Tea intake and risk of allergic diseases: A Mendelian randomization study based on a European population

Some observational studies have shown that tea has some anti-allergic effects. Nevertheless, the correlation that was observed remains uncertain. We conducted a large sample two-sample Mendelian randomization (MR) study to establish the causal link between genetically predicted tea intake and allergic conditions like asthma, allergic rhinitis, chronic cough, eczema, and atopic dermatitis. In a meta-analysis of genome-wide association data from the UK Biobank, single nucleotide polymorphisms linked to tea intake were found among 447,485 individuals of European descent. Genetic information for asthma, allergic rhinitis, eczema, and atopic dermatitis was obtained from the European Bioinformatics Institute, while data for chronic cough was collected from the UK Biobank. A magnetic resonance study was carried out to investigate how certain single nucleotide polymorphisms are linked to the susceptibility of the 5 aforementioned allergic conditions. We mainly use inverse variance weighting (IVW) for initial screening. To assess multiple validity, the MR-Egger regression test was employed, while the presence of heterogeneity was examined using the Cochran Q test. To ensure the reliability of the findings, a leave-one-out analysis was conducted. IVW discovered proof of a notable cause-and-effect relationship between consuming tea and the heightened likelihood of eczema (OR = 1.009; 95% CI = 1.002-1.016; P = .016), along with a shielding element against atopic dermatitis (OR = 0.638; 95% CI = 0.456-0.895; P = .009). No diversity or multiple effects were found. This association remained strong after adjusting for potential mediators, including eosinophil counts, mood factors, and intake of other beverages. Moreover, the IVW technique in this MR analysis did not find any indication of a causal link between drinking tea and asthma, allergic rhinitis, and chronic cough (all P > .05). This research discovered that consuming tea was linked to a lower likelihood of developing atopic dermatitis but a higher likelihood of developing eczema. Additionally, the research discovered that drinking tea did not have any connection to asthma, allergic rhinitis, or chronic cough.