To investigate the association between ambulatory blood pressure (BP) variables (level, short-term variability, circadian variation and morning pressor surge) and carotid artery alteration in a general population.
We measured ambulatory BP every 30 min in 775 participants (mean age 66.2 ± 6.2 years, 68.8% women) from the Japanese general population. Short-term BP variability during the daytime and night-time were estimated as within-subject standard deviation of daytime and night-time BP, respectively. Circadian BP variation was calculated as the percentage decline in nocturnal BP. Morning pressor surge was defined as morning BP minus pre-waking BP. The extent of carotid artery alteration was evaluated as the average of common carotid intima–media thickness (IMT) and the presence of focal carotid plaque.
Daytime and night-time BP values were more closely associated with carotid artery alteration than casual BP. With mutual adjustment for daytime and night-time BP, the latter (P < 0.0001) was more closely associated with IMT, which represents diffuse arterial thickening and arteriosclerosis, than daytime BP (P = 0.2). Night-time systolic BP variability was positively associated with carotid plaque (focal atherosclerotic lesions) independently of possible confounding factors, including night-time systolic BP (P = 0.01). A diminished nocturnal decline in systolic BP was associated with a greater IMT after adjustment for confounding factors (P = 0.03). A morning pressor surge was not associated with carotid artery alteration.
Ambulatory BP levels and BP variability were closely associated with carotid artery alteration, suggesting that these parameters are independent risk factors or predictors of carotid artery alteration.
aDepartments of Clinical Pharmacology and Therapeutics, Japan
bPlanning for Drug Development and Clinical Evaluation, Japan
cEnvironmental Health Sciences, Tohoku University Graduate School of Pharmaceutical Sciences and Medicine, Sendai, Japan
dTohoku University 21st Century COE Program ‘Comprehensive Research and Education Center for Planning of Drug Development and Clinical Evaluation’, Sendai, Japan
eOhasama Hospital, Iwate, Japan
Received 5 October, 2006
Revised 8 February, 2007
Accepted 15 March, 2007
Correspondence to Masahiro Kikuya, Departments of Clinical Pharmacology and Therapeutics, Tohoku University Hospital, Sendai, 1-1 Seiryo-cho, Aoba-ku, Sendai, 980-8574, Japan Tel: +81 22 717 8590; fax: +81 22 717 8591; e-mail: email@example.com