title: The relation between habitual sleep duration and blood pressure values in Japanese male subjects.
abstract: BACKGROUND
  Previous studies have demonstrated that sleep duration is closely associated with metabolic risk factors. However, the relationship between habitual sleep duration and blood pressure values in Japanese population has not been fully established.
  
  
  METHODS
  We performed a cross-sectional study of 1,670 Japanese male subjects to clarify the relationship between habitual sleep duration and blood pressure values. The study subjects were divided into four groups (<6, 6-, 7-, and ≥8 h) according to their nightly habitual sleep duration.
  
  
  RESULTS
  The rate of subjects with <6, 6-, 7-, and ≥8 h sleep duration was 12.0, 37.6, 38.2, and 12.2 %, respectively. Compared with the group with 7-h sleep duration (referent), the <6 and ≥8 h groups had significantly greater systolic and diastolic blood pressure values. The rate of hypertensive subjects, defined as systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg, with sleep duration of <6, 6-, 7-, and ≥8 h was 13.4, 5.7, 7.5, and 13.8 %, respectively. Compared with the group with 7-h sleep duration (referent), the multivariate odds ratios (95 % confidence interval) of the groups with <6 and ≥8 h for hypertension was 2.43 (1.40-4.20, P < 0.01) and 2.28 (1.31-3.95, P < 0.01), respectively, adjusted for conventional cardiovascular risk factors.
  
  
  CONCLUSIONS
  The present study demonstrates that both long and short habitual sleep duration were significantly associated with high blood pressure values and hypertension occurrence in Japanese male subjects.
authors.affiliation: Department of Clinical Management and Informatics, Hokkaido Information University, 59-2 Nishi-Nopporo, Ebetsu, Hokkaido 069-8585, Japan. h-satoh@do-johodai.ac.jp
authors.forename: Hiroki
authors.initials: H
authors.lastname: Satoh
authors.forename: Jun
authors.initials: J
authors.lastname: Nishihira
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Wada
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fujii
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsutui
mesh_terms: D000328:Adult; D001794:Blood Pressure; D003430:Cross-Sectional Studies; D006801:Humans; D006973:Hypertension / Q000453:epidemiology* / Q000209:etiology; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015995:Prevalence; D012307:Risk Factors; D012890:Sleep; D013997:Time Factors