Abstract

Tea is a natural plant with important nutritional, health and clinical value. Tea has many natural active substances, such as catechins, epigallocatechin gallate and caffeine; these chemicals have a significant effect on the human body. Recently, some studies have suggested that tea intake may be related to childhood asthma. However, the relationship between those two factors remains controversial. In this study, two-sample Mendelian randomization was used to explore the causal effects of tea intake on childhood asthma. Genome-wide association studies have provided summary data on tea consumption and childhood asthma. Various Mendelian randomization methods were employed to evaluate the findings. To test the robustness of these outcomes, we applied different methods, including Cochran's Q test, Mendelian randomization-Egger regression and Mendelian randomization pleiotropy residual sum and outlier method. We also used several methods to test for heterogeneity and horizontal pleiotropy and the results were unaffected by heterogeneity and horizontal pleiotropy. Thus, our study suggests that there is no causal relationship between tea intake and childhood asthma, but the biochemical mechanisms between them need to be further explored.