Causal effects of COVID-19 on structural changes in specific brain regions: a Mendelian randomization study.

Background: Previous studies have found a correlation between coronavirus disease 2019 (COVID-19) and changes in brain structure and cognitive function, but it remains unclear whether COVID-19 causes brain structural changes and which specific brain regions are affected. Herein, we conducted a Mendelian randomization (MR) study to investigate this causal relationship and to identify specific brain regions vulnerable to COVID-19.

Methods: Genome-wide association study (GWAS) data for COVID-19 phenotypes (28,900 COVID-19 cases and 3,251,161 controls) were selected as exposures, and GWAS data for brain structural traits (cortical thickness and surface area from 51,665 participants and volume of subcortical structures from 30,717 participants) were selected as outcomes.

Causal relationship between gastroesophageal reflux disease, Barrett's esophagus, and epilepsy: A bidirectional Mendelian randomization study.

Background: The incidence of gastroesophageal reflux disease (GERD) has been shown to be elevated in individuals with epilepsy. Traditional observational studies have led to a limited understanding of the effects of GERD and BE on epilepsy due to the interference of reverse causation and potential confounders.

Methods: We conducted a bidirectional two-sample Mendelian randomization (MR) analysis to determine whether GERD and BE can increase the risk of epilepsy.