Association between alopecia areata, anxiety, and depression: Insights from a bidirectional two-sample Mendelian randomization study

As research progresses, there has been growing interest in the association between Alopecia areata (AA) and anxiety, as well as depression. However, there have been limited reports on the genetic variation level of AA in relation to mental disorders. We performed large-scale Two sample Mendelian randomization (MR) analyses to examine whether there is a association between AA with anxiety and depression. The data utilized for AA analysis were sourced from the FinnGen release 9 databases, including 682 cases and 361,822 controls. Summary statistics for major depression disorder (MDD) were obtained from a genome-wide meta-analysis dataset, incorporating 170,756 cases and 329,443 controls. The anxiety disorder data was conducted by the Anxiety Neuro Genetics Study Consortium, including 5580 cases and 11,730 controls. We employed four distinct approaches, including MR-Egger, weighted median, random-effect inverse variance weighted (IVW), and weighted mode, to conduct the MR analysis. Genetic liability to AA was associated with an increased risk of Major depression disorder (MDD) and anxiety demonstrated an odds ratio (OR) of 1.01 (βivw = 0.011, PIVW = 0.023) and OR of 1.16 (βivw = 0.150, PIVW = 0.002). Upon conducting the Bonferroni correction, the P-values were 0.046 and 0.004, respectively. For reverse analysis, we observed no significant association between anxiety and MDD with the risk of AA. Our research unveil a unidirectional causal association whereby AA exerts a risk effect against MDD and anxiety, which serves as a valuable complement to prior meta-analyses, enriching the existing body of knowledge on the subject matter.