Unveiling Depression as a Significant Cause of Insomnia through NHANES Database and Mendelian Randomization Analysis

Abstract

Background: Despite the existence of shared pathophysiological risk factors, the connection between depression and insomnia remains enigmatic. This research aims to provide empirical evidence to clarify this association through a meticulous analysis using data obtained from the 2005–2008 National Health and Nutrition Examination Survey (NHANES) combined with Mendelian randomization (MR) techniques. Methods: Examining the connection between depression and insomnia, we utilized data from the NHANES spanning 2005 to 2008. Employing a two-sample Mendelian randomization (MR) approach with genome-wide association study (GWAS) summary statistics, our study sought to unveil potential causal relationships between depressive symptoms and insomnia. The analysis utilized the original inverse variance weighting (IVW) method along with other MR techniques to validate the established causal association. Furthermore, a multivariate MR analysis was conducted, simultaneously considering multiple variables to comprehensively explore the interplay between depression and insomnia. Results: Our investigation, encompassing 7,463 participants from the National Health and Nutrition Examination Survey (NHANES), utilized weighted multivariable-adjusted logistic regression. The analysis unveiled a significant positive correlation between depressive symptoms and the odds ratio (OR) of insomnia, with an effect estimate of 4.157 (95% CI, 3.449–5.022). Mendelian randomization (MR) analysis further substantiated a causal link, showing an OR of 1.375 (95% CI, 1.313 ~ 1.440) for the association between depression and insomnia. Even after excluding potential confounding variables in the multivariate MR analysis, the consistent findings bolster the credibility of evidence supporting the causal relationship. Sensitivity analyses, with a non-significant p-value (P > 0.05), underscore the robustness of the observed relationship. Conclusion The presence of depression increases the likelihood of experiencing insomnia.