Abstract
Glioblastoma is a highly aggressive brain tumor with poor prognosis. Epidemiological studies suggest lifestyle factors, including tea intake, might influence glioblastoma risk. This study investigates the causal relationship between tea intake and glioblastoma risk using 2-sample Mendelian randomization (MR) analysis. Summary data from genome-wide association studies were used for MR analysis, employing single nucleotide polymorphisms (SNPs) associated with tea intake as instrumental variables. The causal effect of tea intake on glioblastoma risk was estimated using inverse-variance weighted (IVW), MR-Egger, weighted mode, and weighted median methods. Heterogeneity and pleiotropy were assessed using Cochran Q test and MR-Egger regression intercept. Forty SNPs were identified as instrumental variables. The IVW method showed no evidence of a causal association between tea intake and glioblastoma risk (OR = 0.6; 95% CI = 0.02-18.21; P = .7768). Supplementary analyses using MR-Egger, weighted median, and weighted mode methods were consistent with the IVW results. Leave-one-out analysis confirmed result stability, and the funnel plot indicated no pleiotropy. This MR analysis does not support a causal relationship between tea intake and glioblastoma risk. Rigorous methods are crucial for assessing causality in observational studies. Further research is needed to explore the impact of tea intake on glioblastoma using diverse study designs.