Causal relationship between mental disorders and hypercholesterolemia： a Mendelian randomization analysis

BackgroundMetabolic syndrome （MetS） is highly prevalent in patients with mental disorders， including elevated diastolic or systolic blood pressure， elevated fasting glucose， hypercholesterolemia， abdominal obesity and so on. As an important component of MetS， the relationship between hypercholesterolemia and mental disorder has been extensively reported， whereas few genome-wide association studies （GWAS） have been conducted to identify the causal role of mental disorders in hypercholesterolemia.ObjectiveTo explore the potential causal relationship between mental disorders and hypercholesterolemia by two-sample Mendelian randomization （MR） method.MethodsSummary data from GWAS were analyzed. Single nucleotide polymorphisms （SNPs） strongly associated with mental disorders were chosen as instrumental variables， and hypercholesterolemia was used as outcome variable. MR analysis utilized inverse-variance weighted （IVW）， MR-Egger regression and weighted median estimation （WME） as the primary analytical tool， and supplemented by simple mode （SM） and weighted mode （WM）. The causal relationship between mental disorders and the risk of hypercholesterolemia was illustrated in terms of odds ratio （OR）.ResultsA total of 36 SNPs associated with mental disorders were identified as instrumental variables. The primary findings from IVW revealed existence of a causal relationship between mental disorders and hypercholesterolemia （IVW： OR=1.067， 95% CI： 1.026~1.109， P=0.001）. Findings from the additional methods （MR-Egger regression， WME， SM， WM） were basically consistent with those reported in IVW method. Further verification indicated that the causal relationship between mental disorders and the risk of hypercholesterolemia was not affected by genetic polymorphism （P>0.05）. The absence of heterogeneity was confirmed through Cochran's Q test and MR-Egger regression （P>0.05）. Furthermore， no causal association in the reverse direction was found （P>0.05）.ConclusionThere is a causal relationship between mental disorders and hypercholesterolemia， and patients with mental disorders may have an increased probability of suffering from hypercholesterolemia.