Adverse Life Events as a Potential Cause of Premature Ovarian Insufficiency: A Novel, Mixed-Methods Study

Abstract

Background: Premature ovarian insufficiency (POI) has serious physical and psychological consequences due to estrogen deprivation, leading to increased morbidity and mortality. Previous research has predominately focused on genetic, autoimmune, iatrogenic and infectious factors. However, the causes of most POI cases remain unknown. This is the first study to explore adverse life events as a potential cause of POI disease. Methods: A novel, mixed-methods study was conducted in an obstetric and gynecologic hospital located in Shanghai between 2018 and 2019. In the qualitative component, we recruited women newly- diagnosed with idiopathic POI (FSH levels >40 IU/L) in the hospital to participate in semi-structured interviews through convenience sampling. The main questions covered by the topic guide were designed to explore adverse life events prior to POI diagnosis. Data was audio recorded and transcribed verbatim before thematic analysis using QDA Miner Lite. Quantitatively, we then evaluated genome-wide patterns of DNA methylation in whole blood-derived DNA obtained from a sub-sample comprising the interview participants diagnosed with POI (n=20, mean age=34 years) and healthy women (comparison group) with regular menstrual cycles and a FSH level <8.8 IU/L (n=20, mean age= 34 years) using an Illumina850K microarray. Finally, a theoretical disease model was proposed by integrating findings of qualitative and quantitative studies. Findings: A total of 43 women (mean age=33·8 years) participated in the qualitative study. A number of stressful life events prior to POI diagnosis were discussed by them as important factors influencing their health and well-being. Three core themes emerged: 1) persistent exposure to workplace stress. 2) persistent exposure to family-related adverse life events, and 3) sleep problem/disturbance. In the quantitative study, we found that genome wide DNA-methylation profiles of patients with POI were different from women who experienced regular menses. Our analysis identified 5,582 differential methylated sites (DMSs), including 4,722 hypermethylated sites and 860 hypomethylated sites. Functional enrichment analysis identified differentially methylated sites (DMSs) were significantly associated with genes related to “stress response” and “circadian entrainment pathway”. An explanatory disease model was proposed to illustrate that long-term cumulative adverse experiences might interact with various genetic alterations and play a role in pathogenesis of POI. Interpretation: Persistent exposures to adverse life events related to work stress, family stress and sleep disturbance exist in idiopathic POI patients. The altered DNA methylation in POI patients who experienced adverse life events indicates that social adversity may affect ovarian function through a genetic process. Future research should investigate how social environmental factors influence POI disease risks, and whether provision of tailored interventions (i.e. preventing or mitigating impact of adverse life events) aimed at high-risk populations may help prevent new POI cases and improve conditions of existing POI patients. Funding Statement: This study was supported by National Key Research and Development Program of China (No.2018YFC1004800, 2018YFC1004802); The National Natural Science Foundation of China (No. 81971334); The Shanghai Municipal Education Commission—Gaofeng Clinical Medicine (No. 20152236). Declaration of Interests: All authors declare no competing interests. Ethics Approval Statement: Ethical approval was obtained from International Peace Maternity and Child Health Hospital (IPMCH) Ethic Committee.