Sex difference of the prevalence and risk factors associated with prehypertension among urban Chinese adults from 33 communities of China: the CHPSNE study

Background: As a new category of blood pressure (BP) classification according to the Seventh Report of The Joint National Committee, prehypertension has aroused people's great concern in recent years due to its associations with increased incidence of cardiovascular disease. However, there is little information about the epidemiology of prehypertension in urban China. The aim of this study is to estimate the prevalence of prehypertension and to identify its risk factors among urban Chinese men and women. Methods: A cross-sectional survey in a representative sample of 25 196 Chinese adults aged 18-74 years was conducted in three cities of northeast of China during 2009 and 2010. Body weight, height, waist circumference, and BP were measured by trained observers. Results: Overall, the prevalence of prehypertension was 56.9%, men 71.1% and women 44.6%, respectively. Multivariate analysis revealed that higher education or a higher family income were risk factors of prehypertension among men, but shown as protective factors among women. Among men, high odds ratios (ORs) of prehypertension were found in overweight [OR 2.31; 95% confidence interval (CI) 2.02-2.71] and obese (OR 7.92, 95% CI 4.36-14.42) adults (defined as body mass index), whereas abdominal obesity (OR 2.94, 95% CI 2.48-3.57) (defined as waist circumference) was the main determinant for prehypertension status in women. Conclusion: Our results indicate that hypertension is highly prevalent in urban China and there is a sex difference in the relationships between risk factors and prehypertension.