title: Nocturnal decline in blood pressure is attenuated by NaCl loading in salt-sensitive patients with essential hypertension: noninvasive 24-hour ambulatory blood pressure monitoring.
abstract: We investigated the effect of NaCl on the circadian blood pressure rhythm in patients with essential hypertension classified according to the presence or absence of salt sensitivity. We obtained 24-hour noninvasive ambulatory blood pressure measurements in 64 Japanese patients with mild to moderate essential hypertension who ate a low NaCl diet (50 mmol/d) for 1 week, followed by a high NaCl diet (340 mmol/d) for 1 week. Twenty-six patients whose mean blood pressure was increased more than 10% by NaCl loading were classified as salt sensitive. The remaining 38 patients were classified as salt resistant. The nocturnal decline in mean blood pressure was significantly smaller in salt-sensitive patients (8.3+/-1.0%) than in salt-resistant patients (11.5+/-0.9%) (P<.05) during a high NaCl diet but was similar in both groups during a low NaCl diet. There was no significant difference in the prevalence of the non-dipper pattern between groups on a low NaCl diet, but the prevalence of the non-dipper pattern was significantly higher in salt-sensitive patients than in salt-resistant patients on a high NaCl diet (0.57 versus 0.26, chi2=6.4; P=.02; odds ratio, 3.82). These findings suggest that the NaCl loading blunted the nocturnal decline in blood pressure in salt-sensitive patients but not in salt-resistant patients.
authors.affiliation: First Department of Internal Medicine, Hiroshima University School of Medicine, Minami-ku, Japan. yhigashi@mcai.med.hiroshima-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Higashi
authors.forename: T
authors.initials: T
authors.lastname: Oshima
authors.forename: R
authors.initials: R
authors.lastname: Ozono
authors.forename: Y
authors.initials: Y
authors.lastname: Nakano
authors.forename: H
authors.initials: H
authors.lastname: Matsuura
authors.forename: M
authors.initials: M
authors.lastname: Kambe
authors.forename: G
authors.initials: G
authors.lastname: Kajiyama
mesh_terms: D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm; D004039:Diet, Sodium-Restricted; D004351:Drug Resistance; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012965:Sodium Chloride / Q000494:pharmacology*
chemical_list: D012965:Sodium Chloride