Geographic variations in the prevalence, awareness, treatment and control of hypertension in China

OBJECTIVE: To compare the prevalence, awareness, treatment and control of hypertension in north and south, and urban and rural residents of China. DESIGN: A cross-sectional survey conducted in 2000-2001. SETTING AND PARTICIPANTS: A multistage cluster sampling method was used to select a nationally representative sample of 15 540 men and women aged 35-74 years from the general Chinese population. MAIN OUTCOME MEASURES: Three blood pressure measurements were obtained by trained observers using a standardized mercury sphygmomanometer. Information on history of hypertension and use of antihypertensive medications was obtained by use of a standard questionnaire. Hypertension was defined as a mean systolic blood pressure >or= 140 mmHg and/or diastolic blood pressure >or= 90 mmHg and/or use of antihypertensive medications. RESULTS: The age-standardized prevalence of hypertension was significantly higher among residents living in north than in south China (33.8 versus 23.3%, P < 0.001), but similar in those living in urban and rural areas (29.0 versus 28.1%, P = 0.3). Average systolic and diastolic blood pressure levels were consistently higher in north than in south residents. Residents in north China had higher percentages of awareness but lower percentages of control compared with their counterparts in south China. Percentages of awareness, treatment and control of hypertension were significantly higher in urban than in rural residents. CONCLUSIONS: Our study documents a marked north-south gradient in the prevalence of hypertension in China. The previously reported urban-rural difference in the prevalence of hypertension was not noted, perhaps due to a rapid increase in the prevalence of hypertension in rural China.