Prevalence, awareness, treatment, and control of hypertension among herdsmen living at 4,300 m in Tibet

Hypertension status and its risk factors in highlanders living in Ganzi Tibetan Plateau: a cross-sectional study

BACKGROUND

The updated status of hypertension and its risk factors are poorly evaluated in Tibetan highland areas. We initiated a large-scale cross-sectional survey to provide updated status of hypertension and its risk factors (especially salt intake) in the Ganzi Tibetan Plateau, China.

METHODS

Stratified multistage random sampling was performed to obtain a representative sample of 4,036 adult residents from 4 counties in the Ganzi Tibetan area. The whole survey population was used to present the epidemiology and risk factors of hypertension. The participants with blood and urine biochemistry data were used to analyze the relationship between salt intake parameters and hypertension.

RESULTS

Stratified multistage random sampling was performed to obtain a representative sample of 4,036 adult residents. The overall prevalence rate of hypertension was 33.5% (the age-adjusted prevalence rate was 28.9%). A total of 50.9% of the hypertensive patients knew their conditions; 30.1% of them received antihypertensive treatment; and 11.2% of them had their blood pressure controlled. Age, male sex, living altitude ≥ 3500 m, overweight and abdominal obesity were positively correlated with hypertension. In addition, the adjusted odds ratio (OR) for hypertension was 1.33 (95% CI: 1.01-1.74) for drinking tea with salt, and 1.51 (95% CI: 1.32-1.72) for per SD increase in the estimation of 24-hour urinary sodium excretion (e24hUSE). Furthermore, per 100mmol/day increase in e24hUSE was associated with elevation of blood pressure (+ 10.16, 95% CI: 8.45-11.87 mmHg for SBP; +3.83, 95% CI: 2.74-4.93 mmHg for DBP) in this population.

CONCLUSIONS

Our survey suggests a heavy disease burden of hypertension in the Ganzi Tibetan Plateau. Age, male sex, altitude of residence ≥ 3500 m, overweight, abdominal obesity, and excessive salt intake (shown as drinking tea with adding salt and a higher level of e24hUSE) all increased the risk of hypertension in this highland area.

New strategy for rational use of antihypertensive drugs in clinical practice in high-altitude hypoxic environments

High-altitude hypoxic environments have critical implications on cardiovascular system function as well as blood pressure regulation. Such environments place patients with hypertension at risk by activating the sympathetic nervous system, which leads to an increase in blood pressure. In addition, the high-altitude hypoxic environment alters the in vivo metabolism and antihypertensive effects of antihypertensive drugs, which changes the activity and expression of drug-metabolizing enzymes and drug transporters. The present study reviewed the pharmacodynamics and pharmacokinetics of antihypertensive drugs and its effects on patients with hypertension in a high-altitude hypoxic environment. It also proposes a new strategy for the rational use of antihypertensive drugs in clinical practice in high-altitude hypoxic environments. The increase in blood pressure on exposure to a high-altitude hypoxic environment was mainly dependent on increased sympathetic nervous system activity. Blood pressure also increased proportionally to altitude, whilst ambulatory blood pressure increased more than conventional blood pressure, especially at night. High-altitude hypoxia can reduce the activities and expression of drug-metabolizing enzymes, such as CYP1A1, CYP1A2, CYP3A1, and CYP2E1, while increasing those of CYP2D1, CYP2D6, and CYP3A6. Drug transporter changes were related to tissue type, hypoxic degree, and hypoxic exposure time. Furthermore, the effects of high-altitude hypoxia on drug-metabolism enzymes and transporters altered drug pharmacokinetics, causing changes in pharmacodynamic responses. These findings suggest that high-altitude hypoxic environments affect the blood pressure, pharmacokinetics, and pharmacodynamics of antihypertensive drugs. The optimal hypertension treatment plan and safe and effective medication strategy should be formulated considering high-altitude hypoxic environments.

Prevalence of hypertension in adults living at altitude in Latin America and the Caribbean: A systematic review and meta-analysis

OBJECTIVE

The objective of this systematic review and meta-analysis was to assess the prevalence of hypertension in populations living at altitude in Latin America and the Caribbean.

METHODS

We conducted a systematic search from January 1, 2000 to January 10, 2023 in Web of Science (WoS)/Core Collection, WoS/Medline, WoS/Scielo, Scopus, PubMed and Embase databases. We included studies that assessed the prevalence of hypertension in altitude populations (>1500 m.a.s.l.) and these were meta-analyzed using a random-effects model. To assess the sources of heterogeneity, we performed subgroup and meta-regression analyses.

RESULTS

Thirty cross-sectional studies (117 406 participants) met the inclusion criteria. Studies used different cut-off points. The prevalence of hypertension in the studies that considered the cut-off point of ≥ 140/90 mmHg in the general population was 19.1%, ≥ 130/85 mmHg was 13.1%, and ≥ 130/80 mmHg was 43.4%. There was a tendency for the prevalence of hypertension to be higher in men. In meta-regression analyses, no association was found between altitude, mean age, year of publication, risk of bias and prevalence of hypertension.

CONCLUSION

The prevalence of hypertension in the altitude population of Latin America and the Caribbean is lower than that reported in populations living at sea level and lower than other altitude populations such as Tibetans.

PROSPERO

CRD42021275229.

Structural and functional dysbiosis of gut microbiota in Tibetan subjects with coronary heart disease

The gut microbiota plays a crucial role in coronary heart disease (CHD). However, only a few studies focusing on the relationship between gut microbiota and CHD in ethnic populations are available. Here, we employed shotgun sequencing of the gut metagenome to analyze the taxonomic composition and functional annotation of the gut microbiota of 14 CHD patients, 13 patients with non-stenosis coronary heart disease (NCHD), and 18 healthy controls (HT) in Tibetan subjects. We found that the α-diversity of the gut microbiota was not significantly different among the three groups., whereas β-diversity was significantly altered in the CHD group compared with HT. Based on the receiver operating characteristic curve (ROC) analysis, the relative abundance of Proteobacteria species effectively distinguished patients with CHD from the control group. Most of the enriched species belonged to Proteobacteria. The pathways that contributed the most to the differences between groups were amino acid metabolism-related pathways, especially lysine biosynthesis. The enzymes of the lysine biosynthesis pathway, including K01714 and K00821, were significantly decreased in the CHD group. Our findings increase the understanding of the association between CHD pathogenesis and gut microbiota in the Tibetan population, thus paving the way for the development of improved diagnostic methods and treatments for Tibetan patients with CHD.

Rate and risk factors of metabolic components and component combinations according to hypertension status in Tibetans in a cross-sectional study

To estimate the prevalence of metabolic syndrome (MS) and metabolic components and their associated factors and component combinations according to hypertension status in Tibetans living at high altitude. Multistage sampling of 1473 participants (799 hypertensive patients and 674 normotensive subjects). MS prevalence and the number of metabolic components ≥ 3 were significantly higher in the hypertensive than normotensives. In hypertensive patients, the most common component was central obesity and it combined with: high blood pressure, in those with 2 risk factors, plus fasting hyperglycemia, in those with 3 risk factors, and high triglyceride, in those with 4 risk factors. In normotensive subjects, the most common single component was low high-density-lipoprotein cholesterol, and most component combination included central obesity and hyperglycemia in those with 2 risk factors, plus high blood pressure in those with 3 risk factors, and high triglycerides in those with 4 risk factors. Body mass index and female both were associated with increased possibilities of MS in hypertensive and normotensive participants. Low incoming, and high educational levels were associated with an elevated probability of MS in normotensive Tibetans also. The priority of prevention from cardiovascular diseases by targeting metabolic components in the hypertensive was different from normotensives. Different MS components had various lifestyle and socioeconomic factors.

Anthropometric indices, body function, and physical fitness reference values for Tibetan ethnic children aged 6-17 residing at 3,650 meters above sea level

Objectives

It is known that high altitude influences the growth metrics of high-altitude residents. Using a WHO-recommended standard, the research aimed to establish growth and development reference values for children of Tibetan ethnicity between the ages of 6 and 17 years old.

Methods

The measurements took place in Jomda County, Tibet with an average altitude of 3,650 m above sea level. A total of 3,955 observations (1,932 boys and 2,023 girls) were utilized to model the centile estimations. Included in the measurements are height, weight, body mass index, heart rate, blood pressure, forced lung capacity, sit and reach, and standing long jump. The measurements were modeled using the generalized additive models for location, scale, and shape (GAMLSS). Models were fitted with suitable distributions and locally smoothed using the P-spline for each GAMLSS hyper-parameter. Using the smallest Schwarz Bayesian criterion, the optimal model for each measurement was selected. After model adjustment, centile estimations were calculated for each model.

Results

Compared to the height reference values at the 50th percentile for multi-ethnic Chinese children residing at low altitudes, Tibetan ethnic children exhibit apparent stunted growth. In terms of forced vital capacity, it is remarkable that Tibetan ethnic children lag behind multi-ethnic Chinese children residing at low altitudes. Heart rate and blood pressure regulation are generally normal. Centile estimations are provided in this article and tabulated centiles (1p, 3p, 5p, 15p, 25p, 50p, 75p, 85p, 95p, 97p, 99p) in Chinese, Tibetic, and English are openly available in FigShare (doi: 10.6084/m9.figshare.20898196.v1).

Conclusion

This study established the first GAMLSS based growth and development reference values for Tibetan ethnic children aged 6–17. These reference values have numerous clinical and scientific applications. We offer Chinese policymakers with practical initiatives to further enhance the health of Tibetan ethnic children.

Prevalence of hypertension and its relationship with altitude in highland areas: a systematic review and meta-analysis

This systematic review and meta-analysis synthesized the pooled prevalence of hypertension at high altitudes and explored its correlation with altitude using studies published in Chinese and English from database inception to February 2021. A systematic literature search was conducted among bibliographic databases (PubMed, Embase, and Web of Science) and three Chinese databases (CNKI, VIP, and Wanfang data) to identify eligible studies. A random-effects model was used to calculate the overall pooled prevalence of hypertension. The I² statistic was used to assess heterogeneity across studies. Random-effects meta-regression was conducted to investigate covariates that may have influenced between-study heterogeneity. The pooled prevalence of hypertension among the general population in high-altitude areas was 33.0% (95% CI: 29.0-38.0%), with high between-study heterogeneity (I² = 99.4%, P < 0.01). Subgroup analyses showed the pooled prevalence of hypertension in Tibetan individuals was significantly higher than that in non-Tibetan individuals living in the Himalayas and Pamir Mountains (41% vs. 18%). A trend toward an increase in the prevalence of hypertension was found with every 100-m increase in elevation (coefficient: 0.012, 95% CI: -0.001 to 0.025, P = 0.069) only in Tibetan individuals. In addition, in these individuals, we found an increase in mean diastolic BP with each 100-m increase in altitude (coefficient: 0.763, 95% CI: 0.122-1.403, P = 0.025). Our meta-analysis suggests that the pooled prevalence of hypertension among the general population in high-altitude areas is 33.0%. Subjects of Tibetan ethnicity were more prone to developing hypertension at high altitudes. However, a very weak relationship between altitude and the prevalence of hypertension was found only in Tibetan individuals.

The Characteristics of Sleep Apnea in Tibetans and Han Long-Term High Altitude Residents

PURPOSE

Obstructive sleep apnea (OSA) is common both at low and high altitude. Since adaptations to high altitude and respiratory control may differ among Tibetans and Hans, we compared characteristics of sleep-disordered breathing in the two ethnic groups at high altitude.

MATERIALS AND METHODS

This was a prospective observational study including 86 Tibetan and Han long-term (>5 years) high altitude residents with chief complaints of snoring and/or witnessed apnea underwent clinical evaluation and polysomnography at 3200 meters in Shangri-La, China.

RESULTS

In 42 Tibetans, 38 men, median (quartiles) age was 50.0 (41.0; 56.0)y, total apnea/hypopnea index (AHI) 53.9 (32.0; 77.5)/h, obstructive AHI 51.0 (28.0; 72.2)/h and central AHI 1.5 (0.2; 3.1)/h. In 44 Hans, 32 men, median (quartiles) age was 47.0 (43.5; 51.0)y, total AHI 22.2 (12.8; 39.2)/h, obstructive AHI 17.7 (12.0; 33.0)/h and central AHI 2.4 (0.5; 3.4)/h (p < 0.001 total and obstructive AHI vs Tibetans). In Tibetans, mean nocturnal oxygen saturation was lower [median 85.0 (83.0; 88.0)% vs 88.5 (87.0; 90.0)%] and obstructive apnea and hypopnea duration was longer [22.0 (19.6; 24.8) sec vs 18.3 (16.7; 20.6) sec] than in Hans (all p < 0.001). In regression analysis, Tibetan ethnicity, neck circumference and high-altitude living duration were the predictors of total AHI. We also found that with every 10/h increase in total AHI, there were an approximately 0.9 beat/min and 0.8 beat/min increase in mean heart rate during rapid eye movement (REM) and non-REM sleep and 1.9 mmHg and 2.0 mmHg increase in evening and morning systolic blood pressure.

CONCLUSION

Our data suggest that Tibetans presented more severe obstructive sleep apnea, hypoxemia and longer apnea duration compared to Hans at 3200 meters, which was correlated with higher heart rate and blood pressure suggesting a greater cardiovascular risk.

Prevalence, awareness, treatment and control of hypertension among Ngawa Tibetans in China: a cross-sectional study

OBJECTIVES

To explore the prevalence, awareness, treatment and control rate of hypertension and analyse the potential social environment factors among Ngawa Tibetans in China.

DESIGN

This was a cross-sectional observational study.

SETTING

The investigation based on a multistage stratified cluster sampling was conducted in the Ngawa area, Sichuan Province, Southwest China. Tibetan residents were selected by random sampling method from one city and six counties in Ngawa.

METHODS

Basic demographical information, physical activity and blood pressure were collected. In addition, the participants completed the questionnaire. A multivariate logistic regression analysis was used to examine the association between the prevalence, awareness, treatment and control rate of hypertension and the potential risk factors.

PARTICIPANTS

The sample comprised 2228 Ngawa Tibetan residents (age 18-80 years) from September 2018 to June 2019.

RESULTS

The prevalence rate of hypertension was 24.6%. The control rate was 6.2%, while the awareness rate (32.3%) and treatment rate (21.7%) of hypertension had been significantly improved.

CONCLUSION

The prevalence of hypertension among Ngawa Tibetans was high. The awareness and treatment were improved in recent years. But the control rate was low. The government needs to strengthen the basic medical care and health education for Ngawa Tibetans.

Association of age and blood pressure among 3.3 million adults: insights from China PEACE million persons project

OBJECTIVE

To assess the association between blood pressure (BP) with age and its heterogeneity across various sociodemographic subgroups in China.

METHODS

In this cross-sectional study, we analysed the data from nearly 3.3 million individuals aged 35-75 years from all 31 provinces in mainland China collected from September 2014 through August 2019. On the basis of possible combinations of eight characteristics and antihypertensive status, subgroups of at least 10 000 individuals were created and the age--blood pressure relationship was determined for each group.

RESULTS

The study included 3 291 058 participants (59.6% women), with a mean age of 55.8 ± 9.8 years. The prevalence of hypertension was 47.6%, of which 30.0% were taking antihypertensive medications. The mean SBP was 135.9 ± 20.2 mmHg. SBP increased at a mean unadjusted rate of 0.639 ± 0.001 mmHg/year. For 95% of the 25 145 subgroups, the SBP increased by 0.28--0.85 mmHg/year. The most common characteristics in the subgroups with the steepest association were female sex, rural area, low education, low-income family, Tibet region, and farmer occupation. The increase in SBP ranged from 0.13 to 0.41 mmHg/year for 95% of the treated subgroups and from 0.33 to 0.82 mmHg/year for 95% of the untreated subgroups.

CONCLUSION

Blood pressure is positively associated with age in this study, with almost three-fold variation across subgroups, indicating subgroup differences in biology, behaviour, or exposures. Antihypertension strongly blunts the association of age and blood pressure and diminishes the variation.

Barriers to Access to Treatment for Hypertensive Patients in Primary Health Care of Less Developed Northwest China: A Predictive Nomogram

Background

This study aims to evaluate the risk factors associated with untreated hypertension and develop and internally validate untreated risk nomograms in patients with hypertension among primary health care of less developed Northwest China.

Methods

A total of 895 eligible patients with hypertension in primary health care of less developed Northwest China were divided into a training set (n = 626) and a validation set (n = 269). Untreated hypertension was defined as not taking antihypertensive medication during the past two weeks. Using least absolute shrinkage and selection operator (LASSO) regression model, we identified the optimized risk factors of nontreatment, followed by establishment of a prediction nomogram. The discriminative ability, calibration, and clinical usefulness were determined using the area under the receiver operating characteristic curve (AUC), calibration curve, and decision analysis. The results were assessed by internal validation in the validation set.

Results

Five independent risk factors were derived from LASSO regression model and entered into the nomogram: age, herdsman, family income per member, altitude of habitation, and comorbidity. The nomogram displayed a robust discrimination with an AUC of 0.859 (95% confidence interval: 0.812–0.906) and good calibration. The nomogram was clinically useful when the intervention was decided at the untreated possibility threshold of 7% to 91% in the decision curve analysis. Results were confirmed by internal validation.

Conclusions

Our nomogram showed favorable predictive accuracy for untreated hypertension in primary health care of less developed Northwest China and might help primary health care assess the risk of nontreatment in patients with hypertension.

Coverage and effectiveness of hypertension screening in different altitudes of Tibet autonomous region

BACKGROUND

Tibet is an autonomous region in China located around an average altitude of 4500 m above sea level. Since 2012 the local government of Tibet has been providing free physical examinations, including screening for hypertension. However, the coverage and effectiveness of this free program have not been uncovered. This study aims to assess the coverage and effectiveness of hypertension screening and management program in 3 altitude levels of Tibet, and also the determinants of the success of the screening program.

METHODS

A stratified cluster survey was conducted among 1636 residents aged 18 years or over in three different altitude areas in Tibet. We adjusted for age and sex based on national census data and used weighted logistic regression models to find factors associated with hypertension screening.

RESULTS

The coverage of the hypertension screening program evaluated by participation rate in the previous screening was 94.9%, while 24.7% (95% CI: 22.1-27.3%) of them were diagnosed with hypertension. Females and alcohol drinkers were more likely to be screened. Among those diagnosed with hypertension, 28.7% had it under control. High altitude areas had a high proportion of controlled hypertension. The overall rate of controlled hypertension in high, moderate and low altitude areas was 35.1% (95% CI: 24.8-45.3%), 32.7% (95% CI: 22.2-43.2%) and 23.7% (95% CI: 14.7-32.6%), respectively. Younger aged persons were more likely to have better control of their hypertension.

CONCLUSIONS

The coverage of hypertension screening in Tibet was high, especially in the low altitude areas. However, the effectiveness of hypertension control was low, indicating a need to implement the treatment adherence routines into the current screening interventions.

Prevalence, Awareness, Treatment, Control, and Related Factors of Hypertension among Tajik Nomads Living in Pamirs at High Altitude

Background

Hypertension is a global problem, for which high-altitude residents exhibit higher burden. Hypertension in Tajik nomads from Pamirs with an average altitude above 4000 m remains less studied. We aimed to determine the prevalence, awareness, treatment, control, and risk factors associated with hypertension among Tajik population in Pamirs.

Methods

A cross-sectional survey was conducted between August and September 2015 using stratified three-stage random sampling in Taxkorgan county, Pamirs, China. Hypertension is defined as mean systolic and/or diastolic blood pressure (SBP, DBP) ≥140/90 mmHg and/or taking antihypertensive medication within the past two weeks. The prevalence (SBP ≥130 or DBP ≥80 mmHg) was also estimated using the 2017 American College of Cardiology (ACC)/American Heart Association (AHA) High Blood Pressure Guideline. The awareness, treatment, and control of hypertension and associated factors were evaluated.

Results

Totally, 797 subjects aged ≥18 years were enrolled with 46.3% men and 88.8% nomads with the mean age of 42.3 ± 15.2 years. The prevalence of hypertension was 24.2% (140/90 mmHg), and the prevalence was as high as 40.3%, based on the 2017 ACC/AHA guideline. Overall awareness, treatment, and control of hypertension were 52.8%, 40.9%, and 9.3%, respectively. In multivariate logistic regression, BMI ≥24.0 kg/m² (OR: 2.41, 95% CI: 1.44–4.04) was a risk factor for prehypertension, and age ≥60 years (OR: 2.04, 95% CI: 1.15–3.61), BMI ≥24.0 kg/m² (OR: 2.04, 95% CI: 1.15–3.61), and abdominal obesity (OR: 1.87, 95% CI: 1.09–3.22) were risk factors for hypertension. Angiotensin-converting enzyme inhibitors/angiotensin receptor blockers were the most commonly used antihypertensive medication (45.4%) as monotherapy, and 13.6% of treated hypertensive patients used two drugs.

Conclusions

There is a considerable prevalence of hypertension with low awareness, treatment, and control rates among Tajik nomads in Pamirs, where health programs improving the hypertension status are urgently needed, with the excess weight loss as a strategy.

The U-shaped association of altitudes with prevalence of hypertension among residents in Tibet, China

We aimed to evaluate the association of altitudes with the prevalence of hypertension among residents aged 15 years and above in Tibet, China. Data for 11,407 Tibetan residents from the National Health Services Survey in 2013 were analyzed. Association between altitudes and prevalence of physician-diagnosed hypertension was assessed by two logistic regression models as follows: (i) a base model adjusted for age and gender, and (ii) a full model additionally adjusted for body mass index, education, marital status, area of residence, distance to the nearest medical institute, smoking, drinking, and exercise. Nonlinear relationship between altitudes and prevalence of hypertension was explored by restricted cubic spline analyses. Sensitivity analyses were conducted by restricting to residents of rural and/or nomadic areas. The prevalence of hypertension was estimated to be 37.6%. We found a U-shaped association between altitudes and prevalence of physician-diagnosed hypertension with a turning point at around 3800 m (12,467 ft). For residents living above 3800 m, a 1000 m increase in altitudes was associated with 2.05 (95% confidence interval [CI]: 1.62-2.61) times higher odds of having physician-diagnosed hypertension, after adjusting for age and gender. When further controlling for all covariates, the odds ratio (OR) dropped to 1.87 (95% CI: 1.46-2.41). For residents living below 3800 m, a 1000 m increase was associated with 0.29 (95% CI: 0.19-0.44) times less likelihood of having physician-diagnosed hypertension in the full model. Sensitivity analyses among residents in rural and/or nomadic areas showed similar associations. To conclude, altitudes were in a U-shaped association with prevalence of hypertension.

Neural network correlates of high-altitude adaptive genetic variants in Tibetans: A pilot, exploratory study

Although substantial progress has been made in the identification of genetic substrates underlying physiology, neuropsychology, and brain organization, the genotype–phenotype associations remain largely unknown in the context of high‐altitude (HA) adaptation. Here, we related HA adaptive genetic variants in three gene loci (EGLN1, EPAS1, and PPARA) to interindividual variance in a set of physiological characteristics, neuropsychological tests, and topological attributes of large‐scale structural and functional brain networks in 135 indigenous Tibetan highlanders. Analyses of individual HA adaptive single‐nucleotide polymorphisms (SNPs) revealed that specific SNPs selectively modulated physiological characteristics (erythrocyte level, ratio between forced expiratory volume in the first second to forced vital capacity, arterial oxygen saturation, and heart rate) and structural network centrality (the left anterior orbital gyrus) with no effects on neuropsychology or functional brain networks. Further analyses of genetic adaptive scores, which summarized the overall degree of genetic adaptation to HA, revealed significant correlations only with structural brain networks with respect to local interconnectivity of the whole networks, intermodule communication between the right frontal and parietal module and the left occipital module, nodal centrality in several frontal regions, and connectivity strength of a subnetwork predominantly involving in intramodule edges in the right temporal and occipital module. Moreover, the associations were dependent on gene loci, weight types, or topological scales. Together, these findings shed new light on genotype–phenotype interactions under HA hypoxia and have important implications for developing new strategies to optimize organism and tissue responses to chronic hypoxia induced by extreme environments or diseases.

Characteristics of Cerebral Stroke in the Tibet Autonomous Region of China

It is well known that cerebrovascular disease has become an important cause of adult death and disability. Strikingly, the Tibet Autonomous Region (TAR) ranks on the top in China for the incidence of stroke. To help explain this phenomenon, we have searched for and analyzed stroke-related literature for the TAR in the past 2 decades and have referenced reports from other regions at similar altitudes. This article focuses on epidemiology features, risk factors, and pathogenesis of stroke in the TAR in an effort to generate a better understanding of the characteristics of stroke in this region. The special plateau-related factors such as its high elevation, limited oxygen, the high incidence of hypertension, smoking, and the unique dietary habits of the region are correlated with the high incidence of stroke. In addition to these factors, the pathogenesis of stroke in this high-altitude area is also unique. However, there is no established explanation for the unique occurrence and high incidence of stroke in the TAR. Our study provides an important rationale not only for the clinic to prevent and treat this disease, but also for the government to develop appropriate health policies for the prevention of stroke in the TAR.

Blood pressure level increase with altitude in three argentinean indigenous communities

Objective

To compare blood pressure (BP) levels in three groups of Argentinean Indigenous schoolchildren from similar ethnic backgrounds but living at three different altitudes.

Methods

A cross-sectional study compared 185 (83 females) children aged 5–14 years from San Antonio de los Cobres (SAC), 3750 m above sea level; 46 (23 females) from Cobres, 3450 m; and 167 (83 females) from Chicoana (CH), 1400 m. Anthropometric and BP measurements were performed.

Results

The prevalence of overweight/obesity was lower in SAC (6.5% [12]) and Cobres (4.3% [2]) than in CH (24% [24]) (BMI > 85 percentile per CDC norms). Systolic BP increased significantly with altitude: (SAC 86 mm Hg, Cobres 77 mm Hg, and CH 69 mm Hg). Similar results were obtained with diastolic BP (SAC 57 mm Hg, Cobres 51 mm Hg, and CH 47 mm Hg) and with median arterial pressure (MAP) (SAC 67 mm Hg, Cobres 60 mm Hg, and CH 55 mm Hg). Multiple linear regression analyses showed that altitude was significantly and independently associated with children's systolic BP (beta 10.56; R² = 0.40), diastolic BP (beta 6.27; R² = 0.25) and MAP (beta 7.69; R² = 0.32); adjusted for age, sex, and BMI.

Conclusions

We found that as altitude increased, BP levels increased significantly in indigenous children from similar backgrounds living permanently at different altitudes.

Screening for Developmental Dysplasia of the Hip in Infants in Tibet Identifies Increased Prevalence Associated with Altitude

BACKGROUND Developmental dysplasia of the hip (DDH), also known as congenital hip dislocation or congenital hip dysplasia is usually diagnosed at birth. Studies on DDH at high-altitude are rare. Tibetans live mainly at altitudes above 3,500 m, and the prevalence of DDH in this population is not currently known. This cross-sectional epidemiological study aimed to identify the prevalence and associated risk factors for DDH in Tibet. MATERIAL AND METHODS Between 1st June 2015 and 30 June 2016, infants in Tibet aged between 0-6 months and from ten districts at different altitudes in Shigatse, Tibet were referred to our hospital for the assessment of DDH. All the infants underwent clinical evaluation for DDH and ultrasound testing using the Graf method. RESULTS There were 606 infants who met the study inclusion criteria, including 253 female infants and 353 male infants, of which 106 infants had DDH. The prevalence of DDH in Shigatse, Tibet was approximately 174.9/1000 infants (106/606). Altitude was strongly associated with increased risk of DDH in Tibet (r=0.82, P=0.004). CONCLUSIONS This is the first epidemiological study of DDH in the Tibetan population. The results showed that DDH is prevalent among native Tibetan people in Shigatse, and there was a significant correlation between altitude and the prevalence of DDH. Further studies are needed to investigate the mechanism of the association between altitude and the increased incidence of DDH in infants.

Association between homocysteine level and blood pressure traits among Tibetans: A cross-sectional study in China

Studies on hypertension (HTN) in Tibetans who live in high altitude areas are less and whether total homocysteine level (tHcy) is associated with blood pressure (BP) levels or HTN status in Tibetans is unknown.A total of 1486 Tibetans with complete information from a cross-sectional survey conducted in Lhasa Chengguan County of Tibet were included in this study. Demographic data, self-reported history of disease, and life styles were collected using a questionnaire. Blood tHcy, creatinine, fasting plasma-glucose, total cholesterol, triglycerides, and BP were measured with equipment.The median tHcy level of the whole population was 14.60 (13.17-16.50) μmol/L, and the prevalence of HTN was 26.99%. Regression models, adjusted for possible covariates, showed that an average increase of 1 lnHcy (log transformation of tHcy level) was associated with an increase of 3.78 mmHg of systolic BP (SBP, P = .011) and 3.02 mmHg of diastolic BP (DBP, P = .003). The prevalence of HTN, levels of SBP and DBP in the third (OR for HTN: 1.60, P = .026; β for SBP: 3.41, P = .004; β for DBP: 2.57, P = .002) and fourth (OR for HTN: 2.19, P < .001; β for SBP: 5.08, P < .001; β for DBP: 3.09, P < .001) quartile of tHcy level were higher than those in the first quartile.THcy is associated with BP levels and HTN status among Tibetans. Both HTN management and tHcy level should be paid more attention in Tibetans.

Distress tolerance moderates the relationship between anger experience and elevated blood pressure

Previous studies have linked anger to elevated blood pressure. However, the nature of the association between anger and elevated blood pressure is unclear. This study is aimed at investigating the moderating effect of distress tolerance on the relationship between anger experience and elevated blood pressure. A total of 310 patients drawn from a university teaching hospital in southeast Nigeria participated in this study. They comprised 156 men and 154 women who were aged between 20 and 80 years (mean age = 50.45). Participants responded to the measures of distress tolerance and Novaco Anger Inventory—Short Form. The blood pressures of the participants were obtained with sphygmomanometer and stethoscope. The results of the hierarchical multiple regression analysis indicated that anger experience significantly predicted both systolic and diastolic blood pressure. The results also showed that distress tolerance was a significant predictor of systolic and diastolic blood pressure. Distress tolerance moderated the relationship between anger experience and systolic and diastolic blood pressure. The relationships between anger and systolic and diastolic pressure were stronger for patients with low distress tolerance compared to patients with high distress tolerance. It is recommended that psychological interventions aimed at increasing people’s level of distress tolerance are emphasized in the management of elevated blood pressure.

Blood pressure and hypertension in people living at high altitude in Nepal

This study aimed to describe blood pressure (BP) and hypertension (HT) in samples of high altitude populations of Nepal and to explore associations of systolic and diastolic BP with altitude. This was a cross-sectional survey of cardiovascular disease and associated risk factors among 521 people living at four different altitude levels, all above 2800 m, in the Mustang and Humla districts of Nepal. Data on BP was available for all 521 participants. Systolic and diastolic BP levels were highest at the altitude of 3620 m (the highest area surveyed) but did not consistently increase with altitude. Using the cut-point of ≥ 140/90 mmHg (systolic/diastolic), the prevalence of HT (or on anti-hypertensive medication) was 46.1%, 40.9% and 54.5%, respectively, at 2800, 3270 and 3620 m of Mustang district, and 29.1% at 2890 m of Humla district. In a multivariate model adjusting for potential confounders, there was strong evidence of a relationship between systolic BP and altitude; mean systolic BP increased by 15.6 mmHg (95% CI: 4.0-27.2), P = 0.009 for every 1000 m elevation. Although diastolic BP and the probability for HT or on anti-hypertensive medication also tended to increase with increasing altitude levels, there was no evidence of a relationship. In the present study three out of four communities living at higher altitude levels showed a greater prevalence of HT among those aged 30 years or older compared with the overall national data. These findings indicate a probable high risk of raised BP in high altitude populations in Nepal.

Association of with-no-lysine kinase 1 and Serine/Threonine kinase 39 gene polymorphisms and haplotypes with essential hypertension in Tibetans

Tibetans have a higher essential hypertension prevalence compared with other ethnics in China. The reason might be due to their unique environmental influence, as well as genetic factor. However, limited studies focus on Tibetan genetics and its association with hypertension. The aim of this study was to investigate the association between With-No-Lysine (K) Kinase 1 (WNK1), Serine/Threonine kinase 39(STK39) genes variants and hypertension in the Tibetan population. 204 Tibetan hypertensive patients and 305 normotensive controls were recruited in an epidemiological survey conducted at 2 sites in the Ganzi Tibetan autonomous region. Patients were genotyped for nineteen WNK1 candidate tag single nucleotide polymorphisms (SNPs) and three STK39 SNPs, and haplotype analysis was performed. Results showed that the allele A in rs1468326 was overrepresented in hypertensive patients versus control (53.4% vs 42.9%, P < 0.05). The multivariable-adjusted odds ratio (OR) for hypertension among CA + AA genotypes carriers was 1.60 (95% CI: 1.02-2.62, P < 0.05), and they also had a higher systolic blood pressure (136.5 ± 28.6 vs 131.7 ± 24.8 mmHg, P < 0.05). However, the TT genotype ratio in rs6749447 was lower in hypertensives (5.4% vs 10.8%, P < 0.05), and the hypertension risk for the TT genotype carriers in rs6749447 decreased after adjustment (OR 0.49, 95% CI 0.19-0.95, P < 0.05). Subjects with haplotype AGACAGGAATCGT showed 1.57 times higher risk of hypertension (95% CI 1.02-2.41, P < 0.05). In conclusion, SNP rs1468326 of WNK1, rs6749447 of STK39, and WNK1 haplotype AGACAGGAATCGT were associated with hypertension in Tibetan individuals. Environ. Mol. Mutagen. 59:151-160, 2018. © 2017 Wiley Periodicals, Inc.

A qualitative evaluation of a simplified cardiovascular management program in Tibet, China

BACKGROUND

The simplified cardiovascular management (SimCard Study) program was a cluster randomized controlled trial conducted in Tibet, China to evaluate a multifaceted intervention consisting of appropriate medication prescriptions and lifestyle recommendations delivered by village doctors. The intervention was effective in improving the management of cardiovascular diseases in resource-limited settings. The aim of this qualitative study was to examine stakeholder feedback and to inform future research and scaling up.

METHOD

A total of 28 face-to-face individual interviews were conducted. The interviews were conducted in 6 out of 14 intervention villages by 2 interviewers who speak the local language. Participants included 18 community members at high risk of CVD, 6 village doctors, 2 local project coordinators, and 2 county officials. Interview guides were used to facilitate the interview covering the focus of perceived usefulness and content of the intervention, fidelity to the intervention, and potential scalability of the intervention. Qualitative interviews were coded using thematic analysis.

RESULTS

The average age of the participants was 41 years and 70% were female. Our findings showed that the intervention was delivered according to the protocol and was described as a useful program for CVD management by both high-risk individuals and village doctors. However, lack of knowledge among high-risk individuals, insufficient availability of healthcare providers, inadequate financial incentive, and incomplete infrastructure such as difficulty in transportation and cell phone signal were identified as the main barriers to successful implementation and scale-up.

CONCLUSION

The intervention was implemented in line with the protocol and provided substantial benefits for relevant community members and health professionals. However, multiple health system barriers need to be addressed for successful scale-up in rural China.

TRIAL REGISTRATION

Unique identifier: NCT01503814 . Registered 11 December 2011.

CYP11B2 gene polymorphism and essential hypertension among Tibetan, Dongxiang and Han populations from northwest of China

Essential hypertension (EH) is a complex multifactorial condition influenced by both genetic and environmental factors; aldosterone synthase (CYP11B2) is a key enzyme which involves in the terminal steps of aldosterone synthesis. The result of relationship between C-344T of CYP11B2 polymorphism and EH was controversial. This study was undertaken to investigate the association of C-344T polymorphism with EH in the populations of Tibetan, Dongxiang and Han from northwest of China. A total of 2115 participants aged 18-70 years were enrolled in this study. In total, 1776 blood samples, including 545 Tibetan (305 hypertensive and 240 normotensive), 530 Dongxiang (254 hypertensive and 276 normotensive) and 701 Han (338 hypertensive and 363 normotensive), were analyzed successfully by using Snapshot minisequencing method, 30 samples were also performed by direct sequencing (5 hypertensive and 5 normotensive in each population, respectively). The frequencies of genotype and allele of CYP11B2 (C-344T) were not significantly different between EH group and control group in every ethnic population (p > 0.05). However, in female population of Tibetan, the frequencies of CC and CT genotype and C allele in EH group were higher than in control (p < 0.05) group. The frequencies of CC genotype and C allele in both the normotensive controls and EH patients in Tibetan population were higher than in Dongxiang and Han populations. Our study suggests that there is lack of association between C-344T polymorphism of CYP11B2 gene and EH in Dongxiang and Han populations, whereas the polymorphism was correlated with EH in female population of Tibetan.

Awareness Status of Chronic Disabling Neurological Diseases among Elderly Veterans

Background:

The awareness, treatment and prevention of chronic diseases are generally poor among the elderly population of China, whereas the prevention and control of chronic diseases in elderly veteran communities have been ongoing for more than 30 years. Therefore, investigating the awareness status of chronic disabling neurological diseases (CDND) and common chronic diseases (CCD) among elderly veterans may provide references for related programs among the elderly in the general population.

Methods:

A cross-sectional survey was conducted among veterans ≥60 years old in veteran communities in Beijing. The awareness of preventive strategies against dementia, Alzheimer's disease (AD), Parkinson's disease (PD), sleep disorders, cerebrovascular disease (CVD) and CCD such as hypertension, and the approaches used to access this information, including media, word of mouth (verbal communication among the elderly) and health care professionals, were investigated via face-to-face interviews.

Results:

The awareness rates for CCD and CVD were approximately 100%, but that for AD was the lowest at <10%. The awareness rates for sleep disorders, PD and dementia, were 51.0–89.4%. Media was the most commonly selected mode of communication by which veterans acquired knowledge about CCD and CVD. Media was used by approximately 80% of veterans. Both health care professionals and word of mouth were used by approximately 50% of veterans. With respect to the source of information about CDND excluding AD, the rates of the use of health care professionals, word of mouth and media were 10.6–28.2%, 56.5–76.5%, and approximately 50%, respectively.

Conclusions:

The awareness of CDND among elderly veterans was significantly lower than that of CCD. More information about CDND should be disseminated by health care professionals. Appropriate guidance will promote the rapid and extensive dissemination of information about the prevention of CDND by media and word-of-mouth peer education.

The Expanding Burden of Elevated Blood Pressure in China: Evidence From Jiangxi Province, 2007-2010

Elevated blood pressure (BP) as a risk factor accounts for the biggest burden of disease worldwide and in China. This study aimed to estimate attributed mortality and life expectancy (LE) to elevated BP in Jiangxi province between 2007 and 2010. BP and mortality data (2007 and 2010 inclusive) were obtained from the National Chronic Diseases and Risk Factors Surveillance Survey and Disease Surveillance Points system, respectively. Population-attributable fraction used in comparative risk assessment of the Global Burden of Disease study 2010 were followed to quantify the attributed mortality to elevated BP, subsequently life table methods were applied to estimate its effects on LE. Uncertainty analysis was conducted to get 95% uncertainty intervals (95% uncertainty interval [UI]) for each outcome. There are 35,482 (95% UI: 31,389-39,928) and 47,842 (42,323-53,837) deaths in Jiangxi province were caused by elevated BP in 2007 and 2010, respectively. 2.24 (1.87-2.65) years of LE would be gained if all the attributed deaths were eliminated in 2007, and increased to 3.04 (2.52-3.48) in 2010. If the mean value of elevated BP in 2010 was decreased by 5 and 10 mm Hg, 5324 (4710-5991) and 11,422 (10,104-12,853) deaths would be avoided, with 0.41 (0.37-0.48) and 0.85 (0.71-1.09) years of LE gained, respectively. The deaths attributable to elevated BP in Jiangxi province has increased by 35% from 2007 to 2010, with 0.8 years of LE loss, suggesting the necessity to take actions to control BP in Chinese population.

A Cluster-Randomized, Controlled Trial of a Simplified Multifaceted Management Program for Individuals at High Cardiovascular Risk (SimCard Trial) in Rural Tibet, China, and Haryana, India

BACKGROUND

In rural areas in China and India, the cardiovascular disease burden is high but economic and healthcare resources are limited. This study (the Simplified Cardiovascular Management Study [SimCard]) aims to develop and evaluate a simplified cardiovascular management program delivered by community health workers with the aid of a smartphone-based electronic decision support system.

METHODS AND RESULTS

The SimCard study was a yearlong cluster-randomized, controlled trial conducted in 47 villages (27 in China and 20 in India). Recruited for the study were 2086 individuals with high cardiovascular risk (aged ≥40 years with self-reported history of coronary heart disease, stroke, diabetes mellitus, and/or measured systolic blood pressure ≥160 mm Hg). Participants in the intervention villages were managed by community health workers through an Android-powered app on a monthly basis focusing on 2 medication use and 2 lifestyle modifications. In comparison with the control group, the intervention group had a 25.5% (P<0.001) higher net increase in the primary outcome of the proportion of patient-reported antihypertensive medication use pre- and post-intervention. There were also significant differences in certain secondary outcomes: aspirin use (net difference: 17.1%; P<0.001) and systolic blood pressure (-2.7 mm Hg; P=0.04). However, no significant changes were observed in the lifestyle factors. The intervention was culturally tailored, and country-specific results revealed important differences between the regions.

CONCLUSIONS

The results indicate that the simplified cardiovascular management program improved quality of primary care and clinical outcomes in resource-poor settings in China and India. Larger trials in more places are needed to ascertain the potential impacts on mortality and morbidity outcomes.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01503814.

Prevalence and Clustering of Cardiovascular Disease Risk Factors among Tibetan Adults in China: A Population-Based Study

Objectives

The prevalence of cardiovascular disease risk factors has increased worldwide. However, the prevalence and clustering of cardiovascular disease risk factors among Tibetans is currently unknown. We aimed to explore the prevalence and clustering of cardiovascular disease risk factors among Tibetan adults in China.

Methods

In 2011, 1659 Tibetan adults (aged ≥18 years) from Changdu, China were recruited to this cross-section study. The questionnaire, physical examinations and laboratory testing were completed and the prevalence of cardiovascular disease risk factors, including hypertension, diabetes, overweight/obesity, dyslipidemia, and current smoking, were counted. The association between the clustering of cardiovascular disease risk factors and demographic characteristics, and geographic altitude were assessed.

Results

The age-standardized prevalence of hypertension, diabetes, overweight or obesity, dyslipidemia, and current smoking were 62.4%, 6.4%, 34.3%, 42.7%, and 6.1%, respectively, and these risk factors were associated with age, gender, education level, yearly family income, altitude, occupation, and butter tea consumption (P < 0.05). Overall, the age-adjusted prevalence of clustering of ≥1, ≥2, and ≥3 cardiovascular disease risk factors were 79.4%, 47.1%, and 20.9%, respectively. There appeared higher clustering of ≥2 and ≥3 cardiovascular disease risk factors among Tibetans with higher education level and family income yearly, and those living at an altitude < 3500 m and in a township.

Conclusions

The prevalence of cardiovascular disease risk factors, especially hypertension, was high in Tibetans. Moreover, there was an increased clustering of cardiovascular disease risk factors among those with higher socioeconomic status, lamas and those living at an altitude < 3500 m. These findings suggest that without the immediate implementation of an efficient policy to control these risk factors, cardiovascular disease will eventually become a major disease burden among Tibetans.

Prevalence, awareness, treatment and control of hypertension in Tibetan monks from Gansu Province, Northwest China

Tibetan monks are a special group in life style and diet customs. We have little information of hypertension about them. Therefore, the objective of this study was to investigate the information on the prevalence, awareness, treatment and control of hypertension in these populations. A cross-sectional study of hypertension was carried out in 984 monks and 1042 Tibetan residents' controls in the same area. All the subjects were selected for interview, and physical examination involved blood pressure (BP) measurement. The overall prevalence of hypertension in monks was significantly lower than those in local residents (19.3% versus 34.1%; p < 0.01). The rates of awareness, treatment and control in monks were also lower than those in local residents (9.5% versus 16.9%, 4.2% versus 13.2% and 1.6% versus 4.5%; p < 0.01 for each). These findings indicated that a low prevalence of hypertension among monks aged 18 years and over in Gannan Tibetan autonomous district of Gansu province in China. We concluded that the relatively healthy diet and ways of life in monks were the major contributing factors to the lower prevalence of hypertension. However, the awareness, treatment and control rates of hypertension were also low. The possible reasons were most likely due to the difficult access to quality medical care and poor health education.

Relationship between altitude and the prevalence of hypertension in Tibet: a systematic review

Introduction

Hypertension is a leading cause of cardiovascular disease, which is the cause of one-third of global deaths and is a primary and rising contributor to the global disease burden. The objective of this systematic review was to determine the prevalence and awareness of hypertension among the inhabitants of Tibet and its association with altitude, using the data from published observational studies.

Methods

We conducted electronic searches in Medline, Embase, ISI Web of Science and Global Health. No gender or language restrictions were imposed. We assessed the methodological characteristics of included studies using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) criteria. Two reviewers independently determined the eligibility of studies, assessed the methodology of included studies and extracted the data. We used meta-regression to estimate the degree of change in hypertension prevalence with increasing altitude.

Results

We identified 22 eligible articles of which eight cross-sectional studies with a total of 16 913 participants were included. The prevalence of hypertension ranged between 23% and 56%. A scatter plot of altitude against overall prevalence revealed a statistically significant correlation (r=0.68; p=0.04). Meta-regression analysis revealed a 2% increase in the prevalence of hypertension with every 100 m increase in altitude (p=0.06). The locations and socioeconomic status of subjects affected the awareness and subsequent treatment and control of hypertension.

Conclusions

The results from cross-sectional studies suggest that there is a significant correlation between altitude and the prevalence of hypertension among inhabitants of Tibet. The socioeconomic status of the inhabitants can influence awareness and management of hypertension. Very little research into hypertension has been conducted in other prefectures of Tibet where the altitude is much higher. Further research examining the impact of altitude on blood pressure is warranted.

Systolic hypertension: an increasing clinical challenge in Asia

Systolic hypertension, the predominant form of hypertension in patients aged over 50-60 years, is a growing health issue as the Asian population ages. Elevated systolic blood pressure is mainly caused by arterial stiffening, resulting from age-related vascular changes. Elevated systolic pressure increases the risk of cardiovascular disease, mortality and renal function decline, and this risk may increase at lower systolic pressure levels in Asian than Western subjects. Hence, effective systolic pressure lowering is particularly important in Asians yet blood pressure control remains inadequate despite the availability of numerous antihypertensive medications. Reasons for poor blood pressure control include low awareness of hypertension among health-care professionals and patients, under-treatment, and tolerability problems with antihypertensive drugs. Current antihypertensive treatments also lack effects on the underlying vascular pathology of systolic hypertension, so novel drugs that address the pathophysiology of arterial stiffening are needed for optimal management of systolic hypertension and its cardiovascular complications.

Using a low-sodium, high-potassium salt substitute to reduce blood pressure among Tibetans with high blood pressure: a patient-blinded randomized controlled trial

Objectives

To evaluate the effects of a low-sodium and high-potassium salt-substitute on lowering blood pressure (BP) among Tibetans living at high altitude (4300 meters).

Method

The study was a patient-blinded randomized controlled trial conducted between February and May 2009 in Dangxiong County, Tibetan Autonomous Region, China. A total of 282 Tibetans aged 40 or older with known hypertension (systolic BP≥140 mmHg) were recruited and randomized to intervention (salt-substitute, 65% sodium chloride, 25% potassium chloride and 10% magnesium sulfate) or control (100% sodium chloride) in a 1: 1 allocation ratio with three months’ supply. Primary outcome was defined as the change in BP levels measured from baseline to followed-up with an automated sphygmomanometer. Per protocol (PP) and intention to treat (ITT) analyses were conducted.

Results

After the three months’ intervention period, the net reduction in SBP/DBP in the intervention group in comparison to the control group was −8.2/−3.4 mmHg (all p<0.05) in PP analysis, after adjusting for baseline BP and other variables. ITT analysis showed the net reduction in SBP/DBP at −7.6/−3.5 mmHg with multiple imputations (all p<0.05). Furthermore, the whole distribution of blood pressure showed an overall decline in SBP/DBP and the proportion of patients with BP under control (SBP/DBP<140 mmHg) was significantly higher in salt-substitute group in comparison to the regular salt group (19.2% vs. 8.8%, p = 0.027).

Conclusion

Low sodium high potassium salt-substitute is effective in lowering both systolic and diastolic blood pressure and offers a simple, low-cost approach for hypertension control among Tibetans in China.

Trial Registration

ClinicalTrials.gov NCT01429246

A cluster-randomized controlled trial to evaluate the effects of a simplified cardiovascular management program in Tibet, China and Haryana, India: study design and rationale

Background

In resource-poor areas of China and India, the cardiovascular disease burden is high, but availability of and access to quality healthcare is limited. Establishing a management scheme that utilizes the local infrastructure and builds healthcare capacity is essential for cardiovascular disease prevention and management. The study aims to develop, implement, and evaluate the feasibility and effectiveness of a simplified, evidence-based cardiovascular management program delivered by community healthcare workers in resource-constrained areas in Tibet, China and Haryana, India.

Methods/design

This yearlong cluster-randomized controlled trial will be conducted in 20 villages in Tibet and 20 villages in Haryana. Randomization of villages to usual care or intervention will be stratified by country. High cardiovascular disease risk individuals (aged 40 years or older, history of heart disease, stroke, diabetes, or measured systolic blood pressure of 160 mmHg or higher) will be screened at baseline. Community health workers in the intervention villages will be trained to manage and follow up high-risk patients on a monthly basis following a simplified ‘2 + 2’ intervention model involving two lifestyle recommendations and the appropriate prescription of two medications. A customized electronic decision support system based on the intervention strategy will be developed to assist the community health workers with patient management. Baseline and follow-up surveys will be conducted in a standardized fashion in all villages. The primary outcome will be the net difference between-group in the proportion of high-risk patients taking antihypertensive medication pre- and post-intervention. Secondary outcomes will include the proportion of patients taking aspirin and changes in blood pressure. Process and economic evaluations will also be conducted.

Discussion

To our knowledge, this will be the first study to evaluate the effect of a simplified management program delivered by community health workers with the help of electronic decision support system on improving the health of high cardiovascular disease risk patients. If effective, this intervention strategy can serve as a model that can be implemented, where applicable, in rural China, India, and other resource-constrained areas.

Trial registration

The trial was registered in the clinicaltrials.gov database on 30 December, 2011 and the registration number is NCT01503814.

Prevalence of metabolic syndrome and common metabolic components in high altitude farmers and herdsmen at 3700 m in Tibet

OBJECTIVES

To estimate the prevalence of metabolic syndrome, its associated factors and components in 30-80-year-old Tibetans living at high altitude.

METHOD

Multistage sampling of 692 participants. We used IDF criteria for estimation of the metabolic syndrome, and a questionnaire based on the WHO MONICA protocol.

RESULTS

The prevalence of metabolic syndrome was 8.2% (Confidence interval (CI):6.1-10.2) while the common components were: fasting hyperglycemia 57.5% (53.8-61.1); abdominal obesity 46% (42.2-49.7); and high blood pressure 37% (33.4-40.5). Metabolic syndrome was significantly lower for males, those with higher education and physical activity >2000 Kcal/week. Self awareness, treatment and control were low for both diabetes and lipid abnormality.

CONCLUSION

The overall prevalence of metabolic syndrome in high altitude farmers and herdsmen in Tibet was lower compared to other high altitude natives, while its components (hyperglycemia, obesity, and high blood pressure) were higher than in other high altitude communities. Implications of the findings of high prevalence of smoking (among men), obesity, and hypertension and low rates of awareness, treatment, and control of the components of the metabolic syndrome among rural highlanders propels the need for health programs targeting risk factors.

Cardiovascular and renal effects of chronic exposure to high altitude

Over 140 million people live at high altitude, defined as living at an altitude of 2400 m or more above sea level. Subjects living under these conditions are continuously living under hypoxic conditions and, depending on the population, various adaptations have developed. Interestingly, subjects living chronically at high altitude appear to have a decreased frequency of obesity, diabetes and coronary artery disease. However, these benefits on health are balanced by the frequent development of systemic and pulmonary hypertension. Recently, it has been recognized that subjects living at high altitude are at risk for developing high-altitude renal syndrome (HARS), which is a syndrome consisting of polycythemia, hyperuricemia, systemic hypertension and microalbuminuria, but with preserved glomerular filtration rate. More studies should be performed to characterize the mechanisms and etiology of HARS; as such studies may be of benefit not only to the high-altitude population, but also to better understanding of the renal consequences of acute and chronic hypoxia.

Performance comparison among the major healthcare financing systems in six cities of the Pearl River Delta region, mainland China

Background

The healthcare system of mainland China is undergoing drastic reform and the optimal models for healthcare financing for provision of primary care will need to be identified. This study compared the performance indicators of the community health centres (CHCs) under different healthcare financing systems in the six cities of the Pearl River Delta region.

Methods

Approximately 300 hypertensive patients were randomly recruited from the computerized chronic disease management records provided by one CHC in each of the six cities in 2011 using a multi-stage cluster random sampling method. The major outcome measures included the treatment rate of hypertension, defined as prescription of ≥ one antihypertensive agent; and the control rate of hypertension, defined as systolic blood pressure levels <140 mmHg and diastolic blood pressure levels <90 mmHg in patients without diabetes mellitus, or <130/80 mmHg among patients with concomitant diabetes. Binary logistic regression analyses were conducted with these two measures as outcome variables, respectively, controlling for patients’ socio-demographic variables. The financing system (Hospital- vs. Government- vs. private-funded) was the independent variable tested for association with the outcomes.

Results

From 1,830 patients with an average age of 65.9 years (SD 12.8), the overall treatment and control rates were 75.4% and 20.2%, respectively. When compared with hospital-funded CHCs, patients seen in the Government-funded (adjusted odds ratio [AOR] 0.462, 95% C.I. 0.325–0.656) and private-funded CHCs (AOR 0.031, 95% C.I. 0.019–0.052) were significantly less likely to be prescribed antihypertensive medication. However, the Government-funded CHC was more likely to have optimal BP control (AOR 1.628, 95% C.I. 1.157–2.291) whilst the privately-funded CHC was less likely to achieve BP control (AOR 0.146, 95% C.I. 0.069–0.310), irrespective of whether antihypertensive drugs were prescribed.

Conclusions

Privately-funded CHCs had the lowest rates of BP treatment and control due to a variety of potential factors as discussed.