[Bidirectional causal relationship between glucose-lipid metabolism, obesity indicators, and myocardial infarction: a bidirectional Mendelian randomization analysis study].

<b>Objective:</b> To explore the causal association of glucose-lipid metabolism and obesity indicators with myocardial infarction by a two-sample Mendelian randomization analysis. <b>Methods:</b> Single nucleotide polymorphisms (SNPs) related to phenotypes were obtained from genome-wide association study databases. The body mass index (BMI) and glycated hemoglobin dataset includes 99 998 samples and 8 126 035 SNPs; the waist-to-hip ratio dataset includes 224 459 samples and 2 562 516 SNPs; the waist circumference and hip circumference dataset includes 462 166 samples and 9 851 867 SNPs; the fasting glucose dataset includes approximately 12 million SNPs; the low-density lipoprotein cholesterol (LDL-C) dataset includes 201 678 samples and 12 321 875 SNPs; the high-density lipoprotein cholesterol (HDL-C), and triglycerides dataset includes 156 109 samples and 15 784 414 SNPs; and the body fat percentage, whole-body fat mass, trunk fat percentage, and trunk fat mass dataset includes 454 588 samples and 9 851 867 SNPs. This study primarily used inverse-variance weighted method to analyze the associations between various exposure factors and outcomes. Heterogeneity among SNPs was assessed using Cochran's <i>Q</i> test, and horizontal pleiotropy of SNPs was examined using the MR-Egger method. Additionally, a multivariable MR approach was used to adjust for BMI, further validating associations between exposure factors and the risk of myocardial infarction. <b>Results:</b> Higher BMI (<i>OR=</i>1.070, 95%<i>CI</i>: 1.041-1.100), waist-to-hip ratio (<i>OR</i>=1.366, 95%<i>CI</i>: 1.113-1.677), LDL-C (<i>OR</i>=1.638, 95%<i>CI</i>: 1.488-1.803), triglycerides (<i>OR</i>=1.445, 95%<i>CI</i>: 1.300-1.606), waist circumference (<i>OR</i>=1.841, 95%<i>CI</i>: 1.650-2.055), hip circumference (<i>OR</i>=1.247, 95%<i>CI</i>: 1.132-1.372), body fat percentage (<i>OR</i>=1.795, 95%<i>CI</i>: 1.568-2.055), whole-body fat mass (<i>OR</i>=1.519, 95%<i>CI:</i> 1.381-1.670), trunk fat percentage (<i>OR</i>=1.538, 95%<i>CI</i>: 1.374-1.723), and trunk fat mass (<i>OR</i>=1.421, 95%<i>CI</i>: 1.294-1.561), as well as lower HDL-C (<i>OR</i>=0.799, 95%<i>CI</i>: 0.729-0.875), have causal effects on myocardial infarction (all <i>P</i><0.05). After adjusting for BMI, hip circumference, trunk fat percentage, and trunk fat mass were no longer associated with myocardial infarction. However, waist-to-hip ratio (<i>OR</i>=1.457, 95%<i>CI</i>: 1.132-1.877), fasting glucose (<i>OR</i>=1.191, 95%<i>CI</i>: 1.024-1.383), glycated hemoglobin (<i>OR</i>=1.129, 95%<i>CI</i>: 1.034-1.233), LDL-C (<i>OR</i>=1.592, 95%<i>CI</i>: 1.314-1.929), triglycerides (<i>OR</i>=1.410, 95%<i>CI</i>: 1.279-1.553), waist circumference (<i>OR</i>=1.922, 95%<i>CI</i>: 1.448-2.551), body fat percentage (<i>OR</i>=1.421, 95%<i>CI</i>: 1.072-1.884), and whole-body fat mass (<i>OR</i>=1.295, 95%<i>CI</i>: 1.031-1.626) remained positively associated with myocardial infarction, while HDL-C (<i>OR</i>=0.809, 95%<i>CI</i>: 0.729-0.897) remained negatively associated. <b>Conclusions:</b> Abdominal obesity and dysregulation of glucose-lipid metabolism are risk factors for myocardial infarction. Screening for glucose-lipid metabolism (fasting glucose, HDL-C, LDL-C, triglycerides) and obesity-related indicators (waist circumference, waist-to-hip ratio, body fat percentage, and whole-body fat mass) is of great importance for the primary prevention of myocardial infarction.