Objective To develop a nationally acceptable blood pressure(BP)reference standards for the diagnosis and evaluation of hypertension in children and adolescents in China.Methods The current study was based on the data from eleven large-scale cross-sectional BP surveys in China's Mainland since 2001,the survey sites were representative of national geographical distribution including four municipalities(Beijing,Shanghai,Tianjin,Chongqing)and seven provinces(Hunan,Liaoning,Hebei,Zhejiang,Guangxi,Xinqiang and Guangdong).The surveys which met the following selection criteria were involved to form the reference population sample and pooled database:1)Subjects were Han nationality and their ages were from 3 to 18 years old;2)BP levels were measured by auscultation using standard sphygmomanometer and recorded as Korotkoff phase 1(SBP),Korotkoff phase 4(DBP-K4)and/or Korotkoff phase 5(DBP-K5);3)All surveyors were trained before investigations and standard quality control was implemented throughout the BP measuring process;4)Basic variables,except BPs,were at least included but not limited to age,sex,nationality,height and weight.Totally 112 227 subjects(56 912 males accounting for 50.7%)were enrolled in the reference population sample in this study.SPSS 13.0 software was used to do the descriptive statistical analysis.Centile curves for SBP,DBP-K4 and DBP-K5 were drawn by sex using LMS method.Z scores of Height and BMI were calculated based on the data from the Chinese National Survey on Constitution and Health(CNSCH)in schoolchildren in 2005 to evaluate the nutrition status and development level of the reference population.Results The reference population had an optimal representation of Chinese Han children and adolescents.The resulting curves provided specific cut off points based on age and sex for the diagnosis of high normal BP,hypertension and severe hypertension,respectively.Given the best approach for blood pressure measurement in children and adolescents remained controversial,especially on the choice of K4 or K5
