title: Enhanced sodium sensitivity and disturbed circadian rhythm of blood pressure in essential hypertension.
abstract: OBJECTIVE
  To assess whether an association between sodium-sensitive hypertension and metabolic syndrome exists; and whether, in patients with metabolic syndrome, the nocturnal fall of blood pressure decreases and salt restriction affects the circadian blood pressure rhythm.
  
  
  METHODS
  Japanese patients with essential hypertension, who were treated without any antihypertensive agent, were maintained on a high-sodium diet and a low-sodium diet for 1 week each. On the last day of each diet, the 24-h blood pressures were measured. A diagnosis of metabolic syndrome was made according to the International Diabetes Foundation definition
  
  
  RESULTS
  Among the 56 patients with essential hypertension, 15 patients were complicated with metabolic syndrome while 41 patients were not. The nocturnal blood pressure fall was significant in patients without metabolic syndrome, while it was not so in patients with metabolic syndrome. Only in patients with metabolic syndrome was the nocturnal blood pressure fall enhanced by sodium restriction. The prevalence of sodium-sensitive hypertension in patients with metabolic syndrome was significantly higher than in those without metabolic syndrome (70.6 versus 36.0%, respectively; P = 0.017). A multiple logistic regression analysis revealed central obesity to be an independent risk factor for sodium-sensitive hypertension (odds ratio, 1.41; 95% confidence interval, 1.04-1.91).
  
  
  CONCLUSIONS
  In patients with essential hypertension, an inter-relationship exists among metabolic syndrome, enhanced sodium sensitivity of the blood pressure and non-dipping. The elevated risk of cardiovascular diseases in patients with metabolic syndrome may be related to sodium-sensitive hypertension and non-dipping.
authors.affiliation: Department of Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan. takuzu@belle.shiga-med.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Uzu
authors.forename: Genjiro
authors.initials: G
authors.lastname: Kimura
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamauchi
authors.forename: Masami
authors.initials: M
authors.lastname: Kanasaki
authors.forename: Keiji
authors.initials: K
authors.lastname: Isshiki
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Araki
authors.forename: Toshiro
authors.initials: T
authors.lastname: Sugiomoto
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Nishio
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Maegawa
authors.forename: Daisuke
authors.initials: D
authors.lastname: Koya
authors.forename: Masakazu
authors.initials: M
authors.lastname: Haneda
authors.forename: Atsunori
authors.initials: A
authors.lastname: Kashiwagi
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects*; D016022:Case-Control Studies; D002940:Circadian Rhythm / Q000187:drug effects*; D015986:Confounding Factors, Epidemiologic; D004039:Diet, Sodium-Restricted; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000453:epidemiology / Q000503:physiopathology*; D007564:Japan / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D024821:Metabolic Syndrome / Q000188:drug therapy / Q000453:epidemiology / Q000503:physiopathology; D008875:Middle Aged; D009318:Natriuresis / Q000187:drug effects; D009765:Obesity / Q000188:drug therapy / Q000453:epidemiology / Q000503:physiopathology; D015995:Prevalence; D012307:Risk Factors; D012982:Sodium, Dietary / Q000008:administration & dosage*
chemical_list: D000959:Antihypertensive Agents; D012982:Sodium, Dietary