title: Relationship between self-reported sleep quality and metabolic syndrome in general population.
abstract: BACKGROUND
  To examine an association between self-reported sleep quality determined by Pittsburgh sleep quality index (PSQI) and metabolic syndrome.
  
  
  METHODS
  This study was designed as cross-sectional study. Participants were 1481 adults aged 20 years and above from general population (549 males and 932 females). We assessed the global sleep quality by PSQI. PSQI consists of 7 elements, i.e. subjective sleep quality, sleep latency (prolonged sleep onset time), sleep duration, habitual sleep efficiency (proportion of hours slept to hours spent in bed), sleep disturbance (interruption of sleep), use of sleep medication and daytime dysfunction (trouble staying awake while engaging in social activity). Any participants with score of 6 or more are diagnosed to have sleep disorder. We also assessed the above 7 elements, which consisted of a four-grade system (i.e. 0, 1, 2, 3). Metabolic syndrome consisted of abdominal obesity, hypertension, impaired glucose tolerance and dyslipidemia. Diagnosis of metabolic syndrome was done when the participants have abdominal obesity and meet two or more other components. All analyses were adjusted by age, drinking habit, smoking habit, working hours, exercise habit and depression.
  
  
  RESULTS
  Fifty-two male participants (9.5%) and 133 female (14.3%) scored 6 or more points in global PSQI score. The global PSQI score, sleep latency score and sleep disturbance score of participants with metabolic syndrome were higher level than those without the condition (p < 0.001, p = 0.009, p = 0.025 for male and p < 0.001, p < 0.001, p = 0.002 for females, respectively). The odds ratio of metabolic syndrome among participants with PSQI score of 6 or more points were 2.37 (95% confidence interval: 1.23-4.58) for males and 2.71 (1.45-5.07) for females in contrast to those with 5 or less points. The odds ratio of metabolic syndrome with sleep latency score of 2 was 2.65 (1.14-6.15) for male and 3.82 (1.81-8.09) for females in contrast with those of 0. The odds ratio of metabolic syndrome with sleep disturbance score of 1 was 1.76 (1.09-2.86) for males and 2.43 (1.26-4.69) for females in contrast with those of 0.
  
  
  CONCLUSIONS
  Global PSQI score and its components (especially, sleep latency and sleep disturbance) were associated with metabolic syndrome.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Okubo
authors.forename: Masashi
authors.initials: M
authors.lastname: Matsuzaka
authors.forename: Ippei
authors.initials: I
authors.lastname: Takahashi
authors.forename: Kaori
authors.initials: K
authors.lastname: Sawada
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sato
authors.forename: Naoki
authors.initials: N
authors.lastname: Akimoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Umeda
authors.affiliation: Department of Social Medicine, Hirosaki University Graduate School of Medicine, 5, Zaifu-cho, Hirosaki, Aomori 036-8562, Japan. nakaji@cc.hirosaki-u.ac.jp.
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Nakaji
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications*; D008875:Middle Aged; D016017:Odds Ratio; D057566:Self Report; D012720:Severity of Illness Index; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000150:complications / Q000453:epidemiology*; D011795:Surveys and Questionnaires