ASSOCIATION BETWEEN INSOMNIA AND DEPRESSION AND RISK OF ALL-CAUSE MORTALITY: A POPULATION-BASED PROSPECTIVE COHORT STUDY

초록

Introduction: The purpose of this study was to investigate the association of insomnia and depression, both independently and combined, on long-term mortality. This study was conducted based on 20 years follow-up data from a population-based cohort study in Korea, namely the Korean Genome and Epidemiology Study (KoGES). Materials and methods: Participants (n=3,357; mean age 48.7 ± 7.6; females 45.2%) completed self-report questionnaires including demographic information (age, sex, marital status, education, monthly family income), lifestyle (smoking, alcohol use, exercise), medical history (cancer, cardiovascular disease, hyperlipidemia, diabetes), insomnia symptoms (difficulty initiating sleep, difficulty maintaining sleep, early morning awakening) and depressive symptoms using Beck Depression Inventory-I (BDI-I). All data was collected biannually from 2001 to 2020. Mortality data were collected from the Statistics Korea (KOSTAT) and combined with the original dataset. Participants who reported more than one of the three symptoms of insomnia at least three times a week, more than three months (or at both baseline and 1st follow-up) were classified into the Insomnia group. Participants with a score of 24 or more on the BDI-I were classified into the Depression group. Cox proportional hazards model using Python (“Lifelines” package) was conducted to predict mortality using the following four groups classified at baseline: no insomnia or depression (Healthy), Insomnia-only, Depression-only, and Both-Insomnia-and-Depression group. Results: After controlling for covariates (demographic factors, lifestyle, medical history), the differences of hazard ratio (HR) for all-cause mortality were significant among groups. Specifically, the HR for all-cause mortality of the Insomnia-only group was 1.7 times higher than the Healthy group (HR, 1.74; 95% CI, 1.19-2.55; p=.005). The HR for the Both-Insomnia-and-Depression group for all-cause mortality was 3.8 times higher than the Healthy group (HR, 3.77; 95% CI, 1.60-8.88; p=.002). There was no difference in HR for the Depression-only group and Healthy group for all-cause mortality. Conclusions: The Insomnia only group and the combined Insomnia and Depression group had a significantly elevated likelihood of mortality compared to the Healthy group in a 20-year follow-up study. Notably, insomnia, a risk factor for several mental and physical illnesses, was found to be associated with higher mortality in this study. This study provides additional evidence for the association between insomnia and all-cause mortality.