1.
Vitamin B12, B6, or Folate and Cognitive Function in Community-Dwelling Older Adults: A Systematic Review and Meta-Analysis.
Zhang, C, Luo, J, Yuan, C, Ding, D
Journal of Alzheimer's disease : JAD. 2020;(2):781-794
Abstract
BACKGROUND Previous studies have indicated that B vitamin deficiencies are an essential cause of neurological pathology. There is a need to provide evidence of the benefit of B vitamins for the prevention of cognitive decline in community-dwelling older adults. OBJECTIVE To examine the association between intake and plasma levels of vitamins B12, B6, and folate and cognitive function in older populations through a systematic review and meta-analysis. METHODS Medline (PubMed), EMBASE, and Cochrane databases were used to search the literature though August 8, 2019. We included observational population-based studies evaluating the association between concentrations or intake levels of vitamins B6, B12, or folate and cognition in older adults aged ≥45 years. The quality of all studies was assessed by the modified Newcastle-Ottawa Scale. Odds ratios (ORs) and hazard ratios (HRs) were analyzed by the random-effects model. Sensitivity analyses were conducted by excluding the studies with significant heterogeneity. RESULTS Twenty-one observational studies with sample sizes ranging from 155-7030 were included in the meta-analysis. Higher levels of vitamin B12 (OR = 0.77, 95% CI = 0.61-0.97) and folate concentration (OR = 0.68, 95% CI = 0.51-0.90) were associated with better cognition in cross-sectional studies, but not in sensitivity analyses or prospective studies. High vitamin B6 concentrations showed no significant benefit on cognition and dementia risk. Prospective studies did not provide substantial evidence for the relationship. CONCLUSION The results from our meta-analysis suggest that vitamins B12, B6, and folate may not be modifiable risk factors for slowing cognitive decline among community-dwelling older individuals.
2.
Association Between One-carbon Metabolism-related Vitamins and Risk of Breast Cancer: A Systematic Review and Meta-analysis of Prospective Studies.
Zeng, J, Gu, Y, Fu, H, Liu, C, Zou, Y, Chang, H
Clinical breast cancer. 2020;(4):e469-e480
Abstract
Epidemiologic studies focusing on the association between 1-carbon metabolism-related vitamins (ie, folate, vitamin B6, vitamin B2, vitamin B12) and breast cancer risk have reported inconsistent findings. We conducted a systematic search of the reported data and performed a meta-analysis of prospective case-control and cohort studies to derive a more precise evaluation. The PubMed and EMBASE databases were searched to identify eligible studies. A total of 27 studies involving 49,707 cases and 1,274,060 individuals were included in the meta-analysis. The results indicated that a high intake of folate, vitamin B6, and vitamin B2 might decrease the risk of breast cancer. The corresponding pooled relative risks (RRs) for the highest intake compared with the lowest were 0.93 (95% confidence interval [CI], 0.88-0.99; P = .018), 0.94 (95% CI, 0.89-1.00; P = .037) and 0.90 (95% CI, 0.82-0.99; P = .026). No significant association between vitamin B12 and breast cancer risk was found (RR, 0.99; 95% CI, 0.94-1.04; P = .604). Further study showed that folate and vitamin B6 might decrease the risk of estrogen receptor-negative (ER-)/progesterone receptor-negative (PR-) breast cancer but not ER+/PR+ breast cancer. The dose-response meta-analysis indicated a significant linearity relationship between folate intake and a reduced risk of ER-/PR- breast cancer. An increment of folate intake (100 μg/d) corresponded to a 7% deceased risk of ER-/PR- breast cancer (RR, 0.93; 95% CI, 0.89-0.98; P = .007). In conclusion, a high intake of 1-carbon metabolism-related vitamins might contribute to the prevention of breast cancer, especially ER-/PR- breast cancer.
3.
Intake of vitamin B6, folate, and vitamin B12 and risk of coronary heart disease: a systematic review and dose-response meta-analysis of prospective cohort studies.
Jayedi, A, Zargar, MS
Critical reviews in food science and nutrition. 2019;(16):2697-2707
Abstract
The objective of this study was to quantify the association of B-vitamins intake with the future risk of coronary heart disease (CHD). A systematic search was performed with the use of PubMed and Scopus from inception to April 30, 2018. Prospective cohort studies evaluating the association of intake of folate, vitamin B6, and vitamin B12 with risk of CHD in the general population were included. A random-effects meta-analysis was performed. Eleven prospective cohort studies (total n = 369,746) with 5133 cases of CHD were included in the analyses. The relative risks were: 0.79 (95%CI: 0.69, 0.89; I2 = 67%) for a 250 µg/d increment in folate intake; 0.87 (95%CI: 0.78, 0.96; I2 = 80%) for a 0.5 mg/d increment in vitamin B6 intake; and 0.97 (95%CI: 0.80, 1.14: I2 = 67%) for a 3 µg/d increment in vitamin B12 intake. The results did not change materially when the analyses were restricted only to dietary vitamins intake. A nonlinear dose-response meta-analysis demonstrated a linear inverse association between folate and vitamin B6 intake and risk of CHD. In conclusion, higher intake of folate and vitamin B6 is associated with a lower risk of CHD in the general population.
4.
Vitamin B6 Intake and Pancreatic Carcinoma Risk: A Meta-Analysis.
Peng, YF, Han, MM, Huang, R, Dong, BB, Li, L
Nutrition and cancer. 2019;(7):1061-1066
Abstract
Objectives: There are conflicting results for the association between vitamin B6 intake with reduced pancreatic carcinoma risk. Thus, a meta-analysis was performed to summarize the evidences from epidemiological studies. Methods: We searched documents from PubMed-Medline, Web of Science, and Cochrane Library. The results were analyzed by using Stata software. Results: A total of nine studies were included. The multivariate-adjusted results found that the total RR values of pancreatic carcinoma was 0.65 (95% CI: 0.53-0.80) for the highest vitamin B6 intake vs the lowest vitamin B6 intake, and there was no significant heterogeneity among studies (I2 = 42.0%, P = 0.087). Sensitivity analysis indicated that no single study leaded to an excessive change for the relation between vitamin B6 intake and pancreatic carcinoma risk. Conclusions: This meta-analysis suggested that vitamin B6 intake could significantly decrease pancreatic carcinoma risk. However, further study is needed based on the limitations of the current analysis.