| BackgroundHypertension has already become an important issue of public health. The prevalence of hypertension in adults has been increasing globally from 26.4%in 2000 to the total estimated prevalence of 29.2%in 2025. Meanwhile, the hypertensive patients are becoming younger. However, levels of blood pressure (BP) are difficult to be efficiently controlled in nearly 70%of hypertensive patients. It is the worldwide serious challenge to increase the control rate of hypertension. The target organ damages of heart, brain, kidney, and artery are the important problems of hypertension study. The identification of target organ damage (TOD) is significantly important to evaluate the cardiovascular risk of hypertensive patients.With the prevalence of childhood obesity increasing, primary hypertension has become the common disease among children and adolescents. The prevalence of hypertension in childhood is increasing year by year. BP tracks from childhood to adulthood, and the onset of primary hypertension is proved to be traced back to childhood. Childhood hypertension is closely correlated with adulthood hypertension. Childhood hypertension not only causes the high risks of adult hypertension, but also does damage to target organs of artery, heart, brain and kidney. The signs of TOD have been found in large proportions of hypertensive children. However, BP tracking changes with the growth of children, especially under the changes of physiology and hormone during puberty. It is still an unsolved problem about the predictive risk of adult hypertension and TOD based on childhood hypertension and different ages of hypertension onset.Objectives1. To observe the changes of BP levels and status from childhood to adulthood, and describe the phenomenon of BP tracking.2. To analyze the predictive risks of hypertension and TOD in adulthood based on hypertension and different ages of hypertension onset in childhood.3. To observe the predictive risks of adult TOD based on the crossover effect of hypertension in childhood and adulthood.MethodsAll study participants came from whole population of 3198 subjects (1700 males, 53.2%) from the national project of The 7th Five Year Plan, named "Beijing Children and Adolescents BP Study (BBS)". Prospective cohort study was conducted to follow up this population in this study. Up to now, a total of 1126 subjects (631 males,56.0%) from the BBS cohort have been followed up and invited to participate in the clinical examination in 2010, with the proportion of 35.2%. Now the follow up study on BBS cohort is still going. In this study, we collected and analyzed the data of 1126 subjects to observe the BP tracking and the predictive risks of adult hypertension and TOD based on hypertension in childhood. Data of demography, disease history, family history of hypertension, life style were collected through questionnaire. Their anthropometric indexes including height (cm), weight (kg), systolic BP (SBP, mmHg), diastolic BP (DBP, mmHg) were measured through unified and standardized methods, with body mass index (BMI) being calculated as weight in kilograms divided by the square of height in meters, kg/m2) at baseline and follow up surveys. Moreover, other indexes such as heart rate (beats/min), pulse wave velocity (PWV, cm/s), structure of left ventricular, micro albumin in urine (mg/L), blood glucose (mmol/L), and blood lipid (mmol/L) were also measured at follow up study.Overweight and obesity in children and adolescents (7-18 years old) were defined according to the age-and gender-specific BMI reference values proposed by the Working Group on Obesity in China. We used the age-and gender-specific 85th and 95th BMI percentile from the Growth Charts proposed by US Center for Disease Control and Prevention in 2000 to define overweight and obesity in children aged 6 years old, respectively. In adults, overweight was defined as BMI≥24 kg/m2 and BMI<28 kg/m2, and obesity was defined as BMI≥28 kg/m2. Among children and adolescents, Krotkoff sound phase 1 and phase 4 were defined as SBP and DBP, respectively. We used the age-and gender-specific BP reference standard of Chinese children and adolescents to define pre-hypertension and hypertension. Both SBP and DBP<90th percentile was defined as normal BP; SBP and/or DBP≥90th percentile and<95th percentile was defined as high normal; SBP and/or DBP≥95th percentile was defined as hypertension. In adulthood, hypertension was diagnosed according to the China Guideline for Hypertension Prevention and Control issued in 2009. Adult hypertension was diagnosed as SBP≥140 mm Hg and/or DBP≥90 mm Hg or the subjects who were taking anti-hypertension drugs presently. Artery stiffness was defined as brachial-ankle PWV (baPWV)≥1400 cm/s; aorta stiffness was defined as carotid-femoral PWV (cfPWV)≥900 cm/s. Left ventricular hypertrophy (LVH) was defined as left ventricular mass index (LVMI)>51 g/m2.7 or relative wall thickness (RWT)>0.41. Microalbuminuria (MAU) was defined as the concentration of micro albumin≥30 mg/L in urine. Diabetes was diagnosed according to the criteria recommended by American Diabetes Association in 2006. Dyslipidemia was diagnosed according to the China's Guideline on Prevention and Treatment of Adult Dyslipidemia in 2007.Data of investigation and examination at baseline and follow up surveys were combined together, and SPSS 13.0 software was used to analyze data. Data of non-normal distribution were turned into normal distribution through natural logarithm transformation before being analyzed. The methods of analyses included student t test, chi-square test, covariance analysis, multivariable linear regression, and multivariate logistic regression. After adjustment of possible confounding factors, we observed the predictive risks of adult hypertension and TOD based on hypertension and ages of hypertension onset in childhood.Results1. After adjustment of age, BMI in childhood and adulthood, BP in adulthood increased with the BP increasing in childhood among boys and girls of all ages (P<0.05). Children with high percentile of BP levels were observed to have higher BP levels and prevalence of hypertension in adulthood. With the increases in BP percentile in childhood, BP levels and prevalence of hypertension in adulthood increased accordingly. The prevalence of adult hypertension was 5.0%in children with BPP95. After adjustment of age, gender, childhood obesity, adulthood obesity, family history of hypertension, smoking, drinking and physical activity, with the increase of BP in childhood, the risks of adult hypertension increased gradually, with odds ratio (OR) from 1.94 (P=0.311) in BP |
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