Heartache and Heartbreak: An Observational and Mendelian Randomization Study.

Background: Depression has a significant effect on cardiovascular disease (CVD), but uncertainties persist regarding which modifiable risk factors mediate the causal effects. We aim to determine whether depression is causally linked to CVD and which modifiable risk factors play potential mediating roles. Methods: We used a two-sample Mendelian randomization (MR) approach and NHANES 2007-2018 data to estimate the effects of depression on various CVD cases and investigated 28 potential mediators of the association between depression and CVD. Results: The results of our MR analysis indicated that genetically determined depression was associated with increased risk of several CVD, including coronary heart disease (odds ratio (OR) = 1.14; 95% confidence interval (CI): 1.05,1.22), myocardial infarction (OR = 1.19; 95% CI, 1.09,1.31), atrial fibrillation (OR = 1.14; 95% CI, 1.06,1.22), and stroke (OR = 1.13; 95% CI, 1.05,1.22). However, there was no causal association between depression and heart failure. Four out of 28 cardiometabolic risk factors, including hyperlipidemia, hypertension, diabetes, and prescription opioid use, were identified as mediators of the association between depression and various CVDs. Observational association analyses from NHANES data yielded consistent results. Conclusion: Our findings demonstrated that depression has a causal detrimental effect on various CVDs. Four causal mediators (hyperlipidemia, hypertension, diabetes, and prescription opioid use) were screened to explain the causal effect. Implementing targeted management strategies for these risk factors may be warranted to mitigate the public health burden of CVD among individuals with depression.