Yajun Liang

Secular trends in the prevalence of general and abdominal obesity among Chinese adults, 1993–2009

The objective of this study is to examine the trends in body mass index (BMI), waist circumference (WC) and prevalence of overweight (BMI 25–27.49 kg m−2), general obesity (BMI ≥ 27.5 kg m−2) and abdominal obesity (WC ≥ 90 cm for men and ≥80 cm for women) among Chinese adults from 1993 to 2009. Data were obtained from the China Health and Nutrition Survey, which was conducted from 1993 to 2009 and included a total of 52,621 Chinese adults. During the period of 1993–2009, mean BMI values increased by 1.6 kg m−2 among men and 0.8 kg m−2 among women; mean WC values increased by 7.0 cm among men and 4.7 cm among women. The prevalence of overweight increased from 8.0 to 17.1% among men (P < 0.001) and from 10.7 to 14.4% among women (P < 0.001); the prevalence of general obesity increased from 2.9 to 11.4% among men (P < 0.001) and from 5.0 to 10.1% among women (P < 0.001); the prevalence of abdominal obesity increased from 8.5 to 27.8% among men (P < 0.001) and from 27.8 to 45.9% among women (P < 0.001). Similar significant trends were observed in nearly all age groups and regions for both men and women. The prevalence of overweight, general obesity and abdominal obesity among Chinese adults has increased greatly during the past 17 years.

Trends in blood pressure and hypertension among Chinese children and adolescents: China Health and Nutrition Surveys 1991–2004

Abstract Objective. To observe the trends in blood pressure (BP) and prevalence of hypertension among Chinese children and adolescents. Methods. Data were extracted from the China Health and Nutrition Survey conducted from 1991 to 2004; 8247 children and adolescents aged 6–17 years were selected for this study. Multivariate linear regression analysis and multivariate logistic regression analysis were performed to evaluate the secular trends in BP levels and prevalence of hypertension, respectively. Results. During the study period, there was an upward trend in BP in Chinese children and adolescents. After adjustment for gender, age and weight status, the prevalence of pre-hypertension and hypertension increased dramatically from 1991 to 2004, with average relative increases of 6.38% and 8.13% in children and adolescents, respectively. Overweight was strongly associated with pre-hypertension and hypertension in comparison with normal weight, with odds ratios (95% confidence intervals) of 2.21 (1.58–3.11) and 4.13 (3.32–5.13), respectively. Conclusion. BP levels and prevalence of hypertension increased dramatically among Chinese children and adolescents from 1991 to 2004.

Trends in prevalence, awareness, treatment, and control of hypertension among Chinese adults 1991-2009

Hypertension is the main risk factor for cardiovascular disease (CVD), accounting for nearly 45% of global CVD morbidity and mortality [1]. Based on previous national survey data in China, the prevalence of hypertension in adults has increased from 5% in 1959 to 11.3% in 1991 and 18% in 2002 [2–4]. Although many studies have suggested that the control of hypertension is an effective strategy to prevent CVD [5], only a small percentage of hypertensive patients achieved the goal of systolic and diastolic blood pressure (SBP/DBP)<140/90 mm Hg. The control rate of hypertension in China was only 3% in 1991 and 5% in 2002[3,4]. Recently, three studies from China have investigated the prevalence, awareness, treatment, and control of hypertension in three urban populations [6], and two rural populations [7,8]. Recent trends in hypertension prevalence and control in China on a national level, however, are still unknown. The China Health and Nutrition Survey (CHNS) is a large-scale, national and successive cross-sectional survey that was designed to explore how the health and nutritional status of the Chinese population has been affected by social and economic changes [9]. A multistage, random cluster process was used to draw study sample from nine provinces (Liaoning, Heilongjiang, Jiangsu, Shandong, Henan, Hubei, Hunan, Guangxi and Guizhou). Participants aged 18 years and older were included in the analysis. Information on age, gender, region (the urban and rural regions were clarified according to their characteristics of economy and social development using data from the China National Bureau of Statistics and China Ministry of Health Statistics), body mass index (BMI), and BP measurements were collected. A total of 8426, 7905, 8509, 9469, 8847, 8980 and 8503 participants were included in the analyses across the seven study periods (1991, 1993, 1997, 2000, 2004, 2006, 2009). Gender distributions across the seven survey periods were homogeneous (P=0.49). BP was measured by trained examiners using a mercury sphygmomanometer according to a standard protocol [10]. The three BP values were measured on one visit, and the last two of three readings were averaged as the BP values in this study. Prevalent pre-hypertension was defined as SBP/DBP of 120/80 to 140/90 mm Hg and hypertension was defined as SBP/DBP≥140/90 mm Hg or on antihypertensive medications [10]. The same criteria were used for both diabetic and nondiabetic participants [11]. Awareness of hypertension was determined as self-reported diagnosis of hypertension by a physician or other healthcare professional. Treatment of hypertension was defined as self-report use of antihypertensive medications. Treated participants were considered to have their hypertension controlled if their SBP/DBP was less than 140/90 mm Hg. Trends in BP values and the estimated percentages (prevalence, awareness, treatment, and control of hypertension) from 1991 to 2009 were assessed with a multiple linear regression (continuous outcomes) or logistical regression (dichotomous outcomes) model [12] with the adjustment for gender, age, region, and BMI. Since age distributions in the seven study periods varied, the estimated percentages were age-standardized to the China Census population in 2000. A p value<0.05 was considered statistically significant. The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology [13]. Overall, both mean SBP and DBP values increased significantly across seven study visits (Table 1). Mean SBP values increased by 5.4 mm Hg and mean DBP increased by 4.1 mm Hg. Similar significant trends were observed in all subgroups defined by age, sex and region groups (all p 0.05). Notably, mean SBP and DBP values increased more rapidly among subjects aged 40–59 years and among those living in rural regions. Table 1 Trends in mean SBP and DBP values (mm Hg) among Chinese Adults: the CHNS 1991–2009 The prevalence of pre-hypertension and hypertension changed significantly from 29.4% and 14.5%, respectively, in 1991, to 38.7% and 21.4%, respectively, in 2009 (both p<0.001), with an absolute increase of 9.3% and 6.9% (Table 2). Similar significant trends were observed in each subgroup defined by age, sex or region (all p<0.05). The prevalence of hypertension increased more rapidly among subjects who were older than 40 years, men, and those who lived in rural regions (Table 2). Table 2 Trends in prevalence of pre-hypertension and hypertension among Chinese Adults: the CHNS 1991–2009 The awareness and treatment of hypertension decreased significantly from 22.4% and 12.0% respectively, in 1991, to 13.0% and 9.6%, respectively, in 1997 (all p 0.05) (Table 3). During the periods of 1997–2009, the awareness, treatment, and control of hypertension in all hypertensive patients and those treated increased significantly from 13.0%, 9.6%, 1.7% and 17.4% in 1997, respectively, to 26.1%, 22.8%, 6.1%, and 33.1% in 2009 (all p<0.05). In stratified analysis, during the periods of 1997–2009, the rates of awareness, treatment, and control of hypertension in all hypertensive patients and in those treated increased more rapidly in those aged 60 years or older. In addition, the rates of hypertension control in all hypertensive patients and in those treated increased more rapidly in urban regions (Table 3). Table 3 Trends in awareness, treatment, and control among Chinese hypertensive adults: the CHNS 1991–2009 To our knowledge, although three regional studies have been published [6–8], we firstly reported the recent trends in prevalence, awareness, treatment and control of hypertension among the partially representative Chinese adults from 1991 to 2009, based on the CHNS. The upward trend in mean SBP and DBP values and prevalence of hypertension was observed among Chinese adults from 1991 to 2009, which might be due to decreases in physical activity [14], increases in sedentary behavior, high fat diet, salt intake [15] and obesity [16]. In contrast, the United States National Health and Nutrition Examination Survey (NHNES) conducted for a similar period (1988–2008) showed that the prevalence of hypertension increased from 1988 to 2000, with little change between 2000 and 2008[17]. Better public health education and preventive measures from the government and health professionals might explain the increases in the awareness, treatment and control rates between 1997 and 2009. Similarly, the NHNES in the United States also demonstrated an increase in awareness, treatment and control of hypertension between 1988 and 2008[18]. Two limitations are noted. First, BP measurement at a single visit usually overestimates hypertension prevalence and underestimates control rate. Second, risk factors such as diabetes, hyperlipidemia, smoking, and family history of hypertension and data on treatment medications and prevalence of essential versus non-essential hypertension were unavailable presently. The overall prevalence of hypertension increased significantly in China between 1991 and 2009. The overall awareness, treatment, and control of hypertension (in hypertensive individuals) increased over time, but are still unacceptably low. Our results suggest an urgent need for a national hypertension education program to improve the prevention, detection, treatment, and control of hypertension in China, with the ultimate goal to lower hypertension-related morbidity and mortality.

Trends in general and abdominal obesity among Chinese children and adolescents 1993–2009

This study aimed to examine the secular trends in body mass index (BMI) and waist circumference (WC), and the prevalence of general and abdominal obesity among Chinese children and adolescents from 1993 to 2009.

Trends in incidence of hypertension in Chinese adults, 1991–2009: The China Health and Nutrition Survey

BACKGROUND/OBJECTIVES Previous studies have shown an upward trend in the prevalence of hypertension, but data on trend of incidence of hypertension are lacking. We seek to investigate the trends in incidence of hypertension and control of incident hypertension among Chinese adults during 1991-1997 and 2004-2009. METHODS Within the China Health and Nutrition Survey (1991-2009), we identified five cohorts of adults (age ≥ 18 years) who were free of hypertension at baseline of each cohort: cohorts 1991-1997 (n=4107), 1993-2000 (n=4068), 1997-2004 (n=4141), 2000-2006 (n=4695), and 2004-2009 (n=4523). Data on demographics, smoking, alcohol intake, physical activity, body mass index (BMI), and blood pressure were collected through interviews and clinical examination. Hypertension was defined as blood pressure ≥ 140/90 mmHg or currently using antihypertensive drugs. Multiple generalized estimation equations and Coxregression models were used to test the trends in blood pressure, incidence of hypertension, use of antihypertensive drugs, and control status of incident hypertension. RESULTS After controlling for potential confounders, incidence of hypertension (per 100 person-years) significantly increased from 2.9 in 1991-1997 to 5.3 in 2004-2009 (ptrend=0.024); the linear trend was statistically or marginally significant in the age group of 18-39 years, in women, in rural residents, and in adults with normal BMI. The overall rates of antihypertensive treatment and control of incident hypertension increased significantly from 5.7% and 1.7% in 1991-1997 to 19.9% and 7.6% in 2004-2009, respectively (ptrend<0.001). CONCLUSIONS The incidence of hypertension has increased in Chinese adults since early 1990s. The treatment and control status of incident hypertension, while improved, remain very poor.

Increase in Body Mass Index, Waist Circumference and Waist-to-Height Ratio is Associated with High Blood Pressure in Children and Adolescents in China:

This study compared the association between blood pressure (BP) and obesity in 1145 Chinese children and adolescents (608 males, 537 females) using data from the 2006 China Health and Nutrition Survey. Obesity was diagnosed by body mass index (BMI), waist circumference (WC) and waist-to-height ratio (WHtR). Analysis of variance was used to analyse the difference in BP among different subgroups. Odds ratios (OR) were calculated and multivariate logistic regression analysis was carried out. The prevalence of high systolic and diastolic BP increased directly with corresponding increments in BMI, WC and WHtR, although the prevalence and OR of high BP were higher when increased BMI was combined with WC (OR 3.39; 95% confidence interval [CI] 1.79, 6.41) or WHtR (OR 3.28; 95% CI 1.71, 6.30). In conclusion, increased BMI, WC and WHtR were directly associated with high BP in Chinese children and adolescents.

Hypertension trends in Chinese children in the national surveys, 1993 to 2009

Hypertension, the risk factor for cardiovascular disease, is a major cause of adult morbidity and mortality worldwide [1]. Epidemiological studies have indicated that adult hypertension begins at childhood [2]. Actually, hypertension at childhood is significantly associated with increased risk of end-organ damage Table 3 Factors associated with recurrent atrial fibrillation in patients randomized to rhythm control.

Hypertension Screening Using Blood Pressure to Height Ratio

OBJECTIVES: The definition of hypertension in children is too complex to be used by medical professionals and children and their parents because of the age-, gender-, and height-specific blood pressure (BP) algorithm. The aim of this study was to simplify the pediatric BP percentile references using BP to height ratio (BPHR, equal to BP/height) for screening for prehypertension and hypertension in Chinese children. METHODS: Data were obtained from the China Health and Nutrition Survey, which was conducted from 1991 to 2009 and included 11 661 children aged 6 to 17 years with complete data on age, gender, height, and BP values. Receiver operating characteristic curve analysis was performed to assess the performance of systolic BPHR (SBPHR) and diastolic BPHR (DBPHR) for screening for pediatric prehypertension and hypertension. RESULTS: The optimal thresholds for defining prehypertension were 0.81 in children aged 6 to 11 years and 0.70 in adolescents aged 12 to 17 years for SBPHR and 0.52 in children and 0.46 in adolescents for DBPHR, respectively. The corresponding values for hypertension were 0.84, 0.78, 0.55, and 0.50, respectively. The negative predictive values were much higher (all ≥99%) for prehypertension and hypertension, although the positive predictive values were relatively lower, ranging from 13% to 75%. CONCLUSIONS: BPHR index is simple and accurate for screening for prehypertension and hypertension in Chinese children aged 6 to 17 years and can be used for early screening or treating Chinese children with hypertension.

Cardiovascular risk factor profiles for peripheral artery disease and carotid atherosclerosis among Chinese older people: a population-based study.

Objectives Epidemiological data concerning atherosclerotic disease among older people in rural China are sparse. We seek to determine prevalence and cardiovascular risk factor profiles for peripheral artery disease (PAD) and carotid atherosclerosis (CAS) among Chinese older people living in a rural community. Methods This cross-sectional study included 1499 participants (age ≥60 years, 59.0% women) of the Confucius Hometown Aging Project in Shandong, China. From June 2010–July 2011, data were collected through interviews, clinical examinations, and laboratory tests. PAD was defined as an ankle-brachial index ≤0.9. Carotid intima-media thickness (cIMT) and carotid artery stenosis were assessed by ultrasonography. We defined moderate stenosis as carotid stenosis ≥50%, and severe stenosis as carotid stenosis ≥70%. cIMT≥1.81 mm was considered as an increased cIMT (a measure of CAS). Data were analyzed with multiple logistic models. Results The prevalence was 5.7% for PAD, 8.9% for moderate stenosis, 1.8% for severe stenosis, and 11.2% for increased cIMT. After controlling for multiple potential confounders, diabetes, an increased low-density lipoprotein cholesterol (LDL-C)/high-density lipoprotein cholesterol (HDL-C) ratio, and hypertension were significantly or marginally associated with PAD. Ever smoking, hypertension, and an increased LDL-C/HDL-C ratio were significantly associated with an increased likelihood of increased cIMT. An increasing number of those cardiovascular risk factors were significantly associated with an increasing odds ratio of PAD and increased cIMT, respectively (p for linear trend <0.001). Conclusion Among Chinese older people living in a rural community, PAD, carotid artery stenosis, and an increased cIMT are relatively uncommon. Cardiovascular risk factor profiles for PAD and CAS are slightly different, with hypertension and an increased LDL-C/HDL-C ratio being associated with an increased likelihood of both PAD and increased cIMT.

Prevalence and risk factors of hypertension based on repeated measurements in Chinese children and adolescents

Abstract Objectives: This study aimed to determine the prevalence of hypertension from repeated blood pressure (BP) measurements, and examine the association between hypertension and obesity, as well as other related risk factors, in a Chinese pediatric population. Methods: A total of 6692 children, aged 3–18 years, were recruited in 2010. Anthropometric measurements and BP were measured using a mercury sphygmomanometer. Those with an elevated BP were screened a second or third time at 2-week intervals. “Hypertension” was defined as elevated BP on all three occasions. A self-administered questionnaire was completed. Results: The prevalence of an elevated BP was 18.2%, 5.1% and 3.1% on the first, second and third visits, respectively. The odds ratios (ORs) and 95% confidence intervals (CIs) for an elevated BP among obese children were 7.07 (5.94–8.42), 17.23 (12.63–23.52) and 20.63 (13.69–31.09), and among those with a paternal history of hypertension were 1.26 (0.98–1.61), 1.35 (0.90–2.02) and 1.80 (1.15–2.81) on each consecutive visit. Conclusions: Repeated measurements are required to confirm the diagnosis of hypertension in children and that obesity and paternal hypertension are strongly associated with pediatric hypertension.