Bo Xi

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.

Prevalence of metabolic syndrome and its influencing factors among the Chinese adults: The China Health and Nutrition Survey in 2009

OBJECTIVE We aimed to estimate the up-to-date prevalence of metabolic syndrome (MS) and its influencing factors among the Chinese adults. METHODS Data were obtained from the China Health and Nutrition Survey conducted in 2009, which was a cross-sectional and partially nationally representative study including a total of 7488 Chinese adults (age ≥18 years). RESULTS The overall age-standardized prevalence estimates of the MS were 21.3% (95%confidence interval (CI): 20.4%-22.2%), 18.2% (95%CI: 17.3%-19.1%) and 10.5% (95%CI: 9.8%-11.2%) based on definitions of revised NCEP ATPIII, IDF and CDS criteria, respectively. Individuals who were women (compared to men: odds ratio [OR]=1.37, 95% CI=1.16-1.61), 40 years or older (compared to less than 40 years old: OR=2.82, 95%CI=2.37-3.34 for 40-59 years; OR=4.41, 95%CI=3.68-5.29 for 60 years or older), overweight/obese (compared to normal weight: OR=4.32, 95%CI=3.77-4.95 for overweight; OR=11.24, 95%CI=9.53-13.26 for obese), and living in urban area (compared to living in rural area: OR=1.27, 95%CI=1.12-1.43) were more likely to have a higher prevalence estimate of MS. In addition, frequency of alcohol consumption and cigarette intake were also found to be significantly associated with probability of MS. CONCLUSIONS Our results suggest an urgent need to develop national strategies for the prevention, detection, treatment and control of obesity and MS in China.

Short sleep duration is associated with hypertension risk among adults: a systematic review and meta-analysis.

A number of studies have reported that sleep duration might have an important role in the development of hypertension. However, the results have been inconsistent. In this study, a meta-analysis was performed to clarify the association between sleep duration and hypertension risk. PubMed, Embase and ISI web of science databases updated on 28 October 2011 were searched for eligible publications. Pooled odds ratio (OR) or relative risk (RR) with 95% confidence intervals (CI) was calculated using a random- or fixed-effect model. Six prospective (N=9959) and seventeen cross-sectional (N=105432) studies were identified for the data analysis on sleep duration. The results indicated that short sleep duration was associated with an increased risk of prevalent hypertension (OR=1.20, 95% CI: 1.09–1.32, P<0.001), especially among subjects younger than 65 years and females. In addition, short sleep duration was also associated with an increased risk of incident hypertension among subjects younger than 65 years (RR=1.33, 95% CI: 1.11–1.61, P=0.002). Overall, there was a significant association between long sleep duration and the risk of prevalent hypertension (OR=1.11, 95% CI: 1.05–1.17, P<0.001). Further subgroup analysis also suggested a significant association between long sleep duration and the risk of prevalent hypertension among subjects younger than 65 years (OR=1.12, 95% CI: 1.06–1.19, P<0.001). The present meta-analysis indicated that short sleep duration was associated with an increased risk of hypertension in the overall polulation and incident hypertension among subjects younger than 65 years. In addition, long sleep duration might be associated with a risk of prevalent hypertension, especially among subjects younger than 65 years.

Physical Activity and Risk of Hypertension A Meta-Analysis of Prospective Cohort Studies

Published literature reports controversial results about the association of physical activity (PA) with risk of hypertension. A meta-analysis of prospective cohort studies was performed to investigate the effect of PA on hypertension risk. PubMed and Embase databases were searched to identify all related prospective cohort studies. The Q test and I 2 statistic were used to examine between-study heterogeneity. Fixed or random effects models were selected based on study heterogeneity. A funnel plot and modified Egger linear regression test were used to estimate publication bias. Thirteen prospective cohort studies were identified, including 136 846 persons who were initially free of hypertension, and 15 607 persons developed hypertension during follow-up. The pooled relative risk (RR) of main results from these studies suggests that both high and moderate levels of recreational PA were associated with decreased risk of hypertension (high versus low: RR, 0.81; 95% confidence interval, 0.76–0.85 and moderate versus low: RR, 0.89; 95% confidence interval, 0.85–0.94). The association of high or moderate occupational PA with decreased hypertension risk was not significant (high versus low: RR, 0.93; 95% confidence interval, 0.81–1.08 and moderate versus low: RR, 0.96; 95% confidence interval, 0.87–1.06). No publication bias was observed. The results of this meta-analysis suggested that there was an inverse dose–response association between levels of recreational PA and risk of hypertension, whereas there was no significant association between occupational PA and hypertension. # Novelty and Significance {#article-title-46}Published literature reports controversial results about the association of physical activity (PA) with risk of hypertension. A meta-analysis of prospective cohort studies was performed to investigate the effect of PA on hypertension risk. PubMed and Embase databases were searched to identify all related prospective cohort studies. The Q test and I2 statistic were used to examine between-study heterogeneity. Fixed or random effects models were selected based on study heterogeneity. A funnel plot and modified Egger linear regression test were used to estimate publication bias. Thirteen prospective cohort studies were identified, including 136 846 persons who were initially free of hypertension, and 15 607 persons developed hypertension during follow-up. The pooled relative risk (RR) of main results from these studies suggests that both high and moderate levels of recreational PA were associated with decreased risk of hypertension (high versus low: RR, 0.81; 95% confidence interval, 0.76–0.85 and moderate versus low: RR, 0.89; 95% confidence interval, 0.85–0.94). The association of high or moderate occupational PA with decreased hypertension risk was not significant (high versus low: RR, 0.93; 95% confidence interval, 0.81–1.08 and moderate versus low: RR, 0.96; 95% confidence interval, 0.87–1.06). No publication bias was observed. The results of this meta-analysis suggested that there was an inverse dose–response association between levels of recreational PA and risk of hypertension, whereas there was no significant association between occupational PA and hypertension.

Short sleep duration predicts risk of metabolic syndrome: A systematic review and meta-analysis

Sleep duration has been suggested to play a key role in the development of metabolic syndrome (MS). However, the results have been inconsistent. The objective of this study was to clarify the association between sleep duration and MS risk. PubMed and Embase databases were searched for eligible publications. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated using random- or fixed-model. A total of 12 studies (18,720 MS cases and 70,833 controls) were included in the meta-analysis. Short sleep duration was significantly associated with increased risk of MS (OR = 1.27, 95%CI = 1.09-1.47, p = 0.002). Long sleep duration was not associated with increased risk of MS (OR = 1.07, 95%CI = 0.87-1.32, p = 0.535). Similar results were found in both men and women. The sensitivity analysis confirmed the stability of the results and no publication bias was detected. The present meta-analysis suggests that short rather than long sleep duration is significantly associated with risk of MS. Large-scale well-design prospective studies are required to further investigate the association between sleep duration and MS risk.

The common rs9939609 variant of the fat mass and obesity-associated gene is associated with obesity risk in children and adolescents of Beijing, China

BackgroundPrevious genome-wide association studies for type 2 diabetes susceptibility genes have confirmed that a common variant, rs9939609, in the fat mass and obesity associated (FTO) gene region is associated with body mass index (BMI) in European children and adults. A significant association of the same risk allele has been described in Asian adult populations, but the results are conflicting. In addition, no replication studies have been conducted in children and adolescents of Asian ancestry.MethodsA population-based survey was carried out among 3503 children and adolescents (6-18 years of age) in Beijing, China, including 1229 obese and 2274 non-obese subjects. We investigated the association of rs9939609 with BMI and the risk of obesity. In addition, we tested the association of rs9939609 with weight, height, waist circumference, waist-to-height ratio, fat mass percentage, birth weight, blood pressure and related metabolic traits.ResultsWe found significant associations of rs9939609 variant with weight, BMI, BMI standard deviation score (BMI-SDS), waist circumference, waist-to-height ratio, and fat mass percentage in children and adolescents (p for trend = 3.29 × 10-5, 1.39 × 10-6, 3.76 × 10-6, 2.26 × 10-5, 1.94 × 10-5, and 9.75 × 10-5, respectively). No significant associations were detected with height, birth weight, systolic and diastolic blood pressure and related metabolic traits such as total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol and fasting plasma glucose (all p > 0.05). Each additional copy of the rs9939609 A allele was associated with a BMI increase of 0.79 [95% Confidence interval (CI) 0.47 to 1.10] kg/m2, equivalent to 0.25 (95%CI 0.14 to 0.35) BMI-SDS units. This rs9939609 variant is significantly associated with the risk of obesity under an additive model [Odds ratio (OR) = 1.29, 95% CI 1.11 to 1.50] after adjusting for age and gender. Moreover, an interaction between the FTO rs9939609 genotype and physical activity (p < 0.001) was detected on BMI levels, the effect of rs9939609-A allele on BMI being (0.95 ± 0.10), (0.77 ± 0.08) and (0.67 ± 0.05) kg/m2, for subjects who performed low, moderate and severe intensity physical activity.ConclusionThe FTO rs9939609 variant is strongly associated with BMI and the risk of obesity in a population of children and adolescents in Beijing, China.

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.

Associations of Six Single Nucleotide Polymorphisms in Obesity-Related Genes With BMI and Risk of Obesity in Chinese Children

OBJECTIVE Childhood obesity strongly predisposes to some adult diseases. Recently, genome-wide association (GWA) studies in Caucasians identified multiple single nucleotide polymorphisms (SNPs) associated with BMI and obesity. The associations of those SNPs with BMI and obesity among other ethnicities are not fully described, especially in children. Among those previously identified SNPs, we selected six (rs7138803, rs1805081, rs6499640, rs17782313, rs6265, and rs10938397, in or near obesity-related genes FAIM2, NPC1, FTO, MC4R, BDNF, and GNPDA2, respectively) because of the relatively high minor allele frequencies in Chinese individuals and tested the associations of the SNPs with BMI and obesity in Chinese children. RESEARCH DESIGN AND METHODS We investigated the associations of these SNPs with BMI and obesity in school-aged children. A total of 3,503 children participated in the study, including 1,229 obese, 655 overweight, and 1,619 normal-weight children (diagnosed by the Chinese age- and sex-specific BMI cutoffs). RESULTS After age and sex adjustment and correction for multiple testing, the SNPs rs17782313, rs6265, and rs10938397 were associated with BMI (P = 1.0 × 10−5, 0.038, and 0.00093, respectively) and also obesity (P = 5.0 × 10−6, 0.043, and 0.00085, respectively) in the Chinese children. The SNPs rs17782313 and rs10938397 were also significantly associated with waist circumference, waist-to-height ratio, and fat mass percentage. CONCLUSIONS Results of this study support obesity-related genes in adults as important genes for BMI variation in children and suggest that some SNPs identified by GWA studies in Caucasians also confer risk for obesity in Chinese children.

Nut consumption in relation to cardiovascular disease risk and type 2 diabetes: a systematic review and meta-analysis of prospective studies

BACKGROUND Many prospective cohort studies have investigated the association between nut consumption and risk of coronary artery disease (CAD), stroke, hypertension, and type 2 diabetes (T2D). However, results have been inconsistent. OBJECTIVE We aimed to investigate the association between nut consumption and risk of CAD, stroke, hypertension, and T2D. DESIGN PubMed and EMBASE databases were searched up to October 2013. All prospective cohort studies of nut consumption and risk of CAD, stroke, hypertension, and T2D were included. Summary RRs with 95% CIs were estimated by using a fixed- or random-effects model. RESULTS A total of 23 prospective studies (9 studies for CAD, 4 studies for stroke, 4 studies for hypertension, and 6 studies for T2D) from 19 publications were included in the meta-analysis. There were 179,885 participants and 7236 CAD cases, 182,730 participants and 5669 stroke cases, 40,102 participants and 12,814 hypertension cases, and 342,213 participants and 14,400 T2D cases. The consumption of each 1 serving of nuts/d was significantly associated with incident CAD (RR: 0.81; 95% CI: 0.72, 0.91; P < 0.001) and hypertension (RR: 0.66; 95% CI: 0.44, 1.00; P = 0.049). However, there was no association between the consumption of each 1 serving of nuts/d and risk of stroke (RR: 0.90; 95% CI: 0.71, 1.14) or T2D (RR: 0.80; 95% CI: 0.57, 1.14). CONCLUSIONS A higher consumption of nuts was associated with reduced risk of CAD and hypertension but not stroke or T2D. Large randomized controlled trials are warranted to confirm the observed associations.

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.