Isolated nocturnal hypertension and arterial stiffness in a Chinese population.

Objective: 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.

Methods: 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).

Results: 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).

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