Insomnia symptoms during the covid-19 pandemic: a case-control study

ABSTRACT OBJECTIVE To identify lifestyle-related, sociodemographic, and mental health characteristics of people with insomnia symptoms and people without insomnia during the pandemic. METHODS A case-control study was conducted with data collected by snowball sampling using an online questionnaire. From November 2020 to April 2021, 6,360 people with a mean age of 43.5 years (SD = 14.3) participated in the survey. For this study, we considered 158 cases of insomnia disorder and 476 controls (three controls per case) randomly selected from the participants without sleep problems. RESULTS The results of the comparative analysis between cases and controls showed that sleeping less than six hours daily (OR = 3.89; 95%CI 2.50–6.05), feeling sadness frequently (OR = 2.95; 95%CI 1.69–5.17), residing in metropolitan areas (OR = 1.71; 95%CI 1.04–2.84), being 40 years or older (OR = 1.93; 95%CI 1.22–3.06), and the interaction between occupation and poorer education (OR = 2.12; 95%CI 1.22–3.69) were predictors for symptoms of insomnia disorder during the pandemic. CONCLUSIONS In addition to confirming the hypothesis that mental health problems are associated with insomnia symptoms, the results point to insomnia as an important outcome for studies on the effects of unemployment, vulnerability and low education of the population, especially in large cities, highlighting that the effects of the crisis on health and the economy are extremely unequally distributed.

摘要 研究目的：本研究旨在明确新冠疫情期间存在失眠症状人群与无失眠人群的生活方式、社会人口学及心理健康特征。研究方法：本研究采用病例对照研究（case-control study）设计，通过滚雪球抽样（snowball sampling）结合线上问卷收集数据。2020年11月至2021年4月间，共计6360名平均年龄为43.5岁（标准差（standard deviation, SD）=14.3）的受试者参与本次调查。本研究最终纳入158例失眠障碍病例与476名对照（每例病例匹配3名对照），对照均从无睡眠问题的受试者中随机选取。研究结果：病例组与对照组的对比分析结果显示，每日睡眠不足6小时（优势比（odds ratio, OR）=3.89；95%置信区间（confidence interval, CI）2.50~6.05）、频繁感到悲伤（OR=2.95；95%CI 1.69~5.17）、居住于大都市地区（OR=1.71；95%CI 1.04~2.84）、年龄≥40岁（OR=1.93；95%CI 1.22~3.06），以及职业与低教育水平的交互作用（OR=2.12；95%CI 1.22~3.69），均为疫情期间失眠障碍症状的预测因素。研究结论：本研究不仅验证了心理健康问题与失眠症状相关的假说，同时发现失眠可作为探究失业、人群脆弱性与低教育水平影响的重要观测指标，尤其在大型城市中；研究结果同时凸显了卫生与经济危机的影响存在显著的不均等分布特征。