Isolated nocturnal hypertension and arterial stiffness in a Chinese population

We reported previously that normotensive Chinese had higher nighttime diastolic blood pressure (BP) compared with non-Chinese. We, therefore, studied the prevalence and characteristics of isolated nocturnal hypertension and its association with arterial stiffness, an intermediate sign of target organ damage.

We recorded ambulatory BP, the central and peripheral systolic augmentation indexes, the ambulatory arterial stiffness index, and brachial-ankle pulse wave velocity in 677 Chinese enrolled in the JingNing population study (53.6% women; mean age: 47.6 years).

The prevalence of isolated nocturnal hypertension (> or = 120/70 mmHg from 22 : 00 to 4 : 00 h) was 10.9%. Patients with isolated nocturnal hypertension, compared with participants with ambulatory normotension (45.8%), were older (53.7 vs. 40.7 years), more often reported alcohol intake (68.9 vs. 51.0%), and had faster nighttime pulse rate (62.8 vs. 60.7 bpm), higher serum cholesterol (5.12 vs. 4.77 mmol/l), and higher blood glucose (4.84 vs. 4.38 mmol/l). They also had higher indexes of arterial stiffness (P<0.05) than participants with ambulatory normotension. Of 74 patients with isolated nocturnal hypertension, only four (5.4%) had hypertension on conventional office BP measurement (> or = 140/90 mmHg).

Isolated nocturnal hypertension can only be diagnosed by ambulatory BP monitoring, is prevalent among Chinese, and is associated with increased arterial stiffness.