Lifestyle improvement and the reduced risk of cardiovascular disease: the China-PAR project.

BACKGROUND: The benefits of healthy lifestyles are well recognized. However, the extent to which improving unhealthy lifestyles reduces cardiovascular disease (CVD) risk needs to be discussed. We evaluated the impact of lifestyle improvement on CVD incidence using data from the China-PAR project (Prediction for Atherosclerotic Cardiovascular Disease Risk in China). METHODS: A total of 12,588 participants free of CVD were followed up for three visits after the baseline examination. Changes in four lifestyle factors (LFs) (smoking, diet, physical activity, and alcohol consumption) were assessed through questionnaires from the baseline to the first follow-up visit. Cox proportional hazard models were used to estimate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs). The risk advancement periods (RAPs: the age difference between exposed and unexposed participants reaching the same incident CVD risk) and population-attributable risk percentage (PAR%) were also calculated. RESULTS: A total of 909 incident CVD cases occurred over a median follow-up of 11.14 years. Compared with maintaining 0-1 healthy LFs, maintaining 3-4 healthy LFs was associated with a 40% risk reduction of incident CVD (HR = 0.60, 95% CI: 0.45-0.79) and delayed CVD risk by 6.31 years (RAP: -6.31 [-9.92, -2.70] years). The PAR% of maintaining 3-4 unhealthy LFs was 22.0% compared to maintaining 0-1 unhealthy LFs. Besides, compared with maintaining two healthy LFs, improving healthy LFs from 2 to 3-4 was associated with a 23% lower risk of CVD (HR = 0.77, 95% CI: 0.60-0.98). CONCLUSIONS: Long-term sustenance of healthy lifestyles or improving unhealthy lifestyles can reduce and delay CVD risk.

Effects of the total physical activity and its changes on incidence, progression, and remission of hypertension.

OBJECTIVES: Moderate to vigorous physical activity is recommended to prevent hypertension according to the current guidelines. However, the degree to which the total physical activity (TPA) and its changes benefit normotensives and hypertensives is uncertain. We aimed to examine the effects of TPA and its changes on the incidence, progression, and remission of hypertension in the large-scale prospective cohorts. METHODS: A total of 73,077 participants (55,101 normotensives and 17,976 hypertensives) were eligible for TPA analyses. During a mean follow-up of 7.16 years (394,038 person-years), 12,211 hypertension cases were identified. TPA was estimated as metabolic equivalents and categorized into quartiles. Cox proportional hazards regression and multivariable logistic regression were used to estimate associations of TPA and changes in TPA with incident hypertension and progression/remission of hypertension. RESULTS: Compared with the lowest quartile of TPA, normotensives at the third and the highest quartile had a decreased risk of incident hypertension, with hazard ratios (HRs) of 0.86 [95% confidence interval (CI): 0.81-0.91] and 0.81 (95% CI: 0.77-0.86), respectively. Hypertensives at the highest quartile of TPA demonstrated a decreased risk of progression of hypertension [odds ratio (OR) = 0.87, 95% CI: 0.79-0.95], and an increased probability of hypertension remission (OR = 1.17, 95% CI: 1.05-1.29). Moreover, getting active from a sedentary lifestyle during the follow-up period could reduce 25% (HR = 0.75, 95% CI: 0.58-0.96) risk of incident hypertension, whereas those becoming sedentary did not achieve benefit from initially being active. CONCLUSIONS: Our findings indicated that increasing and maintaining TPA levels could benefit normotensives, whereas higher TPA levels were needed to effectively control progression and improve remission of hypertension. Physical activity played undoubtedly an essential role in both primary and secondary prevention of hypertension.

Association of cardiovascular diseases with milk intake among general Chinese adults.

BACKGROUND: The association of milk intake with cardiovascular disease (CVD) and cause-specific mortality remained controversial and evidence among the Chinese population was limited. We aimed to study the relationship between milk intake and CVDs among general Chinese adults. METHODS: A total of 104,957 participants received questionnaire survey. Results of physical examination such as anthropometric measurements and biochemical tests during 2007 to 2008, demographic data and their information on milk intake were collected through standardized questionnaires. Cox proportional hazard regression models were used to calculate hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs) of CVD incidence, cause-specific mortality and all-cause mortality related to milk intake. Restricted cubic splines (RCSs) were applied to examine dose-response associations. RESULTS: Among the 91,757 participants with a median follow-up period of 5.8 years, we documented 3877 CVD cases and 4091 all-cause deaths. Compared with participants who never consumed milk, the multivariate-adjusted HRs (95% CIs) of CVD incidence for 1 to 150 g/day, 151 to 299 g/day, and ≥300 g/day were 0.94 (0.86-1.03) (P > 0.05), 0.77 (0.66-0.89) (P < 0.05), and 0.59 (0.40-0.89) (P < 0.05), respectively; each 100 g increase of daily milk intake was associated with 11% lower risk of CVD incidence (HR, 0.89; 95% CI: 0.85-0.94; P < 0.001), and 11% lower risk of CVD mortality (HR, 0.89; 95% CI: 0.82-0.97; P = 0.008) after adjustment for age, sex, residential area, geographic region, education level, family history of CVD, smoking, alcohol drinking, physical activity level, body mass index, and healthy diet status (ideal or not). RCS analyses also showed a linear dose-response relationship with CVD (P for overall significance of the curve <0.001; P for non-linearity = 0.979; P for linearity <0.001) and stroke (P for overall significance of the curve = 0.010; P for non-linearity = 0.998; P for linearity = 0.002) incidence, and CVD mortality (P for overall significance of the curve = 0.045; P for non-linearity = 0.768; P for linearity = 0.014) within the current range of daily milk intake. CONCLUSIONS: Daily milk intake was associated with lower risk of CVD incidence and mortality in a linear inverse relationship. The findings provide new evidence for dietary recommendations in CVD prevention among Chinese adults and people with similar dietary pattern in other countries.

Beneficial effects of moderate to vigorous physical activity on cardiovascular disease among Chinese adults.

BACKGROUND: In China, lack of evidence remains a significant challenge for the national initiative to promote physical activity (PA). We aimed to quantify the beneficial effects of meeting or maintaining the recommended PA level [150 minutes per week (min/wk) of moderate PA or 75 min/wk of vigorous PA or an equivalent combination] on incident cardiovascular disease (CVD) among Chinese population. METHODS: We included 100,560 participants without history of CVD from three cohorts in the Prediction for Atherosclerotic Cardiovascular Disease Risk in China (China-PAR) project. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for CVD events and its subtypes, including stroke, coronary heart disease, heart failure, and CVD death. RESULTS: During a median follow-up of 7.3 years (range: 6-15 years), 777,163 person-years and 4693 incident CVD events were observed. Compared with participants who were inactive at baseline, the multivariable adjusted HR (95% CI) of developing CVD was 0.74 (0.69-0.79) for those who met recommended moderate to vigorous physical activity (MVPA) level at baseline. Furthermore, the risk of CVD incidence was reduced with increment of MVPA (P trend < 0.001), and the HR (95% CI) of highly-active versus inactive category was 0.62 (0.56-0.68). Compared with individuals who were inactive both at the baseline and follow-up, those keeping active over the period of follow-up had a substantial lower risk of incident CVD with the HR (95% CI) of 0.57 (0.43-0.77). CONCLUSIONS: The findings demonstrated that meeting and maintaining the recommended MVPA level could reduce the cardiovascular risk. Wider adoption of the PA recommendations would have considerable health impacts to the Chinese population.

Fasting glucose and its association with 20-year all-cause and cause-specific mortality in Chinese general population.

OBJECTIVE: The aim of this study was to explore the relationship between fasting glucose levels and all-cause and cause-specific mortality in Chinese population. METHODS: The role of fasting blood glucose levels as a predictor of all-cause and cause-specific mortality was estimated in 9930 participants from four Chinese general populations with a 20-year follow-up. Multivariate Cox proportional hazard models were used to identify the relationship between fasting glucose and mortality. RESULTS: There were 1471 deaths after a median follow-up of 20.2 years (a total of 187,374 person-years), including 310 cardiovascular deaths, 581 cancer deaths, and 580 other-cause deaths. After adjustment for age, sex, urban or rural, northern or southern of China, types of work, education level, physical exercise, smoking status, drinking status, body mass index, systolic blood pressure, and serum total cholesterol at baseline, the hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause mortality in the fasting blood glucose categories of <60, 60-69, 70-79, 90-99, 100-109, 110-125, and ≥126 mg/dl were 1.38 (1.04-1.84), 1.20 (1.01-1.43), 1.18 (1.03-1.36), 1.18 (0.99-1.41), 1.48 (1.16-1.88), 1.17 (0.84-1.62), and 2.23 (1.72-2.90), respectively, in contrast to the reference group (80-89 mg/dl). The HRs and 95% CIs for cardiovascular disease mortality in these groups were 2.58 (1.44-4.61), 1.41 (0.95-2.10), 1.56 (1.15-2.11), 1.29 (0.88-1.89), 1.36 (0.78-2.37), 1.05 (0.52-2.11), and 2.73 (1.64-4.56), respectively. CONCLUSIONS: Both low and high fasting glucose were significantly associated with increased risk of all-cause and cardiovascular mortality in Chinese general population.

Validation of spot urine in predicting 24-h sodium excretion at the individual level.

Background: Evidence for the effect of dietary sodium intake on the risk of cardiovascular disease has been controversial. One of the main explanations for the conflicting results lies in the great variability associated with measurement methods for sodium intake. Spot urine collection is a convenient method commonly used for sodium estimation, but its validity for predicting 24-h urinary sodium excretion at the individual level has not been well evaluated among the general population.Objective: The aim of this study was to evaluate the validity of the Kawasaki, the International Cooperative Study on Salt, Other Factors, and Blood Pressure (INTERSALT), and the Tanaka formulas in predicting 24-h urinary sodium excretion by using spot urine samples in Chinese adults.Design: We analyzed the relative and absolute differences and misclassification at the individual level from 3 commonly used methods for estimating sodium intake among 141 Chinese community residents.Results: The mean measured 24-h sodium excretion was 220.8 mmol/d. The median (95% CIs) differences between measured sodium and those estimated from the Kawasaki, INTERSALT, and Tanaka methods were 6.4 mmol/d (-17.5, 36.8 mmol/d), -67.3 mmol/d (-96.5, -46.9 mmol/d), and -42.9 mmol/d (-59.1, -24.8 mmol/d), respectively. The proportions of relative differences >40% with the Kawasaki, INTERSALT, and Tanaka methods were 31.2%, 41.1%, and 22.0%, respectively; and the absolute difference for the 3 methods was >51.3 mmol/d (3 g salt) in approximately half of the participants. The misclassification rate was 63.1% for the Kawasaki method, 78.7% for the INTERSALT method, and 66.0% for the Tanaka method at the individual level.Conclusion: The results from our study do not support the use of spot urine to estimate 24-h urinary sodium excretion at the individual level because of its poor performance with respect to misclassification. This trial was registered at www.chictr.org.cn as ChiCTR-IOR-16010278.

Risk stratification of atherosclerotic cardiovascular disease in Chinese adults.

OBJECTIVE: This study aims to determine the distribution of observed atherosclerotic cardiovascular disease (ASCVD) incidence in contemporary cohorts in China, and to identify cut-off points for ASCVD risk classification based on traditional criteria and new equations developed by Prediction for ASCVD Risk in China (China-PAR). METHODS: The study populations included cohorts in the China-PAR project, with 34,757 participants eligible for the current analysis. Traditional risk stratification was assessed by using Chinese guidelines on prevention of CVD and hypertension, and 5 risk groups were classified based on these guidelines after slight modification for available risk factors. Kaplan-Meier analysis was conducted to obtain the cumulative incidence of observed ASCVD events for all subjects and sub-groups. The predicted 10-year ASCVD risk was obtained using the China-PAR equations. RESULTS: A total of 1922 ASCVD events were identified during an average follow-up of 14.1 years. According to the group classification based on traditional risk stratification, the observed 10-year risks for ASCVD were 4.61% (95% confidence interval [CI]: 4.11-5.10%) in the moderate-risk group and 8.74% (95% CI: 7.82-9.66%) in the high-risk group. Based on the China-PAR equations for risk assessment of ASCVD, those with predicted risks of <5%, 5-10%, and ≥10% could be classified into categories of low-, moderate-, and high-risk for ASCVD, respectively. CONCLUSION: The findings enable development of a simple method for classification of individuals into low-, moderate-, and high-risk groups, based on the China-PAR equations. The method will be useful for self-management and prevention of ASCVD in Chinese adults.

Effects of salt substitutes on blood pressure: a meta-analysis of randomized controlled trials.

BACKGROUND: Clinical trials assessing the effects of salt substitutes on blood pressure (BP) have reported mixed results. OBJECTIVES: A meta-analysis of randomized controlled trials was conducted to evaluate the effect of salt substitutes on BP, including systolic BP (SBP) and diastolic BP (DBP). DESIGN: Studies were identified via systematic searches of the PubMed, Embase, Cochrane Library, Wanfang Data, and the China National Knowledge Infrastructure databases through December 2013. Random-effects models were used to estimate pooled mean differences in SBP and DBP. RESULTS: Six cohorts from 5 articles (1 trial enrolled 2 cohorts for independent intervention) consisting of 1974 participants were included. Pooled results showed that salt substitutes had a significant effect on SBP (mean difference: -4.9 mm Hg; 95% CI: -7.3, -2.5 mm Hg; P < 0.001) and DBP (mean difference: -1.5 mm Hg; 95% CI: -2.7, -0.3 mm Hg; P = 0.013). Significant heterogeneity was found for both SBP (I(2) = 76.7%) and DBP (I(2) = 65.8%). The sensitivity analysis indicated that the pooled effects of salt substitutes on SBP and DBP were robust to systematically dropping each trial. Furthermore, no evidence of significant publication bias from funnel plots or Egger's tests (P = 0.17 and 0.22 for SBP and DBP, respectively) was found. CONCLUSION: This meta-analysis showed that salt-substitution strategies are effective at lowering SBP and DBP, which supports a nutritional approach to preventing hypertension.

[Relationship of genetic variants and cardiovascular risk factors with interleukin-6 and interleukin-10 secreted by monocytes].

OBJECTIVE: To examine the relationship of interleukin (IL)-6 and IL-10 genetic variants and cardiovascular factors [oxygenized low density lipoprotein (ox-LDL), lower physical activity, overweight, etc.] with IL-6 and IL-10 secreted by monocytes. METHODS: In the study, 40 health persons, aged from 51 to 80 years, without stroke and myocardial infarction, were randomly sampled from a community-based population in Beijing in 2010. Their data on smoking, drinking, blood pressure, fasting glucose, and lipid were collected. The single nucleotide polymorphisms (SNPs) of IL-6 (rs1800796, rs1524107, rs2066992) and IL-10 (rs1800872, rs1554286, rs3021094) were genotyped. The human monocytes were cultivated in RPMI 1640 medium for 24 h; then divided into two equal parts, in which ox-LDL (50 mg/L) and phosphate buffer solution (PBS) were added for another 48 h. Finally, the secretions of IL-6 and IL-10 in the culture supernatants were measured with ELISA. RESULTS: Paired Wilcoxon tests showed that the IL-6, IL-10, and IL-6/IL-10 were significantly higher in ox-LDL medium than in PBS one (all P < 0.01). The concentrations in PBS/ox-LDL taken as repeated measurements, and adjusted for age and gender, the repeated general linear models showed: IL-10 was significantly lower for those overweight (BMI ≥ 26 kg/m(2)) than for those normal weight (P = 0.007), and IL-6/IL-10 was significantly higher in those overweight (P = 0.003). The IL-6/IL-10 was significantly higher in those with lower physical activity [metabolic equivalent of energy, METS < 166 kJ/(kg.d)] than those with higher physical activities (P = 0.046). IL-6 and IL-10 were significantly higher in alcohol drinkers (P = 0.049 and P = 0.006). IL-6 was significantly higher in those with higher high-density lipoprotein-cholesterol (HDL-c, ≥ 56.4 mg/dL, P = 0.027). There were significant interactions between IL-10 SNPs and ox-LDL on IL-10 (all P < 0.05), but no significant interactions between IL-6 gene SNPs and ox-LDL on IL-6. CONCLUSION: The ox-LDL together with lower physical activity and overweight shifts the balance of pro-inflammatory and anti-inflammatory in the direction of pro-inflammatory. The interaction between IL-10 gene and ox-LDL is intensively correlated with the secretion of the anti-inflammatory cytokine IL-10.

Metabolic syndrome and coronary artery calcification: a community-based natural population study.

BACKGROUND: Little is known about the influence of metabolic syndrome (MetS) on coronary artery calcification (CAC) in China. In this article, we aimed to explore the distribution of CAC in populations with and without MetS, and estimate the influence of MetS and its components on CAC in a community-based population of Beijing. METHODS: A total of 1647 local residents of Beijing, age 40-77 years, were recruited for a cardiovascular risk factors survey and were determined fasting plasma glucose (FPG), blood lipids, and 64 multi-detector computed tomography (64-MDCT) coronary artery calcium score (CACS) measurement (Agatston scoring). The distribution of CAC was described, and the influence of MetS components on CAC was evaluated. RESULTS: In this population, the prevalence and extent of CAC increased with increasing age and both were higher in MetS subjects compared to nonMetS subjects (all P < 0.05), with the exception of those older than 65 years old. The risk of CAC increased with increasing numbers of MetS components, and the odds ratios for predicting positive CAC in subjects with 1, 2, 3, and = 4 MetS components were 1.60, 1.84, 2.12, and 3.12, respectively (all P < 0.05). Elevated blood pressure, elevated FPG, elevated triglycerides, and overweight increased the risk of CAC, yielding odds ratios of 2.64, 1.67, 1.32, and 1.37, respectively (all P < 0.05). CONCLUSIONS: In the Beijing community-based population, MetS increases the risk of CAC. The risk of CAC increases with increasing numbers of MetS components. Not only the number, but also the variety of risk factors for MetS is correlated with the risk of CAC. Elevated blood pressure, hyperglycemia, hypertriglyceridemia and overweight increase the risk of CAC.

[The optimal cut-off value of waist-to-height ratio for detecting severe central obesity and low body weight adult Chinese population].

OBJECTIVE: To explore the optimal cut-off values of waist-to-height ratio (WHtR) for detecting the severe central obesity and low body weight in adult Chinese population. METHODS: A total of 30 630 participants aged 35-59 years from different areas in mainland China were surveyed for cardiovascular diseases risk factors in two independent cross-sectional studies that carried out in 1992-1994 and 1998, respectively. Indices, such as sensitivity, specificity for hypertension, abnormal glucose, high serum total cholesterol, low serum high density lipoprotein cholesterol and clustering of risk factors (number ≥ 2) were calculated to evaluate the efficacy individual cut-off point of WHtR. The cut-off point value for obvious central obesity was fixed on the point whose specificity of the point was gathered more than 90%. And the cut-off point value to indicate low weight was determined by the percentile distribution of WHtR, at which the 5th percentile of point, both in male and female population. Based on the principle of convenient and practical for use, the optimal cut-off point values of WHtR for low weight and obvious central obesity were determined. RESULTS: The cut-off values of WHtR to detect severe central obesity were 0.54 and 0.57 for men and women, respectively. Additionally, the cut-off points of WHtR for each of the 4 cardiovascular risk factors to evaluate the severity separately ranged from 0.54 to 0.55 in male, and ranged from 0.57 to 0.58 in female. The 5th percentile of WHtR, which was the point value of WHtR to indicate low body weight, was 0.40 in both male and female population. CONCLUSION: Our data suggest that the optimal cut-off value of WHtR for defining severe central obesity and low body weight should be 0.57 and 0.40, respectively.

[Relation between uric acid and coronary artery calcification:a community-based cross-sectional survey among Beijing natural population].

OBJECTIVE: To investigate the influence of uric acid on coronary artery calcification in the natural population in Beijing. METHODS: From April to July 2012, 903 subjects from the natural population(aged 37-76 years for men, aged 42-76 years for women)in Xishan community, Beijing, were selected to accept a survey on the risk factors of cardiovascular. Blood tests and CT coronary artery calcium scans were carried out. RESULTS: At the 1 Quartile(1 Q), 2 to 3 Quartile(2-3 Q)and 4 Quartile(4 Q)of uric acid levels, the prevalence rates of coronary artery calcium were 37.2% , 45.5% , 60.6% (P<0.001) and the coronary artery calcium scores were (109.7±333.1)AU, (133.9±356.9)AU, (200.8±459.4) AU (P < 0.001)respectively. Data from the univariate logistic regression analysis showed that with the increase of uric acid, the prevalence rates of coronary artery calcium also increased(OR2-3Q = 1.41, 95% CI:1.02-1.95, P = 0.040; OR4Q = 2.60, 95% CI:1.78-3.80, P < 0.001). However, the relationship between uric acid and coronary artery calcium disappeared when using the multivariate logistic regression analysis(OR2-3Q = 0.92, 95% CI: 0.60-1.43, P = 0.713;OR4Q = 1.38, 95% CI:0.80-2.39, P = 0.247). CONCLUSION: Uric acid did not seem to be an independent risk factor for coronary artery calcium, although the prevalence and extent of coronary artery calcium increased along with the increasing trend of uric acid.

[Application of wavenumber-linear scaling to the calculated Raman frequencies of polyenes and carotenoids].

Raman spectra of two typical carotenoids (beta-carotene and lutein) and some short (n = 2-5) polyenes were calculated using density functional theory. The wavenumber-linear scaling (WLS) and other frequency scaling methods were used to calibrate the calculated frequencies. It was found that the most commonly used uniform scaling (UFS) method can only calibrate several individual frequencies perfectly, and the systematic result of this method is not very good. The fitting parameters obtained by the WLS method are upsilon(obs)/upsilon(calc)) = 0.999 9-0.000 027 4upsilon(calc) and upsilon(obs)/upsilon(calc)= 0.993 8-0.000 024 8upsilon(calc) for short polyenes and carotenoids, respectively. The calibration results of the WLS method are much better than the UFS method. This result suggests that the WLS method can be used for the frequency scaling of the molecules as large as carotenoids. The similar fitting parameters for short polyenes and carotenoids indicate that the fitting parameters obtained by WLS for short polyenes can be used for calibrating the calculated vibrational frequencies of carotenoids. This presents a new frequency scaling method for vibrational spectroscopic analysis of carotenoids.

[Relationship between physical activity and the incidence of metabolic syndrome in Chinese adults: a prospective cohort study].

OBJECTIVE: To investigate the association between physical activity (PA) and the incidence of metabolic syndrome (MS) in Chinese adults. METHODS: Data on PA and other variables were obtained at the baseline examination of China Multi-center study of Cardiovascular Epidemiology in 1998 and of International Collaborative study of Cardiovascular Disease in Asia(InterASIA) during 2000 - 2001. Follow-up study was conducted in 2007 - 2008. A total of 11 512 Chinese adults aged 35 - 74 years (5563 men and 5949 women) were included in the final data analysis. Information on demographics, PA, smoking and alcohol consumption were obtained and components of MS were examined. Participants were divided into four groups according to quartile of total metabolic equivalent (MET) values per day. In addition, subjects were grouped into the following categories according to occupational PA: inactive, light, moderate and vigorous. Binary logistic model was used to examine the association between PA and the incidence of MS. RESULTS: A total of 2527 cases with MS were documented during an average following up of 8.1 years. The annual incidence rate of MS was 2.71% (2527/93 178.68). After multivariate logistic regression analysis, compared with participants with total PA volume < 32.0 MET×h×d(-1) (annual incidence rate was 3.19% (697/21 830.74)), the RR (95%CI) value of participants with total PA volume during 32.00 - 37.85, 37.86 - 52.29, and ≥ 52.30 MET×h×d(-1) was 1.05(0.92 - 1.19), 0.98(0.86 - 1.12), and 0.68(0.59 - 0.80), respectively (χ(2)trend = 34.23, P < 0.05), with corresponding annual incidence rates of 2.82% (690/24 504.25), 2.73% (661/24 179.36) and 2.11% (479/22 664.33). In addition, compared to inactive occupational PA (annual incidence rate was 2.76% (402/14 588.33)), the corresponding RR (95%CI) value was 0.80 (0.69 - 0.92), 0.70 (0.59 - 0.82), and 0.54 (0.45 - 0.65) (χ(2)trend = 42.34, P < 0.05), and the annual incidence rates were 2.86% (648/22 663.41), 2.40% (455/18 956.14) and 1.89% (344/18 173.86) in participants with light, moderate and vigorous occupational PA, respectively. CONCLUSION: Both increased total PA volume and occupational PA intensity are significantly associated with decreased risk of incidence of MS.

[Contrast and efficacy of waist circumference and waist-to-height ratio in predicting central obesity].

OBJECTIVE: To study the efficacy of waist circumference (WC) and waist-to-height ratio (WHtR) in predicting central obesity among the Chinese adult population. METHODS: A total of 30 630 participants aged 35 - 59 from different areas in mainland China were surveyed for the risk factors of cardiovascular diseases (CVD) in two independent cross-sectional studies that were carried out in 1992 - 1994 and 1998, respectively. In subgroups with different heights, consistency analysis for central obesity diagnosed by WHtR (≥ 0.50) and WC (≥ 85 cm for men, ≥ 80 cm for women) were conducted. Sensitivity and specificity for predicting the clustering of risk factors (number ≥ 2) would include hypertension, abnormal glucose, high serum total cholesterol and low serum high density lipoprotein cholesterol and they were also calculated to evaluate the efficacy of prediction, with the two indices in the different height subgroups as well. RESULTS: The consistency of diagnosis on central obesity by WC and WHtR was good in the whole population (the Kappa value was 0.805 in men and 0.816 in women), but poor (all Kappa values ≤ 0.6) for those with tall (men's height ≥ 180 cm and women's height ≥ 170 cm) or with short statures (men's height < 160 cm, and women's height < 150 cm). Sensitivity in the shorty subgroups and specificity in the tall subgroups appeared poor in both genders, by using WC criteria to predict the clustering of risk factors. However, the sensitivity (ranged from 56.1% to 64.1% for men and 64.7% to 73.2% for women) and specificity (from 70.0% to 74.5% for men, 59.2% to 75.9% for women) seemed good and stable in all the subgroups as well as in both genders by using the WHtR criteria. CONCLUSION: WC and WHtR could both be applied in predicting the clustering of risk factors of CVD and in evaluating the central obesity in the whole population. With satisfactory efficacy, WHtR seemed to be better than WC in the prediction of central obesity, both in men or women with tall or short statures.

Intersubband absorption properties of high Al content AlxGa1-xN/GaN multiple quantum wells grown with different interlayers by metal organic chemical vapor deposition.

High Al content AlxGa1-xN/GaN multiple quantum well (MQW) films with different interlayers were grown by metal organic chemical vapor deposition. These MQWs were designed to achieve intersubband (ISB) absorption in the mid-infrared spectral range. We have considered two growth conditions, with AlGaN interlayer and GaN/AlN superlattice (SL) interlayer, both deposited on GaN-on-sapphire templates. Atomic force microscopy images show a relatively rough surface with atomic-step terraces and surface depression, mainly dominated by dislocations. High-resolution X-ray diffraction and transmission electron microscopy analyses indicate that good crystalline quality of the AlGaN/GaN MQW layer could be achieved when the AlGaN interlayer is inserted. The ISB absorption with a peak at 3.7 µm was demonstrated in MQW films with AlGaN interlayer. However, we have not observed the infrared absorption in MQW films with GaN/AlN SL interlayer. It is believed that the high dislocation density and weaker polarization that resulted from the rough interface are determinant factors of vanished ISB absorption for MQW films with the GaN/AlN SL interlayer.

Subclinical atherosclerosis in northern and southern China: the Chinese paradox.

BACKGROUND: The incidence of coronary heart disease (CHD) is higher in Northern than that in Southern China, however differences in traditional CHD risk factors do not fully explain this. No study has examined the differences in subclinical atherosclerosis that may help explain the differences in incidence. This study examined these differences in subclinical atherosclerosis using coronary computed tomography (CT) for calcification between the Northern and Southern China. METHODS: We selected a random sample of participants in a large multi-center ongoing epidemiologic study for coronary calcium scanning in one northern city (North) (Beijing, n = 49) and in two southern cities (South) (Shanghai, n = 50, and Guangzhou, n = 50). Participants from the three field centers (mean age 67 years) underwent coronary risk factor evaluation and cardiac CT scanning for coronary calcium measurement using the Multi-Ethnic Study of Atherosclerosis scanning protocol. RESULTS: Adjusted log-transformed coronary artery calcium score in North China (Beijing) was 3.1 ± 0.4 and in South China (Shanghai and Guangzhou) was 2.2 ± 0.3 (P = 0.04). Mean calcium score for the northern city of Beijing was three times higher than that of the southern city of Guangzhou (P = 0.01) and 2.5 times higher than for the southern city of Shanghai (P = 0.03). CONCLUSIONS: The extent of subclinical atherosclerosis is significantly higher in the northern city of Beijing than that in the two southern cities of Guangzhou and Shanghai, even after adjusting for standard cardiac risk factors. This finding suggests that standard risk factors do not fully explain north south differences in clinical CHD incidence.

[Hypertension and peripheral arterial diseases].

OBJECTIVE: To explore the relationship between different blood pressure levels and peripheral arterial disease (PAD) assessed by ankle-brachial index (ABI). METHODS: Data including ABI,blood pressure, health history, medication use, blood biochemistry and physical examinations derived from 15 817 subjects from 9 areas throughout China were analyzed. Univariate and multivariate adjusted Logistic regression analyses were used for the data analyses. RESULTS: Blood pressure levels were classified into 5 levels as normal blood pressure, high normal blood pressure, primary hypertension, secondary hypertension and the third grade of hypertension. With the increasing of blood pressure levels, the risk of PAD gradually increased (Ptrend<0.05). In comparison with normal blood pressure group, the ORs of PAD for the other groups were 1.10 (95%CI: 0.93-1.29), 1.17 (95% CI: 0.97-1.40), 1.91 (95% CI: 1.55-2.37), and 2.64 (95% CI: 1.99-3.49), respectively. After adjusting for gender(only for total population), age, urban/rural, smoke, obesity/overweight, the history of hypercholesterolemia and diabetes, the ORs were 1.11 (95%CI: 0.94-1.32), 1.13 (95% CI: 0.93-1.38), 1.85(95% CI: 1.47-2.33), and 2.66 (95% CI: 1.98-3.57) (Ptrend<0.05). CONCLUSION: PAD risk increases in proportion with the increasing blood pressure level.

[The relationship between occupational physical activity intensity and peripheral arterial disease].

OBJECTIVE: to explore the relationship between occupational physical activity and peripheral arterial disease (PAD)assessed by ankle-brachial index (ABI). METHODS: data including ABI, occupational physical activity intensity, health history, medication use, blood biochemistry and physical examinations derived from 16 446 subjects from 9 areas throughout China were analyzed. Univariate and multivariate adjusted logistic regression analysis were used for the data analyses. RESULTS: occupational physical activity intensity was classified into 5 levels as jobless, very light, light, moderate and heavy intensity. With the increasing of physical activity intensity, the risk of PAD gradually decreased (P(trend) < 0.05). In comparison with jobless group, the ORs of PAD for other groups were 0.65 (95%CI: 0.52, 0.82), 0.70 (95%CI: 0.56, 0.87), 0.57 (95%CI: 0.44, 0.73), 0.65 (95%CI: 0.53, 0.80) respectively. After adjusting for gender, age, smoke, obesity/overweight, the history of hypertension, hypercholesterolemia, diabetes, cardiovascular disease and stroke, the ORs were 1.02 (95%CI: 0.80, 1.31), 0.91 (95%CI: 0.72, 1.15), 0.92 (95%CI: 0.70, 1.19), 0.90 (95%CI: 0.72, 1.12) (P(trend) < 0.05). CONCLUSION: PAD risk reduced in proportion with increasing occupational physical activity.

[A community-based study on relations between metabolic syndrome and carotid atherosclerosis in a middle-aged population].

OBJECTIVE: To explore the association between metabolic syndromes (MS) and carotid atherosclerosis and to estimate the predictive effects of MS under 3 different definitions. METHODS: A cross-sectional study was conducted in 2 community-based populations in Beijing, in 2008. 1266 subjects (598 men, 668 women), aged 45 - 69, were included in the analyses. MS was defined by the criteria of International Diabetes Federation (IDF), the revised NCEP ATP III (ATPIII-R) and "The Guidelines of Dyslipidemia Control for Chinese Adult" ("Guidelines") in 2007. RESULTS: The prevalence rates of MS by the 3 criteria were 39.0%, 43.3% and 30.9% respectively. The Kappa value for the measure of the agreement between each pair of the 3 definitions were 0.911, 0.719 and 0.730 respectively. The intima-media thickness in common carotid artery (CCA-IMT) was significantly higher (P < 0.001) in all MS groups than in non-MS groups, diagnosed with the 3 criteria independent of age, gender, LDL-C, and current smoking status. After adjustment of age, gender, LDL-C, and current smoking status, the classification of MS significantly increased the risk of prevalence of carotid atherosclerotic plaques, compared to the non-MS group. OR value were 1.499 (95%CI: 1.157 - 1.942) for IDF, 1.696 (95%CI: 1.314 - 2.189) for NCEP-R, 1.763 (95%CI: 1.344 - 2.312) for "Guideline" respectively. CONCLUSION: Our research findings indicated that, when MS were defined with the 3 definitions, prediction on the risk of sub-clinical atherosclerosis would work beyond some of the conventional cardiovascular risk factors such as smoking, LDL-C. There might exist some differences in gender issue on the strength of association between MS when diagnosed by different criteria and carotid plaque.