Methods: Trained nurses obtained two blood pressure measurements from each
subject. Hypertension was defined as mean systolic blood pressure 4140 mmHg,
diastolic blood pressure490 mmHg, or a self-reported diagnosis of hypertension and
taking antihypertensive medication. All data were analysed using Stata 9.2 software
and took the complex survey design into account. A two-sided P-value of o0.05 was
considered to be statistically significant.