Objective:To investigate the relationship between different types of tea intake and COVID-19 infection.Methods:Data were retrieved from a genome-wide association study(GWAS),involving 447 485,and 64 949 people for single nucleotide polymorphisms(SNPs).Two-sample Mendelian randomization(MR)analysis was used to investigate the relationship of different types of tea intake with four subgroups of COVID-19 infected population,including COVID-19 infected population versus general population,COVID-19 hospitalized population versus general population,COVID-19 hospitalized population versus non-hospitalized population,and very severe respiratory confirmed population versus general population.Inverse-variance weighted(IVW)method was used as the main method of causal analysis.MR Egger intercept was used for pleiotropy test,and Cochran's Q-statistic was used for heterogeneity test.Results:Compared to the general population,tea intake decreased the incidence of COVID-19 in the infection population(IVW method,OR=0.806,95%CI:0.651-0.999),and the hospitalized population(IVW method,OR=0.533,95%CI:0.369-0.770).Additionally,the underlying pleiotropy was not found following the MR-Egger regression intercept(MR intercept=-0.002,P=0.667),and the Cochran's Q-statistic showed no heterogeneity(Q-statistic=52.712,P=0.057).Compared to the general population,the underlying pleiotropy in the hospitalized patients was not found by MR-Egger regression intercept(MR intercept=-0.001,P=0.909),and the Cochran's Q-statistic showed no heterogeneity(Q-statistic=25.214,P=0.945).However,green tea and herbal tea had no effect on COVID-19 infection.Conclusions:Overall tea intake reduces the risk of COVID-19 infection in the general population compared to COVID-19 infected and hospitalized populations,while green tea and herbal tea have no protective effect against COVID-19 infection.

Objective:To investigate the relationship between different types of tea intake and COVID-19 infection.Methods:Data were retrieved from a genome-wide association study(GWAS),involving 447 485,and 64 949 people for single nucleotide polymorphisms(SNPs).Two-sample Mendelian randomization(MR)analysis was used to investigate the relationship of different types of tea intake with four subgroups of COVID-19 infected population,including COVID-19 infected population versus general population,COVID-19 hospitalized population versus general population,COVID-19 hospitalized population versus non-hospitalized population,and very severe respiratory confirmed population versus general population.Inverse-variance weighted(IVW)method was used as the main method of causal analysis.MR Egger intercept was used for pleiotropy test,and Cochran's Q-statistic was used for heterogeneity test.Results:Compared to the general population,tea intake decreased the incidence of COVID-19 in the infection population(IVW method,OR=0.806,95%CI:0.651-0.999),and the hospitalized population(IVW method,OR=0.533,95%CI:0.369-0.770).Additionally,the underlying pleiotropy was not found following the MR-Egger regression intercept(MR intercept=-0.002,P=0.667),and the Cochran's Q-statistic showed no heterogeneity(Q-statistic=52.712,P=0.057).Compared to the general population,the underlying pleiotropy in the hospitalized patients was not found by MR-Egger regression intercept(MR intercept=-0.001,P=0.909),and the Cochran's Q-statistic showed no heterogeneity(Q-statistic=25.214,P=0.945).However,green tea and herbal tea had no effect on COVID-19 infection.Conclusions:Overall tea intake reduces the risk of COVID-19 infection in the general population compared to COVID-19 infected and hospitalized populations,while green tea and herbal tea have no protective effect against COVID-19 infection.

【Objective】To evaluate the treatment effect of maxillary protraction on skeletal class Ⅲ high angle cases in mixed dentition.【Methods】Nine patients were treated with combined posterior occlusal acrylic and maxillary protraction.The cephalometric radiographs were analyzed before and after the treatment.【Results】The maxilla and maxillary dentitions moved forward.Overjet increased by 4.18mm (P<0.001).The anterior and posterior total face height increased.The maxilla and mandible showed no significant rotation.Profiles were improved to some extent.【Conclusion】A combined posterior occlusal acrylic and maxillary protraction can correct the sagittal maxillo-madibular interrelationships,with no unfavourable influence on facial vertical dimension.But the treatment does not change the vertical skeletal pattern.