Abstract
Insomnia is a growing health concern globally, which can obstruct daytime functionality, reduce overall quality of life, and result in various diseases including depression, anxiety disorders and cardiovascular diseases. Increasing literature have focused on the potential role of ambient temperature in sleep problems, but the association remains inconclusive. This study aimed to explore a short-term association of ambient temperature with emergency department (ED) visits for insomnia in the capital city of South Korea. Using the National Emergency Department Information System database from 2008 to 2017, 7,855 patients who visited ED for insomnia (International Classification of Disease, 10th revision code F51.0 and G47.0) were identified. A time-stratified case-crossover design was employed using a conditional logistic regression model. A distributed lag non-linear model was utilized to explore potential non-linear and lag effects of ambient temperature on ED visits for insomnia. Odds ratio (OR) for temperature with maximum ED visits for insomnia (MaxIT) and that for temperature with minimum ED visits for insomnia (MinIT) were calculated and compared. A significant association was found between ambient temperature and ED visits for insomnia. Total insomnia increased significantly at a high temperature (MaxIT: 29.3℃, OR: 2.09 [95% CIs: 1.43–3.04]) compared to that at a MinIT (-8.9℃). Furthermore, the association between high temperature and insomnia was found to be stronger in females, 35–49 age group, and patients without comorbidities. The risk of insomnia is significantly increased in high ambient temperature. Our findings provide insights for proactive public health strategies for managing insomnia during global temperature rise.