Association between vitamins and risk of brain tumors: A systematic review and dose-response meta-analysis of observational studies

• Published in: Frontiers in Nutrition
• Main Authors: Weichunbai Zhang, Jing Jiang, Yongqi He, Xinyi Li, Shuo Yin, Feng Chen, Wenbin Li
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2022
• Subjects: vitamin; brain tumor; meta-analysis; β-carotene; folate; observational study; Nutrition. Foods and food supply; TX341-641; Greenland
• Online Access: https://doi.org/10.3389/fnut.2022.935706; https://doaj.org/article/f25cba647fcb4636b4d32b9949bd1c68

BackgroundBrain tumor is one of the important causes of cancer mortality, and the prognosis is poor. Therefore, early prevention of brain tumors is the key to reducing mortality due to brain tumors.ObjectiveThis review aims to quantitatively evaluate the association between vitamins and brain tumors by meta-analysis.MethodsWe searched articles on PubMed, Cochrane Library, Web of Science, and Embase databases from inception to 19 December 2021. According to heterogeneity, the fixed-effects model or random-effects model was selected to obtain the relative risk of the merger. Based on the methods described by Greenland and Longnecker, we explored the dose-response relationship between vitamins and the risk of brain tumors. Subgroup analysis, sensitivity analysis, and publication bias were also used for the analysis.ResultsThe study reviewed 23 articles, including 1,347,426 controls and 6,449 brain tumor patients. This study included vitamin intake and circulating concentration. For intake, it mainly included vitamin A, vitamin B, vitamin C, vitamin E, β-carotene, and folate. For circulating concentrations, it mainly included vitamin E and vitamin D in the serum (25-hydroxyvitamin D and α-tocopherol). For vitamin intake, compared with the lowest intakes, the highest intakes of vitamin C (RR = 0.81, 95%CI:0.66–0.99, I2 = 54.7%, Pfor heterogeneity = 0.007), β-carotene (RR = 0.78, 95%CI:0.66–0.93, I2 = 0, Pfor heterogeneity = 0.460), and folate (RR = 0.66, 95%CI:0.55–0.80, I2 = 0, Pfor heterogeneity = 0.661) significantly reduced the risk of brain tumors. For serum vitamins, compared with the lowest concentrations, the highest concentrations of serum α-tocopherol (RR = 0.61, 95%CI:0.44–0.86, I2 = 0, Pfor heterogeneity = 0.656) significantly reduced the risk of brain tumors. The results of the dose-response relationship showed that increasing the intake of 100 μg folate per day reduced the risk of brain tumors by 7% (P−nonlinearity = 0.534, RR = 0.93, 95%CI:0.90–0.96).ConclusionOur analysis suggests that the intake of ...