Sleep loss and daytime sleepiness in the general adult population of Japan

There are few epidemiological studies on sleep loss and daytime sleepiness in the general adult population of Japan. A total of 4000 adult people, age d 20 and over, were randomly drawn from five areas of Japan, and 3030 indiv iduals were interviewed and completed a questionnaire including information about sleep duration and sleep problems. Overall, 29% slept less than 6 h at night, 23% reported having insufficient sleep, and 6% took sleep enhanci ng medications. The prevalence rates were 21% for symptoms of insomnia and 15% for excessive daytime sleepiness. Symptoms of insomnia were more preval ent in the elderly, whereas young people were more likely to report short s leep duration, subjective insufficient sleep and excessive daytime sleepine ss. A multiple logistic regression model revealed that excessive daytime sl eepiness had significant associations with young people, short sleep durati on, insomnia symptoms, subjective insufficient sleep and sleep enhancing me dication use. Short sleep duration was the strongest predictor of excessive daytime sleepiness. The findings indicate that sleep loss and excessive da ytime sleepiness in the Japanese adult population are common, and comparabl e to those reported in Western countries. Excessive daytime sleepiness in t he general adult population seems more likely to be attributed to short sle ep duration. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.