Objective and Self‐Reported Sleep Duration
All participants in the present study underwent electroencephalography‐based overnight unattended polysomnography (P‐Series, Compumedics) at their residence. The sleep monitor was set up by trained and certified technicians. Objective sleep duration, acquired from the polysomnography records, was defined as the total sleep time consisting of rapid eye movement sleep and non‐REM sleep. If the polysomnography monitoring was inadequate, a repeat monitoring request was initiated (Data Self‐reported sleep duration was obtained from sleep habit questionnaires such as “How many hours of sleep do you usually get at night (or What time do you usually fall asleep and wake up) on weekdays or workdays?” and “How many hours of sleep do you usually get at night (or What time do you usually fall asleep and wake up) on weekends or your nonworkdays?” We also collected the sleep duration from the morning survey based on the question “How long did you sleep last night?” Sleep duration was further categorized as ≤4 hours, 4 to 5 hours, 5 to 6 hours, 6 to 7 hours, 7 to 8 hours, and >8 hours in this study.