Nightime blood pressure and cardiovascular structure in a middle aged general population in northern Italy: the Vobarno study

The aim was to determine, in a cross-sectional study,
the relation between structural alterations in the heart
and carotid arteries, and blood pressure (BP) changes
from day to night time, measured by ambulatory BP
(ABP). In 225 untreated subjects (107 F, 118 M, age
range 48–64 years) and 59 treated subjects (24 M, 35 F,
age range 50–64), living in a small town of northern Italy
(Vobarno, Brescia) carotid intima media thickness as
well as the occurrence of plaque, were evaluated by
ultrasound. Echocardiographic left ventricular (LV)
mass was measured according to the Penn Convention.
BP was determined by clinic measurement and by 24-h
non-invasive ABP monitoring. Subjects were divided in
two groups, according to the decrease of night time systolic
BP (SBP) ‘dippers’ (SBP decreased by at least 10%
during night time) and ‘non-dippers’ (decrease of night
time SBP 10%). The intima-media thickness in the common carotid, in the carotid bifurcation, in the
internal carotid artery and average intima-media thickness
were significantly greater in untreated non-dippers
as compared with dipper subjects (ANOVA P 0.05). A
significantly higher prevalence of plaque was observed
in untreated non-dippers as compared with dippers (P
0.002). After adjusting for age, sex, 24-h SBP, and
smoking, IMT in the carotid bifurcation and average
intima-media thickness remained significantly greater in
non-dipper subjects (P 0.05 for all comparisons). No
significant differences in LV mass were observed
between dippers and non-dipper subjects. In conclusion,
in a general population of unselected middleaged
subjects, night time BP values, among other risk
factors, seem to represent an important determinant of
carotid wall structure.