Impact of negative emotions and insomnia on sepsis: A mediation Mendelian randomization study

Negative emotions and insomnia (NEI) can lead to inflammation, which is a characteristic of sepsis. However, the interaction among NEI and sepsis has not yet been proven. Therefore, Mendelian mediation was used to explore this relationship in this study. The genetic correlation NEI and sepsis was assessed by via linkage disequilibrium scores (LDSC). A two-sample Mendelian randomization (MR) study design was performed to examine the causal association between NEI and sepsis using the inverse variance weighted (IVW) method. The reliability of the results was estimated by weighted median and MR-Egger methods, but heterogeneity was evaluated via Radial and Cochran's Q tests. Biases in gene polymorphisms were checked by MR-Egger regression and MR-PRESSO. Mendelian mediation analyses were applied to quantify the intermediary effect and proportional contribution. A genetic link between sepsis and depression was determined via LDSC analysis. The relationship between depression and sepsis was revealed through MR analysis [odds ratio (OR) = 1.21, 95 % confidence interval (CI) = 1.08–1.36, p = 1.07 × 10−3)]. The results were not influenced by heterogeneity or pleiotropy biases. Chitinase 3 Like 1 (CHI3L1) was a mediator with a mediation effect size of 0.12. The ratio of the intermediated effect to total effect was 10.31 %. CHI3L1 is a key factor which mediates the interaction between NEI and sepsis.