title: Prospective study of the association between sleep-disordered breathing and hypertension.
abstract: BACKGROUND
  Sleep-disordered breathing is prevalent in the general population and has been linked to chronically elevated blood pressure in cross-sectional epidemiologic studies. We performed a prospective, population-based study of the association between objectively measured sleep-disordered breathing and hypertension (defined as a laboratory-measured blood pressure of at least 140/90 mm Hg or the use of antihypertensive medications).
  
  
  METHODS
  We analyzed data on sleep-disordered breathing, blood pressure, habitus, and health history at base line and after four years of follow-up in 709 participants of the Wisconsin Sleep Cohort Study (and after eight years of follow-up in the case of 184 of these participants). Participants were assessed overnight by 18-channel polysomnography for sleep-disordered breathing, as defined by the apnea-hypopnea index (the number of episodes of apnea and hypopnea per hour of sleep). The odds ratios for the presence of hypertension at the four-year follow-up study according to the apnea-hypopnea index at base line were estimated after adjustment for base-line hypertension status, body-mass index, neck and waist circumference, age, sex, and weekly use of alcohol and cigarettes.
  
  
  RESULTS
  Relative to the reference category of an apnea-hypopnea index of 0 events per hour at base line, the odds ratios for the presence of hypertension at follow-up were 1.42 (95 percent confidence interval, 1.13 to 1.78) with an apnea-hypopnea index of 0.1 to 4.9 events per hour at base line as compared with none, 2.03 (95 percent confidence interval, 1.29 to 3.17) with an apnea-hypopnea index of 5.0 to 14.9 events per hour, and 2.89 (95 percent confidence interval, 1.46 to 5.64) with an apnea-hypopnea index of 15.0 or more events per hour.
  
  
  CONCLUSIONS
  We found a dose-response association between sleep-disordered breathing at base line and the presence of hypertension four years later that was independent of known confounding factors. The findings suggest that sleep-disordered breathing is likely to be a risk factor for hypertension and consequent cardiovascular morbidity in the general population.
authors.affiliation: Department of Preventive Medicine, University of Wisconsin School of Medicine, Madison 53705, USA. ppeppard@facstaff.wisc.edu
authors.forename: P E
authors.initials: PE
authors.lastname: Peppard
authors.forename: T
authors.initials: T
authors.lastname: Young
authors.forename: M
authors.initials: M
authors.lastname: Palta
authors.forename: J
authors.initials: J
authors.lastname: Skatrud
mesh_terms: D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000209:etiology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011446:Prospective Studies; D012891:Sleep Apnea Syndromes / Q000150:complications*