Tea consumption and cancer: a Mendelian randomization study / 中华流行病学杂志

Objective: A Mendelian randomization (MR) analysis was performed to assess the relationship between tea consumption and cancer. Methods: There were 100 639 participants with the information of gene sequencing of whole genome in the China Kadoorie Biobank. After excluding those with cancer at baseline survey, a total of 100 218 participants were included in this study. The baseline information about tea consumption were analyzed, including daily tea consumption or not, cups of daily tea consumption, and grams of daily tea consumption. We used the two-stage least square method to evaluate the associations between three tea consumption variables and incidence of cancer and some subtypes, including stomach cancer, liver and intrahepatic bile ducts cancer, colorectal cancer, tracheobronchial and lung cancer, and female breast cancer. Multivariable MR and analysis only among nondrinkers were used to control the impact of alcohol consumption. Sensitivity analyses were also performed, including inverse variance weighting, weighted median, and MR-Egger. Results: We used 54, 42, and 28 SNPs to construct non-weighted genetic risk scores as instrumental variables for daily tea consumption or not, cups of daily tea consumption, and grams of daily tea consumption, respectively. During an average of (11.4±3.0) years of follow-up, 6 886 cases of cancer were recorded. After adjusting for age, age2, sex, region, array type, and the first 12 genetic principal components, there were no significant associations of three tea consumption variables with the incidence of cancer and cancer subtypes. Compared with non-daily tea drinkers, the HR (95%CI) of daily tea drinkers for cancer and some subtypes, including stomach cancer, liver and intrahepatic bile ducts cancer, colorectal cancer, tracheobronchial and lung cancer, and female breast cancer, are respectively 0.99 (0.78-1.26), 1.17 (0.58-2.36), 0.86 (0.40-1.84), 0.85 (0.42-1.73), 1.39 (0.85-2.26) and 0.63 (0.28-1.38). After controlling the impact of alcohol consumption and performing multiple sensitivity analyses, the results were similar. Conclusion: There is no causal relationship between tea consumption and risk of cancer in population in China.

Associations between vitamin D levels and systemic lupus erythematosus risk:a Mendelian randomized study / 中华预防医学杂志

Objective: To explore the causal effects of the serum Vitamin D levels on the risk of systemic lupus erythematosus (SLE). Methods: A two-sample Mendelian randomization (MR) study was performed to infer the causality. Three Genome-wide association studies (GWAS) for circulating Vitamin D levels, including 25-hydroxyvitamin D [25(OH)D], 25-hydroxyvitamin D3 [25(OH)D3] and C3-epimer of 25-hydroxyvitamin D3 [C3-epi-25(OH)D3] published in 2020, and one GWAS for SLE published in 2015 were utilized to analyze the causal effects of the serum Vitamin D levels on the risk of SLE. MR analyses were conducted using the inverse-variance weighted method (IVW), weighted median, MR-Egger methods, MR-pleiotropy residual sum and outlier (MR-PRESSO) method. Results: 34, 29 and 6 SNPs were respectively selected as instrumental variables to analyze the causal association of total 25 (OH) D level, 25 (OH) D3 level and C3-epi-25 (OH) D3 level with the risk of SLE. The MR results showed that each standard deviation decrease in the level of 25(OH)D3 would result in 14.2% higher risk of SLE (OR, 0.858; 95%CI, 0.753-0.978; P=0.022). The levels of 25(OH)D and C3-epi-25(OH)D3 had null associations with risk of SLE (OR, 0.849; 95%CI, 0.653-1.104; P=0.222; OR, 0.904; 95%CI, 0.695-1.176; P=0.452). Conclusion: This study have identified a causal effect of 25(OH)D3 on increased risk of SLE. These findings highlighted the significance of active monitoring and prevention of SLE in population of low Vitamin D levels.

Estimación del aislamiento genético e ilegitimidad en 60 comunidades hondureñas mediante el análisis de apellidos / Estimation of genetic isolation and illegitimacy in 60 Honduran communities by means of surname analysis

Antecedentes: La búsqueda de aislamientos genéticos, i.e. poblaciones humanas aisladas, es importante para la salud pública puesto que la endogamia aumenta la prevalencia de enfermedades mendelianas. Además, la frecuencia de alelos deletéreos en general podría verse aumentada por efecto fundador y deriva génica. El aislamiento genético puede ser estimado mediante análisis de las proporciones de apellidos con las técnicas de isonimia.Objetivos: Determinar la estructura genética aproximada, la presencia de aislamientos genéticos y la proporción de hijos ilegítimos mediante el análisis de frecuencias de apellidos e isonimia en 60 comunidades de cinco municipios rurales Hondureños.Método: Los apellidos se obtuvieron de la base de datos del TSE. Se determinaron los coeficientes de endogamia FST, FIT y FIS a partir de las proporciones de apellidos por los métodos matemáticos descritos por Crowy Mange. Se calculó la tasa de ilegitimidad como la proporción de sujetos con un solo apellido. Resultados: Las comunidades más aisladas fueron las del municipio de Trinidad, seguidas por Orica. Las menos aisladas correspondieron a los municipios de predominio afrodescendiente. Orica presentó la tasa de ilegitimidad más elevada. Discusión: El método de isonimia utilizado reveló la presencia de aislamientos genéticos que deberán ser estudiados más a fondo desde el punto de vista de la epidemiología genética. La diversidad encontrada en las comunidades afrodescendientes tiene como origen la contribución anglosajona. La alta proporción de ilegitimidad en Orica podría estar relacionada con paternidad irresponsable y bajo estatus socioeconómico con consecuencias adversas para el bienestar social y la salud pública...