摘要BACKGROUND Loneliness and isolation are associated with multiple cardiovascular diseases(CVDs),but there is a lack of research on whether they were causally linked.We conducted a Mendelian Randomization(MR)study to explore causal relation-ships between loneliness and isolation and multiple CVDs.METHODS Single nucleotide polymorphisms associated with loneliness and isolation were identified from a genome-wide as-sociation study(GWAS)of 455,364 individuals of European ancestry in the IEU GWAS database.Summary data for 15 CVDs were also obtained from the IEU GWAS database.We used three MR methods including inverse variance weighting,MR-Egger,and weighted median estimation to assess the causal effect of exposure on outcomes.Cochran's Q test and MR-Egger intercept test were used to evaluate the heterogeneity and pleiotropy.RESULTS MR analysis showed that loneliness and isolation were significantly associated with essential hypertension(OR = 1.07,95%CI:1.03-1.12),atherosclerotic heart disease(OR = 1.04;95%CI:1.02-1.06),myocardial infarction(OR = 1.02;95%CI:1-1.04)and angina(OR = 1.04;95%CI =1.02-1.06).No heterogeneity and pleiotropy effects were found in this study.CONCLUSIONS Causal relationship of loneliness and isolation with CVDs were found in this study.