Vitamin D and Cardiovascular Disease: Current Evidence and Future Perspectives

Associations among vitamin D, tobacco smoke, and hypertension: A cross-sectional study of the NHANES 2001-2016

The interrelationships among vitamin D, tobacco smoking, and hypertension are currently unknown. This study was conducted to determine the relationship between vitamin D levels and hypertension and the effect of tobacco smoke exposure levels on this relationship among US adults. We performed a cross-sectional analysis of adult participants from the 2001-2016 National Health and Nutrition Examination Survey (NHANES). Serum 25-hydroxyvitamin D concentration was used as a biomarker of vitamin D status, and tobacco smoke exposure levels were objectively evaluated by serum cotinine levels. Among 22,875 eligible adults who were not receiving antihypertensive medications, the prevalence of hypertension, vitamin D deficiency (<50 mmol/L), and cotinine ≥3 ng/mL was 13.9%, 34.9%, and 29.4%, respectively. Serum cotinine and vitamin D levels were independently associated with hypertension risk after controlling for confounders (P < 0.05). When stratified by the cotinine group (<0.05, 0.05-3 and ≥3 ng/mL), we found that the risk of hypertension associated with vitamin D deficiency was higher among subjects with cotinine levels ≥3 ng/mL compared with the other strata [OR (95% CI) 1.30 (1.09, 1.54) vs. 1.53 (1.19, 1.96) vs. 1.64 (1.30, 2.06); P for heterogeneity test <0.05]. Furthermore, serum cotinine levels were negatively correlated with vitamin D levels. These findings suggested that the increased risk of hypertension could be partly attributed to low vitamin D levels induced by tobacco smoke exposure, in addition to the effects of tobacco smoke exposure and vitamin D deficiency themselves.

Evidence of a casual relationship between vitamin D deficiency and hypertension: a family-based study

An association between vitamin D deficiency and hypertension has been observed in numerous studies. However, blood pressure improvements resulting from supplementation with vitamin D have been inconsistent. The causal relationship between vitamin D deficiency and hypertension is still unclear and was investigated in this family-based study. A total of 1370 individuals from both vitamin D deficiency and hypertension families were included. First, the heritability of vitamin D deficiency was estimated by the Falconer method. Second, SNPs (single nucleotide polymorphisms) of vitamin D metabolic and functional pathway genes associated with vitamin D deficiency were screened by a family-based association test, and the findings were further verified in nuclear families with vitamin D deficiency. Finally, a family-based association test was applied to investigate the association between selected SNPs associated with vitamin D deficiency and hypertension. The heritability of vitamin D deficiency was 50.4% in this family-based study. Allele C of rs3847987 was a risk factor for vitamin D deficiency (OR: 1.639, 95% CI: 1.170-2.297, P = 0.004). Furthermore, a family-based association of rs3847987 with hypertension was found in both additive and recessive models (P < 0.05). In addition, vitamin D deficiency was associated with hypertension (OR: 1.317, 95% CI: 1.022-1.698, P = 0.033). In conclusion, rs3847987 in the VDR gene was associated with both vitamin D deficiency and hypertension. Therefore, vitamin D deficiency may be a causal factor for hypertension.

Predictive value of 25-hydroxyvitamin D level in patients with coronary artery disease: A meta-analysis

Background

A consensus has not been made about the predictive value of blood vitamin D level in patients with coronary artery disease (CAD). This meta-analysis aimed to assess the association between blood 25-hydroxyvitamin D level and adverse outcomes in patients with CAD.

Methods

Two independent authors searched the articles indexed in PubMed and Embase databases until June 28, 2022. Cohort studies or post-hoc analysis randomized trials evaluating the value of 25-hydroxyvitamin D level in predicting cardiovascular or all-cause mortality, and major adverse cardiovascular events ([MACEs] including death, non-fatal myocardial infarction, heart failure, revascularization, stroke, etc.) were included.

Results

The literature search identified 13 eligible studies for our analysis, including 17,892 patients with CAD. Meta-analysis showed that the pooled adjusted risk ratio (RR) was 1.60 (95% confidence intervals [CI] 1.35–1.89) for all-cause mortality, 1.48 (95% CI 1.28–1.71) for cardiovascular mortality, and 1.33 (95% CI 1.18–1.49) for MACEs. Leave-out one study sensitivity analysis suggested that the predictive values of blood 25-hydroxyvitamin D level were reliable.

Conclusions

Low blood 25-hydroxyvitamin D level is possibly an independent predictor of cardiovascular or all-cause mortality and MACEs in patients with CAD. Baseline 25-hydroxyvitamin D level may provide useful information in CAD patients.

Is vitamin D deficiency a risk factor for all-cause mortality and rehospitalization in heart failure patients?: A systematic review and meta-analysis

OBJECTIVE

The association of low 25-hydroxyvitamin D level with mortality and rehospitalization remains inconsistent in patients with heart failure. This systematic review and meta-analysis aimed to evaluate the value of blood 25-hydroxyvitamin D level in predicting all-cause mortality and hospitalization in heart failure patients.

METHODS

Two reviewers independently search the articles indexed in PubMed and Embase databases until November 30, 2021. Only the prospective or retrospective cohort studies evaluating the association of blood 25-hydroxyvitamin D level with all-cause mortality and rehospitalization in heart failure patients were selected. The predictive value of 25-hydroxyvitamin D level was summarized by pooling multivariable adjusted risk estimates for the bottom versus reference top 25-hydroxyvitamin D level.

RESULTS

Seven studies with a total of 5941 patients with heart failure were identified. The pooled adjusted risk ratio (RR) of all-cause mortality was 1.37 (95% confidence interval [CI] 1.13-1.66), with significant heterogeneity (I2 = 70.5%; P = 0.002). However, there was no clear association between low 25-hydroxyvitamin D level and all-cause rehospitalization risk (RR 1.38; 95% CI 0.87-2.19).

CONCLUSIONS

Low blood level of 25-hydroxyvitamin D may be an independent risk factor for all-cause mortality in patients with heart failure. Serum 25-hydroxyvitamin D level may provide prognostic information in heart failure patients. Additional randomized controlled trials are required to explore whether treatment of 25-hydroxyvitamin D deficiency by supplementation of vitamin D can improve survival in heart failure patients.

Circulating Vitamin D Concentrations and Risk of Atrial Fibrillation: A Mendelian Randomization Study Using Non-deficient Range Summary Statistics

Background and Aims

Vitamin D deficiency is a common disorder and has been linked with atrial fibrillation (AF) in several observational studies, although the causal relationships remain unclear. We conducted a Mendelian randomization (MR) analysis to determine the causal association between serum 25-hydroxyvitamin D [25(OH)D] concentrations and AF.

Methods and Results

The analyses were performed using summary statistics obtained for single-nucleotide polymorphisms (SNPs) identified from large genome-wide association meta-analyses conducted on serum 25(OH)D (N = 79,366) and AF (N = 1,030,836). Six SNPs related to serum 25(OH)D were used as instrumental variables. The association between 25(OH)D and AF was estimated using both the fixed-effect and random-effects inverse variance weighted (IVW) method. The MR analyses found no evidence to support a causal association between circulating 25(OH)D level and risk of AF using random-effects IVW (odds ratio per unit increase in log 25(OH)D = 1.003, 95% CI, 0.841–1.196; P = 0.976) or fixed-effect IVW method (OR = 1.003, 95% CI, 0.876–1.148; P = 0.968). Sensitivity analyses yielded similar results. No heterogeneity and directional pleiotropy were detected.

Conclusion

Using summary statistics, this MR study suggests that genetically predicted circulating vitamin D concentrations, especially for a non-deficient range, were not causally associated with AF in the general population. Future studies using non-linear design and focusing on the vitamin D deficiency population are needed to further evaluate the causal effect of vitamin D concentrations on AF.

The Role of Vitamin D3 as an Independent Predicting Marker for One-Year Mortality in Patients with Acute Heart Failure

Background: Deficiency in vitamin D3 and its metabolites has been linked to dismal outcomes in patients with chronic diseases, including cardiovascular disease and heart failure (HF). It remains unclear if a vitamin D3 status is a prognostic feature in patients with acute decompensated HF. Methods: We assessed serum levels of 25-OH-vitamin D3 and 1,25-(OH)2-vitamin D3 in 139 patients with acute HF who had been admitted to the intermediate care unit of a maximum care hospital. The follow-up period was one year. After exclusion of patients with sampling errors and those who were lost to follow-up, 118 patients remained in the final study cohort. Outcome estimates by 25-OH-vitamin D3 and 1,25-(OH)2-vitamin D3 levels were compared to the Seattle Heart Failure (SHF) Model. Results: More than two-thirds (79.7%) of the patients showed inadequate 25-OH-vitamin D3 levels (i.e., <30 ng/mL) upon admission. Low levels of 1,25-(OH)2-vitamin D3 (i.e., <19.9 pg/mL) were observed in 16.1% of patients. Of the 118 HF patients, 22 (19%) died during the following 12 months. There were no differences in vitamin D3 levels between patients who died and those who survived, neither in 25-OH-vitamin D3 (23.37 ± 19.14 ng/mL vs. 19.11 ± 12.25 ng/mL; p = 0.19) nor in 1,25-(OH)2-vitamin D3 levels (31.10 ± 19.75 ng/mL vs. 38.25 ± 15.73 ng/mL; p = 0.02); therefore, vitamin D3 levels alone did not predict one-year survival (AUC [25-OH-vitamin D3] 0.50; 95% CI 0.34−0.65; AUC [1,25-(OH)2-vitamin D3] 0.62; 95% CI 0.48−0.76). Moreover, whilst the SHF model exhibited acceptable discriminatory ability for predicting one-year mortality (AUC 0.79; 95% CI 0.66−0.91), adding vitamin D levels on admission to the SHF score did not improve its discriminatory value. Conclusion: Our data do not support the use of vitamin D3 screening in patients admitted with acute decompensated HF to aid prognostication.

Vitamin D supplementation and postoperative atrial fibrillation

Vitamin D is an important vitamin that has hormone-like effects in the human body. 1,25-dihydroxy vitamin D (1,25(OH)2 D) is known as the active form of vitamin D. Activated vitamin D can affect cellular proliferation, apoptosis, cellular membrane transport, immune system, and aging through genes. Postoperative atrial fibrillation (PoAF) is an important problem that increases mortality and morbidity rates after cardiac surgery operations. Various studies have been conducted on the relationship between vitamin D and PoAF. Although there are studies in the literature showing that vitamin D supplementation reduces cardiovascular mortality and morbidity in different study types (randomized vs. observational), there are also studies showing that it has no effect on clinical outcomes. Since the subject is atrial fibrillation, the conditions of the study groups such as age, the prevalence of coronary artery disease, degree of hypertension, and lung disease should be analyzed well. On the other hand, vitamin D supplementation should be carefully determined for which patient, for how long, and at what dose.

Small Differences in Vitamin D Levels between Male Cardiac Patients in Different Stages of Coronary Artery Disease

Cardiovascular diseases are the main cause of mortality in males older than 65 years of age. The prevalent vitamin D deficiency in the worldwide population may have multiple effects on the cardiovascular system. This study sought to determine the association between serum levels of 25-hydroxyvitamin D (25(OH)D) and the stage of coronary artery disease (CAD) in Polish male subjects. Additionally, subjects with a history of myocardial infarction (MI) were analyzed for potential differences in 25(OH)D levels in comparison with those diagnosed with stable CAD. The study was conducted prospectively in a group of 669 male patients subjected to coronarography examination. CAD stage was defined using the Coronary Artery Surgery Study Score. Patients without significant coronary lesions had significantly higher 25(OH)D levels than patients with single-, double-, or triple-vessel disease (median, 17 vs. 15 ng/mL; p < 0.01). Significantly lower levels of 25(OH)D were apparent when MI was identified as the cause of the then-current hospitalization in comparison with stable CAD, as well as in patients with a history of MI; all of these cases had lower levels of 25(OH)D in comparison with patients with no such history. Male patients with single-, double-, or triple-vessel CAD, acute coronary syndrome, or a history of MI presented lower serum 25(OH)D.