title: Prevalence and correlates of nonrestorative sleep complaints.
abstract: BACKGROUND
  Nonrestorative sleep (NRS) has been little studied in the general population, even though this symptom has an important role in several medical conditions such as heart disease, fibromyalgia, and chronic fatigue syndrome, as well as various sleep disorders.
  
  
  METHODS
  A total of 25,580 individuals (age range, 15-100 years) from the noninstitutionalized general population representative of 7 European countries (France, the United Kingdom, Germany, Italy, Portugal, Spain, and Finland) were interviewed by telephone using the Sleep-EVAL system. Nonrestorative sleep was analyzed in relationship to sociodemographic determinants, environmental factors, life habits, health, sleep-wake schedule, and psychological factors.
  
  
  RESULTS
  The prevalence of NRS was 10.8% (95% confidence interval, 10.4%-11.2%) in the sample, was higher in women than in men (12.5% vs 9.0%; P<.001), and decreased with age. The United Kingdom (16.1%) and Germany (15.5%) had the highest prevalence of NRS and Spain (2.4%), the lowest. In multivariate analyses, several factors were positively associated with NRS. The most important were younger age, dissatisfaction with sleep, difficulty getting started in the morning, stressful life, presence of anxiety, bipolar or a depressive disorder, and having a physical disease. When compared with subjects who have difficulty initiating or maintaining sleep (without NRS), subjects with NRS reported more frequently a variety of daytime impairment (irritability, physical, and mental fatigue) and consulted a physician twice as frequently for their sleeping difficulties than did other subjects with insomnia.
  
  
  CONCLUSIONS
  Nonrestorative sleep is a frequent symptom in the general population, but its prevalence largely varies between countries. It is often associated with mental disorders and characteristics of sleep deprivation (such as extra sleep time on weekends). Nonrestorative sleep affected more frequently the active classes of the population and caused greater daytime impairment than difficulty initiating or maintaining sleep.
authors.affiliation: Stanford Sleep Epidemiology Research Center, Stanford University School of Medicine, Stanford, Calif., USA. mohayon@stanford.edu
authors.forename: Maurice M
authors.initials: MM
authors.lastname: Ohayon
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005387:Finland / Q000453:epidemiology; D005602:France / Q000453:epidemiology; D005858:Germany / Q000453:epidemiology; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008019:Life Style; D016015:Logistic Models; D008297:Male; D001523:Mental Disorders / Q000150:complications; D008875:Middle Aged; D011174:Portugal / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors; D012892:Sleep Deprivation / Q000453:epidemiology* / Q000209:etiology* / Q000523:psychology; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology* / Q000209:etiology*; D013030:Spain / Q000453:epidemiology; D013315:Stress, Psychological / Q000150:complications; D006113:United Kingdom / Q000453:epidemiology