those with 25(OH)D deficiency) and 131 deaths (40 % in those with 25(OH)D deficiency). A significantly higher risk of hospitalization was found in patients with 25(OH)D deficiency: hazard ratio (HR) = 1.8 (95 % CI:1.3-2.5),p < 0.001. Frail veterans had a greater risk of hospitalization than non-frail veterans: HR = 1.7 (95 % CI:1.2-2.7),p < 0.05. Mortality did not show any significant association with 25(OH)D deficiency.

CONCLUSIONS

25(OH)D deficiency was an independent risk factor for hospitalization in patients with HF and the effect persisted in those with frailty.

25-Hydroxyvitamin D level, vitamin D intake, and risk of stroke: A dose-response meta-analysis

BACKGROUND & AIMS

A growing number of studies have shown that vitamin D are related to the risk of stroke, however, the dose-response association between vitamin D and the risk of stroke is still unclear. Accordingly, we conducted a dose-response meta-analysis to evaluate the relationships between 25-hydroxyvitamin D [25(OH)D] level, vitamin D intake, and the risk of stroke by summarizing cohort studies.

METHODS

PubMed, Embase, Cochrane and the Web of Science database were searched for related studies. Cohort studies examining the influence of 25(OH)D level and vitamin D intake on stroke risk were summarized. Dose-response relationships were determined using a random-effect model.

RESULTS

Twenty cohort studies involving 217,235 participants were included. The pooled relative risk for the high-versus-low categories was 0.74 (95% CI: 0.66-0.83) for 25(OH)D level, and 0.75 (95% CI: 0.57-0.98) for vitamin D intake. In addition, there were non-linear relationships between 25(OH)D level, vitamin D intake, and stroke risk. The incidence of stroke was reduced to its lowest point, with a reduction of about 20%, when 25(OH)D level was about 50 nmol/L or vitamin D intake was about 12 μg/day.

CONCLUSION

25(OH)D level and vitamin D intake were both inversely related to stroke risk, with a non-linear dose-response relationship.