Prevalence of isolated systolic hypertension in Chinese adult population

OBJECTIVE: To evaluate prevalence of isolated systolic hypertension and other subtypes of hypertension, as well as their distribution in Chinese adults. METHODS: A cross-sectional survey was conducted in the mainland China during 2000-2001 with a multistage cluster sampling to select a nationally representative sample of 15,540 Chinese adults aged 35-74, by InterASIA project. Hypertension subtypes were defined among individuals not receiving antihypertensive therapy as follows: isolated systolic hypertension as a systolic blood pressure > or = 140 mm Hg and a diastolic blood pressure < 90 mm Hg, isolated diastolic hypertension as a systolic pressure < 140 mm Hg and a diastolic pressure > or = 90 mm Hg, and combined systolic/diastolic hypertension as a systolic pressure > or = 140 mm Hg and a diastolic pressure > or = 90 mm Hg. Blood pressure for each subject was measured for three readings at sitting position after rest for at least five minutes and an average reading was recorded. A standardized structured questionnaire was used to collect history of hypertension and antihypertensive treatment. RESULTS: Overall, 7.6% (1,181 cases) of adults had isolated systolic hypertension, 7.4% (1,150 cases) combined systolic/diastolic hypertension and 4.4% (683 cases) isolated diastolic hypertension in the sample of 15,540 adults at age 35-74. Prevalence of systolic hypertension increased with age, and was more common in the older women than in the older men. There was no significant difference in prevalence of isolated systolic hypertension between north and south China, but, rural residents had a higher prevalence than urban residents. CONCLUSION: There existed a higher prevalence of systolic hypertension in China, to which enough attention should be paid.