遗传工具变量筛选标准：全基因组显著性SNP选择与偏倚控制方法

2.2 Selection Criteria To screen for genetic instrumental variables related to exposure factors, we adopted the following criteria: (1) selecting single-nucleotide polymorphisms (SNPs) that are associated with each exposure factor at a genome-wide significant level (P < 5 × 10⁻⁸); (2) excluding SNPs with linkage disequilibrium to ensure that the instrumental variables are independent (r² < 0.01, clustering window = 10,000 kb); (3) removing medium-frequency palindromic SNPs that may cause ambiguity in allele strand assignment and calculating the F statistic to assess the strength of the instrumental variables, ensuring that the F statistic > 10 to exclude weak instrument bias.