title: An epidemiological study of insomnia among the Japanese general population.
abstract: The study examined the prevalence and correlates of insomnia in a representative sample (n=3030) from the general population of Japan. Using a structured questionnaire, we found that the overall prevalence of insomnia during the preceding month was 21.4%, including difficulty initiating sleep (DIS: 8.3%), difficulty maintaining sleep (DMS: 15.0%), and early morning awakening (EMA: 8.0%). Multiple logistic regression analysis showed that older age, being unemployed, lack of habitual exercise, poor perceived health, psychological stress, and being unable to cope with stress were associated with an increased prevalence of insomnia. These findings indicate that the prevalence of insomnia in the general population of Japan is comparable to that reported in Western countries, and that insomnia is associated with multiple psychosocial factors.
authors.affiliation: Department of Psychophysiology, National Institute of Mental Health, NCNP, Ichikawa-city, Chiba, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kim
authors.forename: M
authors.initials: M
authors.lastname: Uchiyama
authors.forename: M
authors.initials: M
authors.lastname: Okawa
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.forename: R
authors.initials: R
authors.lastname: Ogihara
mesh_terms: D000328:Adult; D000368:Aged; D003431:Cross-Cultural Comparison; D003430:Cross-Sectional Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008019:Life Style; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012307:Risk Factors; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology* / Q000209:etiology; D013315:Stress, Psychological / Q000150:complications