Supplementary Material for: Potential correlation between tea intake and the risk of amyotrophic Lateral Sclerosis: A Mendelian randomization study

Introduction: There were limited observation studies on the association between tea intake and amyotrophic lateral sclerosis (ALS) with inconsistent results. This study aimed to determine the potential relationship between tea intake and ALS by a two-sample Mendelian randomization (MR) analysis.
Methods: We identified 41 independent SNPs strongly associated with tea intake from 448,060 participants of European ancestry in the UK Biobank. Summary statistics associated with ALS were also obtained from the UK Biobank including 20,806 cases and 59,804 controls. The study used MR analysis to assess the potential effect of tea consumption on ALS, and several methods such as sensitivity analyses and MR-pleiotropy residual sum and outlier (MR-PRESSO) method were performed to further test the robustness of our findings.
Results: The F statistic was more than 10 in each SNP, which meets the first assumption for the MR study. Using the Inverse variance weighted (IVW) MR analysis as the primary method, we found that a one standard deviation increase in tea consumption was associated with a 14% lower risk of ALS (OR=0.86, 95%CI=0.74-0.99, P＜0.05). Sensitivity analyses detected no potential pleiotropy and directional heterogeneity.
Conclusion: Our MR study supported the potential relationship between tea intake and ALS risk, suggesting the potential advantages of tea intake for preventing ALS. Future clinical trials and research are needed to further validate the results and elucidate possible mechanisms.