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Few studies have investigated the prevalence of myopia in Northwest China. This cross-sectional study aimed to investigate the prevalence and associated factors of myopia and high myopia in adults aged 40–80 years in the Han and Yugur populations living in Gansu Province, Northwest China. A total of 3,845 participants were included. The overall age- and sex-adjusted prevalence of myopia (spherical equivalent (SE) + 0.5 D) were 16.4%, 0.7% and 26.2% in Yugur participants, respectively, and 34.3%, 5.0% and 19.2% in Han participants, respectively. The prevalence of myopia and high myopia in Han participants was significantly higher than that in Yugur participants (both P

Background The independent association of neck circumference (NC) on elevated blood pressure is still uncertain in adults of China. The aim of this study is to explore such association and investigate the predictive value of NC on hypertension. Methods A total of 4279 adults aged 20–80 years participated in the cross-sectional study in 2014. Anthropometric information, NC, body composition indexes such as waist circumference, hip circumference and body fat percentage, and blood pressure were measured. General linear regression model was used to explore the association between NC and blood pressure; Logistic regression models were fitted to calculate the multi-variable adjusted prevalence, and the association of NC with hypertension. Results The overall prevalence of hypertension and pre-hypertension were 11.05 and 23.63%, respectively. NC was positively associated with both SBP and DBP (p p for trend Conclusions NC was associated with both pre-HTN and HTN independent from other body composition indexes. NC is a simple and useful anthropometric index to identify elevated blood pressure in Chinese adults.

Background Our study aimed to explore the prevalence and risk factors of refractive error (RE) in Han and Tibetan population aged 50–79 years in Xining and surrounding areas in Qinghai Province on Qinghai-Tibet Plateau. Methods As part of the China National Health Survey, our cross-sectional study compared the age-adjusted prevalence of RE in Han and Tibetan older adults aged 50–79 years in Xining and surrounding areas. A multivariate logistic regression model was used to identify risk factors for myopia and hyperopia. Results Among 769 Han participants and 476 Tibetan participants, the age-adjusted prevalence of myopia (spherical equivalent (SE) + 0.5D), high myopia (SE = 0.5D) is 28.56, 22.82, 2.80, and 69.38%. Han participants have higher age-adjusted prevalence of myopia (32.93% vs 21.64%, p p = 0.001) and astigmatism (72.14% vs 64.94%, p = 0.021) compared to Tibetan participants. Being Tibetan is the protective factor of myopia compared to being Han (OR 0.58, 95%CI 0.42–0.79, p p = 0.032), longer time length in rural area (p = 0.048), undergraduate/graduate education level (p = 0.031), lighter active level (p = 0.007) and lower BMI (p = 0.015) are risk factors for myopia. Older age (all p p = 0.013) also increase the hyperopia risk. Conclusions Our study found an overall prevalence of myopia of 28.56% in Xining and surrounding areas in adults older than 50 years. Han population has higher myopia risk than Tibetan population. More medical and social resources should be allocated to improve the vision and life quality of older adults.

Introduction The prevalence of hyperuricemia is increasing world widely; the understanding of population attributable faction of modifiable risk factors is important for disease prevention. Given the sparse evidence on how modifiable risk factors influence hyperuricemia in mainland China, we aim to explore the effect of excess weight and alcohol consumption and the population attributable fractions of hyperuricemia based on a national survey in mainland China. Methods Using data from China National Health Survey which included 31746 Han Chinese aged 20-80 from ten provinces, we estimated the prevalence and modifiable risk factors (overweight/obesity and alcohol consumption)of hyperuricemia. Hyperuricemia was defined as serum uric acid > 417 μmol/L in men and > 340 μmol/L in women. Restricted cubic spline models were used to demonstrate the linear and non-linear association between exposures and hyperuricemia. The adjusted population attributable risk (PAR) was calculated to understand the relative importance of each modifiable risk factor. Results The prevalence of hyperuricemia was 25.1% in men and 15.9% in women. The population fraction of hyperuricemia cases that could be avoided by weight loss was 20.6% (19.2% to 22.0%) in men and 18.1% (17.1% to 19.0%) in women. The PAR of alcohol consumption was 12.8% (8.5% to 17.1%) in men. Participants from southwest China had the highest hyperuricemia prevalence (47.9% in men and 29.9% in women), but with lower PAR of modifiable risk factors, especially in men (16.7%). Subjects in North China had lower hyperuricemia prevalence but higher PAR of modifiable risk factors. 44.8% male hyperuricemia cases in Inner Mongolia (26.9% of hyperuricemia prevalence) and 37.7% cases in men from Heilongjiang (34.4% of hyperuricemia prevalence) were attributable to overweight/obesity and alcohol consumption. Conclusion There are significant sex and geographic difference on population attributable risk of hyperuricemia due to modifiable risk factors. More tailored prevention strategies are needed to prevent hyperuricemia through weight loss and the reduction of alcohol consumption.

Introduction: Serum uric acid (SUA) has been found correlated with an increased risk of hypertension, but evidence is sparse regarding the association in Gansu Province, especially in Yugur people. This study aimed to explore the nonlinear relationship between SUA levels and hypertension in Han and Yugur people in China. Methods: The cross-sectional study samples (n = 5,327) were from the China National Health Survey (CNHS) in Gansu Province. Participants were selected using a multistage stratified cluster sampling method. SUA was measured by enzymatic methods. The restricted cubic spline regression was performed to evaluate the shape of the association. Results: The overall prevalence of hypertension and hyperuricemia was 28.4% and 17.0%, respectively, in this study. Comparing the highest (>416.4 μmol/L) to the lowest (Conclusions: SUA was significantly and independently associated with an increased risk of hypertension in Han and Yugur people. Prospective studies are needed to confirm these findings.

Background：The association between long-term air pollutants exposure with blood pressure and hypertension defined by 2017 American College of Cardiology (ACC)/American Heart Association (AHA) Hypertension Guideline is still conflicting. This study was designed to investigate the associations between long-term exposure to air pollutants, blood pressure and hypertension defined by Chinese and ACC/AHA guideline in Chinese adults. Methods: Our study was based on the baseline survey of the Cohort Study on Chronic Disease of Communities Natural Population in Beijing, Tianjin and Hebei (CHCN-BTH) from 2017 to 2019. A spatial statistical model was used to assessed three-year (2014-2016) average pollutant concentrations for PM2.5, and other pollutants concentration (PM10, SO2, NO2) was assessed by data of air monitoring stations. Results: A total of 32,135 adults aged 18-80 years were included, each interquartile range (IQR) increment of PM2.5, PM10, SO2 and NO2 was associated with increases of 0.66mmHg (95%CI: 0.29, 1.03), 040mmHg (0.00, 0.81), 1.38mmHg (0.92, 1.84) and 0.54mmHg (0.16, 0.91) in SBP, respectively. SO2 was associated with increases 0.42mmHg (0.11, 0.72) in DBP. PM2.5, PM10, SO2 and NO2 was associated with an 14% (Odds ratio [OR]:1.14, 95%CI:1.06-1.23), 6% (1.06, 1.00-1.13), 9% (1.09, 1.02-1.17) and 8% (1.08, 1.01-1.16) increase of hypertension defined by Chinese guideline. PM2.5 and SO2 was associated with 16% (1.166, 1.093-1.245) and 10% (1.10, 1.03-1.18) increase of hypertension defined by ACC/AHA guideline. Two-pollutants model, traffic-related pollution model and stratified analysis yielded similar results. Conclusions: We found that long-term exposure to PM2.5, NO2 and SO2 is associated with increase of blood pressure and hypertension defined by both Chinses and ACC/AHA guideline. PM10 is associated with higher SBP and risk of hypertension defined by Chinese guideline.

BACKGROUND: Evidence on how different body composition indexes, such as body mass index (BMI), fat mass index (FMI) and fat free mass index (FFMI), influence blood pressure (BP) in Chinese children and adolescents is sparse. The aim of this study is to assess the effect of different body composition on BP in participants aged 7–18 in south China. METHODS: A cross-sectional study was conducted in 2013. A total of 1,609 children and adolescents from urban and rural areas in Hainan Province, South China, were selected using multi-stage stratified cluster sampling method. Each participant underwent anthropometric and BP tests. BMI, FMI and FFMI were calculated and analyzed as body composition indexes. RESULTS: In the population level stratified by sex, FFMI had the highest r-value (Partial Spearman correlations) of correlation with systolic BP in boys (r(s)=0.305, P

BACKGROUND: To evaluate the contributions of elevated lipoprotein(a) [Lp(a)] to the risk of coronary heart disease (CHD) in the general Chinese community population according to different lipid profiles. METHODS: We recruited individuals aged over 18 years from the baseline survey of the Cohort Study on Chronic Disease of Communities Natural Population in Beijing, Tianjin and Hebei (CHCN-BTH) using a stratified, multistage cluster sampling method. Data were collected through questionnaire surveys, anthropometric measures and laboratory tests. Restricted cubic spline (RCS) functions, multivariate logistic regression, sensitivity analyses and stratified analyses were used to evaluate the association between Lp(a) and CHD. RESULTS: A total of 25,343 participants were included, with 1,364 (5.38%) identified as having CHD. Elevated Lp(a) levels were linearly related to an increased risk of CHD (P(overall-association)95th percentiles were 1.07 (0.93, 1.23), 1.26 (1.07, 1.50) and 1.68 (1.30, 2.17), respectively (P for trend

Background Evidence regarding the effects of ambient air pollution on new stage 1 hypertension defined by the 2017 ACC/AHA Hypertension Guideline remains sparse. Objectives To investigate the association of long-term exposure to ambient PM2.5 with stage 1 hypertension and to explore the mediating and modifying effects of PM2.5 on cardiovascular disease (CVD). Methods A total of 32,135 participants aged 18–80 years were recruited in 2017. The three-year (2014–2016) average PM2.5 concentrations were assessed by a spatial statistical model. Blood pressure (BP) was divided into four categories according to the 2017 ACC/AHA Hypertension Guideline: normal BP (SBP Results We detected a positive significant association between long-term exposure to PM2.5 and stage 1 hypertension. Compared to normal BP, the OR was 1.05 (95% CI: 1.02, 1.08) per 10 μg/m3 increase in PM2.5. The association was stronger than that of elevated BP but weaker than that of stage 2 hypertension. Stage 1 hypertension only partially mediated the association between PM2.5 and CVD, and the mediation proportions ranged from 1.55% to 11.00%. However, it modified the association between PM2.5 and CVD, which was greater in participants with stage 1 hypertension (OR: 1.66; 95% CI: 1.43, 1.93) than in participants with normal BP (OR: 1.32; 95% CI: 1.11, 1.57), with P interaction Conclusions Long-term exposure to ambient PM2.5 was significantly associated with stage 1 hypertension. This earlier stage of hypertension may be a trigger BP range for adverse effects of air pollution in the development of hypertension and CVD, especially in young and middle-aged individuals.

This study aims to investigate the association between socioeconomic status and overweight/obesity in rural-to-urban Yi migrants in China, and to explore whether the association varied by the age at arriving urban areas. The cross-sectional population-based data from the Yi Migrants Study in 2015 was used, which included 1,181 Yi migrants aged 20–80 years. Socioeconomic status was evaluated by education level, personal annual income, and a composited variable (socioeconomic status index, SESI). Measured weight and height were used to calculate BMI and to define overweight/obesity (BMI ≥ 24 kg/m2). The results suggested that the association of income and SESI with overweight/obesity was not significant when age at arrival (two groups

Background Large-scale epidemiological surveys focusing on characteristic differences in psychological and physical health conditions in Chinese adults are lacking. Objective To investigate the association of noncommunicable chronic diseases (NCDs) with depression, anxiety and stress in the Chinese general population. Methods A total of 13784 participants were recruited from the baseline survey of the Cohort Study on Chronic Disease of Communities Natural Population in Beijing, Tianjin and Hebei (CHCN-BTH) from 2017 to 2019. Sociodemographic characteristics, lifestyle and NCDs were assessed via questionnaire. Stress, anxiety and depression were assessed by the Depression-Anxiety-Stress Scale (DASS-21). The relationship of NCDs with psychological symptoms was determined through logistic regression analysis. Results Multivariate logistic regression analysis revealed that the prevalence of stress (OR = 1.640; 95% CI: 1.381–1.949), anxiety (OR = 1.654; 95% CI: 1.490–1.837) and depression (OR = 1.460; 95% CI: 1.286–1.658) symptoms were all significantly higher in patients with NCDs. Multimorbidities were associated with a higher risk of stress (OR = 2.310; 95% CI: 1.820–2.931), anxiety (OR = 2.119; 95% CI: 1.844–2.436) and depression (OR = 2.785; 95% CI: 1.499–2.126) than single NCDs. A course of disease within 1 year or more than 5 years also was associated with a higher risk. Limitations The cross-sectional design could not examine the causal link between psychological symptoms and NCDs. Conclusion Psychological symptoms were more prevalent among individuals with NCDs in the Chinese general population. This study suggests that more attention should be paid to the mental health problems of patients with NCDs.

As part of the China National Health Survey, the objective of this study was to explore the prevalence, patterns, and influencing factors of smoking, and understand reasons for smoking cessation among adults in Hebei Province, central China. Using a multi-stage stratified cluster sampling method, 6,552 adults (2,594 males) aged 20–80 were selected in 2017. Demographic, socioeconomic, and tobacco use information were collected by questionnaire interview. The prevalence of ever-smoking, current smoking, and ex-smoking was 28.94, 21.08, and 7.86%, respectively. Male participants had a much higher prevalence of ever-smoking and current smoking (67.39 and 48.77%) than females (3.74 and 2.93%). In male participants, the daily cigarette consumption was 16.61, and the mean age of smoking initiation was 20.95, decreasing with birth year (27.50 in people born before 1946 vs. 17.9 for those born after 1985, p for trend < 0.001). Over 40% of male ever-smokers initiated regular smoking before 20. Compared with never drinking, the ORs (95% CI) of ever-smoking for low, moderate, and high alcohol consumption in male participants were 1.44 (1.11–1.86), 2.80 (1.91–4.11), and 2.40 (1.72–3.33), respectively. Among 479 male ex-smokers, 50.94% stopped smoking because of illness and 49.06% by choice. Among male ex-smokers, hypertensive men were more likely to quit smoking than the normotensive individuals (OR: 1.48, 95% CI: 1.13–1.96). For CVD patients, this effect was estimated as 2.27 (95% CI: 1.56–3.30). This study revealed a high prevalence of ever-smoking, especially in men, in a representative population in central China. Health education focus on tobacco control could be integrated with alcohol consumption reduction to achieve additional benefit.

The potential effect of long-term exposure to ambient air pollutants on low-grade systematic inflammation has seldom been evaluated taking indoor air pollution and self-protection behaviors on smog days into account. A total of 24,346 participants at baseline were included to conduct a cross-sectional study. The annual (2016) average pollutant concentrations were assessed by air monitoring stations for PM2.5, PM10, SO2, NO2, O3 and CO. Associations between annual ambient air pollution and low-grade systematic inflammation (hsCRP>3 mg/L) were estimated by generalized linear mixed models. Stratification analysis was also performed based on demographic characteristics, health-related behaviors and disease status. Annual ambient NO2 and O3 were all associated with low-grade systematic inflammation in single-pollutant models after adjusting for age, sex, blood lipids, blood pressure, lifestyle risk factors, cooking fuel, heating fuel and habits during smog days (NO2 per 10 μg/m3: OR = 1.057, P = 0.018; O3 per 10 μg/m3: OR = 0.953, P = 0.012). The 2-year and 3-year ozone concentrations were consistently associated with lower systematic inflammation (2-year O3 per 10 μg/m3: OR = 0.959, P = 0.004; 3-year O3 per 10 μg/m3: OR = 0.961, P = 0.014). In two-pollutant models, the estimated effects of annual NO2 and O3 on low-grade systematic inflammation remained stable. The effect size of annual pollutants on inflammation increased in participants without air-purifier usage (NO2 per 10 μg/m3: OR = 1.079, P = 0.009; O3 per 10 μg/m3: OR = 0.925, P = 0.001), while the association was null in the air-purifier usage group. Thus, long-term exposure to ambient NO2 and O3 was associated with low-grade systemic inflammation, and the results were generally stable after sensitivity analysis. The usage of air purifiers on smog days can modify the association between gaseous pollutants and systematic inflammation.

Background: This study aimed to assess the prevalence of childhood pre-hypertension and hypertension (elevated blood pressure, EBP) and explore their risk factors, especially the role of body composition and serum total calcium on EBP. Methods: From Nov 2013 to Jul 2014, a cross-sectional study was conducted in Hainan and Shaanxi Provinces in China. Two thousand two hundred eighty-three children and adolescents aged 7–18 underwent anthropometric and blood pressure measurements. Fasting blood was collected and serum total calcium was tested. Blood pressure standards from the updated Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents were used to classify BP groups based on age, sex and stature. Results: The overall prevalence of pre-hypertension and hypertension were 8.36 and 7.06%, respectively. Boys, older age, living in Hainan Province, excess adiposity and higher level of serum total calcium were found to be associated with EBP. Lean subjects had an average 3.87 mmHg decrease in systolic blood pressure (SBP) than normal weight groups. In contrary, overweight/obesity had increased SBP (3.69 mmHg) and diastolic blood pressure (DBP) (2.58 mmHg) than the normal weight group. Participants with high-level serum total calcium had a 1.60 mmHg increased SBP and 1.77 mmHg increased DBP than the low-level group. Compared with normal weight individuals, lean subjects appeared to have decreased odds of EBP (OR = 0.65, 95% CI: 0.43–0.98) but overweight/obese individuals were more likely to have EBP (OR = 2.67, 95% CI: 1.68–4.25). High-level of serum total calcium was associated with increased odds of EBP, the OR (95% CI) was 1.51 (1.17–1.94). The restrict cubic spline presented a linear relationship between serum total calcium and OR of EBP (P < 0.001). Conclusions: Body composition and serum total calcium were positively associated with blood pressure in children and adolescents. Serum calcium could be considered as an untraditional risk factors for high blood pressure screening along with other body composition indexes in clinical settings.

Background The present study was the first one aimed to investigate the current muscle fitness and its associated factors among children and adolescents in mainland China. Methods From Nov 2013 to Jul 2014, 2283 children and adolescents aged 7–18 were recruited in Hainan and Shaanxi Provinces in China by cross-sectional design. Information on anthropometry and muscle fitness, measured by hand grip strength (GS), vertical jump (VJ) and sit-and-reach (SR), were collected. Analysis of covariance was performed by using general linear regression models to identify the association between BMI and muscle fitness. Results The means of GS, VJ and SR in boys were 22.30 ± 11.55 kg, 22.93 ± 6.80 cm and 3.58 ± 7.31 cm, respectively, and in girls were 16.61 ± 6.87 kg, 18.11 ± 4.08 cm and 7.18 ± 5.72 cm, respectively. GS (from 8.26 kg in the 7–8-year-old group to 27.91 kg in the 17–18 group) and SR (from 1.75 cm in the-8-year-old group to 10.12 cm in the 17–18 group) increased with age (both p for trend

Background Evidence regarding the effects of long-term and high-level ambient air pollution exposure on cardiac conduction systems remains sparse. Objectives To investigate the associations of long-term exposure to air pollution and cardiac conduction abnormalities in Chinese adults and explore the susceptibility characteristics. Methods In 2017, a total of 27,047 participants aged 18–80 years were recruited from the baseline survey of the Cohort Study on Chronic Disease of Communities Natural Population in Beijing, Tianjin and Hebei (CHCN-BTH). The three year (2014–2016) average pollutant concentrations were assessed by a spatial statistical model for PM2.5 and air monitoring stations for PM10, SO2, NO2, O3 and CO. Residential proximity to a roadway was calculated by neighborhood analysis. Associations were estimated by two-level generalized linear mixed models. Stratified analyses related to demographic characteristics, health behaviors, and cardiometabolic risk factors were performed. Two-pollutant models were used to evaluate the possible role of single pollutants. Results We detected significant associations of long-term air pollutant exposure with increased heart rate (HR), QRS and QTc, such that an interquartile range increase in PM2.5 was associated with 3.63% (95% CI: 3.07%, 4.19%), 1.21% (95% CI: 0.83%, 1.60%), and 0.13% (95% CI: 0.07%, 0.18%) changes in HR, QRS and QTc, respectively. Compared to the other pollutants, the estimates of PM2.5 remained the most stable across all two-pollutant models. Similarly, significant associations were observed between living closer to a major roadway and higher HR, QRS and QTc. Stratified analyses showed generally greater association estimates in older people, males, smokers, alcohol drinkers, and those with obesity, hypertension and diabetes. Conclusions Long-term exposure to ambient air pollution was associated with cardiac conduction abnormalities in Chinese adults, especially in older people, males, smokers, alcohol drinkers, and those with cardiometabolic risk factors. PM2.5 may be the most stable pollutant to reflect the associations.

Objective. To estimate the additive interaction of body mass index (BMI) and family history of hypertension (FHH) on hypertension and explore whether the interaction could be influenced by behavioural risk factors. Methods. The cross-sectional data on 5791 participants were from the China National Health Survey in Gansu province in 2016. We assessed the additive interaction by calculating the relative excess risk due to interaction (RERI), the attributable proportion due to interaction (AP), and the synergy index (SI). Results. ORs for hypertension were highest in Han (13.52, 95% CI: 9.45 to 19.34) and Yugur (13.85, 95% CI: 8.48 to 22.63) with the combination of obesity and FHH. The interaction of BMI and FHH was significant in Han people, with the RERI, AP, and SI and their 95% CIs being 2.48 (1.13 to 3.82), 0.33 (0.19 to 0.47), and 1.61 (1.26 to 2.07) for overweight and FHH and 6.32 (1.91 to 10.73), 0.47 (0.27 to 0.67), and 2.02 (1.33 to 3.07) for obesity and FHH, respectively. The interaction of BMI and FHH was not significant in Yugur people. Adjustment for behavioural risk factors had little influence on the interactions, and risks of hypertension remained increased. Conclusions. BMI and FHH were associated with hypertension, and the interaction of BMI and FHH on hypertension was significant in Han but not in Yugur people. Behavioural risk factors had little influence on the associations and interactions. The exacerbation of hypertension risks by overweight or obesity in hypertension families deserves attention in weight control and community care.

Objective. The effect of adiposity on hypertension among Uyghur Chinese is not clear. This study aimed to compare the effect of BMI and its optimal cut-off value in identifying hypertension in Uyghur and Han adults in China. Methods. By using a multistage stratified sampling method, 3072 Uyghur and 3195 Han adults underwent questionnaire interview, physical examination, and biochemical tests. Age- and sex-standardized prevalence of hypertension was calculated. Adjusted odds ratios for adiposity associated with hypertension were estimated. ROC analyses were used for assessing the ethnic and sex specific optimal BMI cut-off values in identifying hypertension. Results. Both in Uyghur and Han, increased BMI was consistent with the elevated systolic and diastolic blood pressure. Although more Uyghur were overweight/obese, their standardized prevalence of hypertension (17.87%) was lower than that of Han (20.28%). Han adults had 1.42 times odds than Uyghur of hypertension. The adjusted ORs of overweight and obesity were 2.67 and 6.04 in Uyghur and 2.74 and 7.58 in Han. In male, the optimal cut-off values of BMI identifying hypertension in Uyghur and Han were 24.6 kg/m2 and 24.9 kg/m2 , respectively, but the correspond values in Uyghur and Han females were 27.2 kg/m2 and 25.0 kg/m2. Conclusions. Adiposity had strong effect on hypertension, but this effect was less strong in Uyghur female than in Han female.

OBJECTIVE This study aimed to investigate the prevalence of dyslipidemia and its risk factors in children and adolescents aged 7 to 18 years in China. METHODS A cross-sectional study was conducted from November, 2013 to July, 2014. A total of 2283 children and adolescents from urban and rural areas in Hainan (South China) and Shaanxi Provinces (Northwest China) were selected using multi-stage stratified cluster sampling method. Each participant underwent anthropometric and serum biochemical tests which included serum lipids and hepatitis B virus surface antigen (HBsAg). RESULTS The overall prevalence of high total cholesterol (TC), high triglyceride (TG), high low-density lipoprotein cholesterol (LDL-C), low high-density lipoprotein cholesterol (HDL-C), hyperlipidemia and dyslipidemia were 6.5%, 7.5%, 5.2%, 9.1%, 14.3%, and 20.6%, respectively. After standardization by age, girls had higher prevalence of high TC (8.2%), high LDL-C (6.6%), and hyperlipidemia (16.4%), but lower prevalence of low HDL-C (8.21%) than boys (4.2%, 3.4%, 11.9%, and 11.3%, respectively). The risk of dyslipidemia increased with age (OR = 1.067, 95% CI: 1.030-1.106). Boys had a decreased risk of dyslipidemia (OR = 0.798, 95% CI: 0.640-0.994). The restricted cubic spline revealed a linear relationship between BMI and the risk of dyslipidemia (P

The study aimed to explore the independent association between expanded normal weight obesity categories and blood pressure among adults aged 20–80 years in China. By cross-sectional design, a total of 4279 adults living in Shaanxi Province, China, were selected from communities via multi-stage stratified cluster sampling in 2014. Information on anthropometric, body composition and blood pressure was collected and analysed. Expanded normal weight obesity (ENWO) categories were used to identify the level of bodyweight based on the combination of body mass index (BMI) and body fat percentage (BFP) categories. The age- and sex-standardised prevalence of hypertension increased within ENWO groups, from 10.12% in the underweight-low body fat group to 45.92% in the obesity-high body fat group. In under or normal weight participants, body fat percentage was found independently associated with hypertension in men, with an adjusted odds ratio of 3.69 in the fourth quartile of BFP compared with the first one. However, this effect was not observed in women. BFP was independently associated with increased risk of hypertension, especially in men. People with normal BMI should be re-identified as a high-risk population based on BFP level when it comes to hypertension prevention in primary healthcare settings.

We perform a theoretical analysis of the secondorder in-plane acceleration sensitivity of a Y-cut quartz thickness- shear mode resonator. The second-order nonlinear theory of elasticity for anisotropic crystals is used to determine the biasing fields in the resonator under in-plane acceleration. The acceleration-induced frequency shift is determined from a perturbation analysis based on the plate equations for small-amplitude vibrations superposed on a finite bias. We show that, whereas the first-order acceleration-induced frequency shift is zero for a structurally symmetric resonator under in-plane acceleration, the second-order frequency shift is nonzero and is quadratic in the acceleration. As the fourth-order nonlinear elastic constants of quartz have never been measured, we can only estimate the magnitude of the second-order frequency shift. For a particular case of interest, we find Δω/ω0 ~ 10(-18), 10(-16), and 10(-14) when the acceleration is 1, 10, and 100 g, respectively.

We study free vibration of a thickness-shear mode crystal resonator of AT-cut quartz. The resonator is a rectangular plate partially and symmetrically electroded at the center with rectangular electrodes. A single-mode, three-dimensional equation governing the thickness-shear displacement is used. A Fourier series solution is obtained. Numerical results calculated from the series show that there exist trapped thickness-shear modes whose vibration is mainly under the electrodes and decays rapidly outside the electrodes. The effects of the electrode size and thickness on the trapped modes are examined.

The thickness-shear and thickness-twist vibrations of a finite and partially electroded AT-cut quartz resonator are investigated. The equations of anisotropic elasticity are used with the omission of the small elastic constant c56. An analytical solution is obtained using Fourier series from which the free vibration resonant frequencies, mode shapes, and energy trapping are calculated and examined.

We study thickness-shear and thickness-twist free vibrations of a finite AT-cut quartz resonator with mis- matched electrodes. The equations of anisotropic elasticity are used with the omission of the small elastic constant c56. An analytical solution is obtained using Fourier series from which the resonant frequencies, mode shapes, and vibration confinement resulting from the electrode inertia are calculated and examined.

We study thickness-shear and thickness-twist vibrations of an AT-cut quartz plate mesa resonator with stepped thickness. The equations of anisotropic elasticity are used with the omission of the small elastic constant c(56). An analytical solution is obtained using Fourier series from which the resonant frequencies, mode shapes, and energy trapping are calculated and examined. The solution shows that a mesa resonator exhibits strong energy trapping of thickness-shear and thickness-twist modes, and that the trapping is sensitive to some of the structural parameters of the resonator.

AimsTo investigate the prevalence, ethnic differences and associated risk factors for pterygium in Han and Manchu populations aged 40–79 years in Hebei province, China.DesignCross-sectional study, as a part of the China National Health Survey.SettingHebei province, China.ParticipantsA multistage cluster sampling method with urbanisation level-based stratification was used to select participants for this study. A total of 4591 individuals over 40 years were recruited for this study. Inclusive criteria: (1) residents who had been living in Hebei for more than 1 year; (2) Han individuals with both parents being Han, or Manchu individuals with both parents being Manchu; (3) underwent ophthalmic examinations and (4) information in the questionnaire was complete.Main outcome measuresMultiple logistic regression analysis was used to evaluate the association between pterygium prevalence and factors of interest.ResultsA total of 3790 individuals (2351 Hans and 1439 Manchus) met the study criteria, of which 248 were diagnosed with pterygium (6.5%). There was no significant difference between the prevalence rates in Hans (6.2%) and Manchus (7.2%) (p=0.232). Multivariate analysis revealed that the risk factors for grade 2 or higher pterygium were increasing age (pConclusionThe overall prevalence of pterygium in Han and Manchu population in Hebei, China was approximately 6.1%. There were no differences in the prevalence of pterygium between Hans and Manchus, and the race was not a risk factor. This is the first study to report on the positive association between premature menopause and pterygium in females and between higher HDL levels and pterygium in males.

We study shear-horizontal motions of a piezoelectric ceramic cylinder with an oblate elliptical cross section and axial poling. Exact thickness-shear and thickness-twist vibration modes are obtained. These modes show energy trapping, i.e., the vibration is mainly confined near the thick, central region and decays to almost nothing near the edges. The results are useful for the understanding and design of contoured piezoelectric resonators for strong energy trapping.

We study the effects of couplings to flexure and face-shear modes on the admittance of an AT-cut quartz plate thickness-shear mode resonator. Mindlin's two-dimensional equations for piezoelectric plates are employed. Electrically forced vibration solutions are obtained for three cases: pure thickness-shear mode alone; two coupled modes of thickness shear and flexure; and three coupled modes of thickness shear, flexure, and face shear. Admittance is calculated and its dependence on the driving frequency and the length/thickness ratio of the resonator is examined. Results show that near the thickness-shear resonance, admittance assumes maxima, and that for certain values of the length/thickness ratio, the coupling to flexure causes severe admittance drops, while the coupling to the face-shear mode causes additional admittance changes that were previously unknown and hence are not considered in current resonator design practice.