The association of deficiencies of water-soluble vitamin intake with health-related quality of life and prognosis in patients with heart failure

Causal effects of circulating vitamin levels on the risk of heart failure: a Mendelian randomization study

BACKGROUND

Observational studies suggest inverse associations between serum vitamin levels and the risk of heart failure (HF). However, the causal effects of vitamins on HF have not been fully elucidated. Here, we conducted a Mendelian randomization (MR) study to investigate the causal associations between genetically determined vitamin levels and HF.

METHODS

Genetic instrumental variables for circulating vitamin levels, including vitamins A, B, C, D, and E, which were assessed as either absolute or metabolite levels were obtained from public genome-wide association studies. Summary statistics for single-nucleotide-polymorphisms and HF associations were retrieved from the HERMES Consortium (47,309 cases and 930,014 controls) and FinnGen Study (30,098 cases and 229,612 controls). Two-sample MR analyses were implemented to assess the causality between vitamin levels and HF per outcome database, and the results were subsequently combined by meta-analysis.

RESULTS

Our MR study did not find significant associations between genetically determined circulating vitamin levels and HF risk. For absolute vitamin levels, the odds ratio for HF ranged from 0.97 (95% confidence interval [CI]: 0.85-1.09, P = 0.41) for vitamin C to 1.05 (95% CI: 0.61-1.82, P = 0.85) for vitamin A. For vitamin metabolites, the odds ratio ranged between 0.94 (95% CI: 0.75-1.19, P = 0.62) for α-tocopherol and 1.11 (95% CI: 0.98-1.26, P = 0.09) for γ-tocopherol.

CONCLUSION

Evidence from our study does not support the causal effects of circulating vitamin levels on HF. Therefore, there may be no direct beneficial effects of vitamin intake on the prevention of primary HF.

Lack of Association between Inadequate Micronutrient Intake and Prognosis in Outpatients with Heart Failure

Inadequate nutrient intake can lead to worse outcomes in patients with heart failure (HF). This prospective cohort study aimed to assess the prevalence of inadequate micronutrient intake and their association with prognosis in 121 adult and elderly outpatients with HF. Habitual micronutrient intake was evaluated using 24-h dietary recalls (minimum 2 and maximum 6). Participants were grouped into moderate (n = 67) and high (n = 54) micronutrient deficiency groups, according to the individual assessment of each micronutrient intake. Patients' sociodemographic, clinical, and anthropometric data and clinical outcomes (hospitalization and mortality) within 24 months were collected. Overall and event-free survival rates were calculated using Kaplan-Meier estimates, and curves were compared using the log-rank test. The death risk rate (hazard ratio (HR)) was calculated using Cox's univariate model. The rate of inadequate intake was 100% for vitamins B1 and D and above 80% for vitamins B2, B9, and E, calcium, magnesium, and copper. No differences in overall survival and event-free survival were observed between groups of HF outpatients with moderate and high micronutrient deficiencies (HR = 0.94 (CI = 0.36-2.48), p = 0.91, and HR = 1.63 (CI = 0.68-3.92), p = 0.26, respectively), as well as when the inadequacy of each micronutrient intake was evaluated alone (all p > 0.05). In conclusion, a high prevalence of inadequate micronutrient intake was observed in outpatients with HF. Inadequate micronutrient intake was not associated with hospitalization and mortality in this group of patients.