313 research outputs found

    Waist Circumference Change is Associated with Blood Pressure Change Independent of BMI Change

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    Objective: This study aimed to understand how an increase in abdominal adiposity relative to overall adiposity is associated with blood pressure (BP) change. Methods: A sex-stratified mixed linear model was used to examine the association (95% CI) between annual changes in waist circumference (WC) and systolic blood pressure and diastolic blood pressure, estimated from two to eight repeated measures across the 1993-2015 China Health and Nutrition Survey, among 5,742 men and 5,972 women (18-66 years) with no history of antihypertension medication use. Results: The association between annual WC change and BP change remained statistically significant but was attenuated after controlling for annual BMI change, regardless of baseline abdominal obesity or overweight status. Each 10-cm annual WC gain in men and women was associated with a 0.98-mm Hg (95% CI: 0.61-1.35) and a 0.97-mm Hg (95% CI: 0.62-1.32) annual increase in systolic blood pressure and a 1.13-mm Hg (95% CI: 0.87-1.38) and a 0.74-mm Hg (95% CI: 0.51-0.97) annual increase in diastolic blood pressure, respectively, independent of annual BMI change. Conclusions: WC gain may elevate BP even in the absence of BMI gain. BP management that addresses only BMI gain could overlook individuals at risk of elevated BP who have increased WC but not BMI

    Accounting for Selectivity Bias and Correlation Across the Sequence from Elevated Blood Pressure to Hypertension Diagnosis and Treatment

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    BACKGROUND It is unknown whether efforts to reduce hypertension burden in countries with very high prevalence, would be more effective if directed at hypertension diagnosis vs. treatment. Most analyses do not address bias and correlation across the sequence from elevated blood pressure (BP) to hypertension diagnosis and treatment, leading to potentially misleading findings. METHODS Using data spanning 18 years of the China Health and Nutrition Survey (n = 18,926; ages 18-75 years), we used an innovative 3-step, integrated system of equations to predict the sequence from: (i) elevated BP (systolic/diastolic BP ≥ 140/90 mm Hg) to (ii) diagnosed hypertension conditional on elevated BP, and to (iii) treatment (medication use) conditional on diagnosis, accounting for measured and unmeasured individual- and community-level confounders at each of the 3 steps. We compared results to separate traditional logistic regression models without control for unmeasured confounding. RESULTS Using our 3-step model, elevated BP increased from 12.6% and 8.5% (1991) to 36.8% and 29% (2009) in men and women, respectively, but diagnosis remained under 50%. We found widening disparities in hypertension diagnosis (higher hypertension at lower vs. higher education (difference of 2% in 1991 that widened to 5% in 2009)) and narrowing disparities in education (difference of 6% in 1991 to 4% in 2009) and insurance status (difference of 7% in 1991 to 2% in 2009) for treatment. CONCLUSIONS Our 3-step model improved model fit over traditionally used models. Our findings highlight serious barriers to hypertension diagnosis in Chinese adults, particularly among men and individuals of low attained education

    Is a Hypertension Diagnosis Associated With Improved Dietary Outcomes Within 2 to 4 Years? A Fixed-Effects Analysis From the China Health and Nutrition Survey

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    Background: Evidence shows that dietary factors play an important role in blood pressure. However, there is no clear understanding of whether hypertension diagnosis is associated with dietary modifications. The aim of this study is to estimate the longitudinal association between hypertension diagnosis and subsequent changes (within 2–4 years) in dietary sodium, potassium, and sodium-potassium (Na/K) ratio. Methods and Results: We included adults (18–75 years, n=16 264) from up to 9 waves (1991–2015) of the China Health and Nutrition Survey. Diet data were collected using three 24-hour dietary recalls and a household food inventory. We used fixed-effects models to estimate the association between newly self-reported diagnosed hypertension and subsequent within-individual changes in sodium, potassium, and Na/K ratio. We also examined changes among couples and at the household level. Results suggest that on average, men who were diagnosed with hypertension decreased their sodium intake by 251 mg/d and their Na/K ratio by 0.19 within 2 to 4 years after diagnosis (P<0.005). Among spouse pairs, sodium intake and Na/K ratio of women decreased when their husbands were diagnosed (P<0.05). Household average sodium density and Na/K ratio decreased, and household average potassium density increased after a man was diagnosed. In contrast, changes were not statistically significant when women were diagnosed. Conclusions: Our findings suggest that hypertension diagnosis for a man may result in modest dietary improvements for him, his wife, and other household members. Yet, diagnosis for a woman does not seem to result in dietary changes for her or her household members

    Quintessential Maldacena-Maoz Cosmologies

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    Maldacena and Maoz have proposed a new approach to holographic cosmology based on Euclidean manifolds with disconnected boundaries. This approach appears, however, to be in conflict with the known geometric results [the Witten-Yau theorem and its extensions] on spaces with boundaries of non-negative scalar curvature. We show precisely how the Maldacena-Maoz approach evades these theorems. We also exhibit Maldacena-Maoz cosmologies with [cosmologically] more natural matter content, namely quintessence instead of Yang-Mills fields, thereby demonstrating that these cosmologies do not depend on a special choice of matter to split the Euclidean boundary. We conclude that if our Universe is fundamentally anti-de Sitter-like [with the current acceleration being only temporary], then this may force us to confront the holography of spaces with a connected bulk but a disconnected boundary.Comment: Much improved exposition, exponent in Cai-Galloway theorem fixed, axionic interpretation of scalar explained, JHEP version. 33 pages, 3 eps figure

    Supergravity brane worlds and tachyon potentials

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    We study massless and massive graviton modes that bind on thick branes which are supergravity domain walls solutions in DD-dimensional supergravity theories where only the supergravity multiplet and the scalar supermultiplet are turned on. The domain walls are bulk solutions provided by tachyon potentials. Such domain walls are regarded as BPS branes of one lower dimension that are formed due to tachyon potentials on a non-BPS D-brane.Comment: RevTex4, 6 pages; version to appear in Phys. Rev.

    Binding Energy of Hydrogen-Like Impurities in Quantum Well Wires of InSb/GaAs in a Magnetic Field

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    The binding energy of a hydrogen-like impurity in a thin size-quantized wire of the InSb/GaAs semiconductors with Kane’s dispersion law in a magnetic fieldBparallel to the wire axis has been calculated as a function of the radius of the wire and magnitude ofB, using a variational approach. It is shown that when wire radius is less than the Bohr radius of the impurity, the nonparabolicity of dispersion law of charge carriers leads to a considerable increase of the binding energy in the magnetic field, as well as to a more rapid growth of binding energy with growth ofB

    Six-Year Incidence of Cardiometabolic Risk Factors in a Population-Based Cohort of Chinese Adults Followed From 2009 to 2015

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    Background: China faces a substantial burden from cardiometabolic diseases, but longitudinal studies on a wide range of cardiometabolic risk factors are limited. We examined the 6-year incidence of 8 cardiometabolic risk factors in a diverse, population-based cohort. Methods and Results: In the China Health and Nutrition Survey, anthropometry, blood pressure, and fasting blood samples were collected from 9621 adults (47.6% men) aged 18 to 99 years in 2009 who were followed into 2015. Using inverse probability weights to account for loss to follow-up, we estimated the 6-year incidence of 8 cardiometabolic risk factors and compared the incidence of each risk factor across age groups using inverse probability–weighted sex-stratified logistic regression models. Incidence was noted for the following cardiometabolic risk factors during 2009–2015: hypertension (systolic/diastolic blood pressure ≥140/90 mm Hg; men: 29.2%; women: 24.9%), high waist circumference/height ratio (≥0.5; men: 42.4%; women: 43.8%), and high total to HDL (high-density lipoprotein) cholesterol ratio (≥5; men: 17.0%; women: 14.5%). Older men and women (aged ≥65 years) had the highest incidence of hypertension. Incidence of high waist circumference/height ratio and high LDL (low-density lipoprotein) cholesterol (≥130 mg/dL) was highest among older (aged ≥65 years) women, whereas incidence of overweight (body mass index ≥25) and high triglycerides (≥150 mg/dL) was highest among younger (aged 18–35 and 35–50 years) men. Conclusions: We found increases in cardiometabolic risk among Chinese adults during this recent, short, 6-year period that are higher than previous studies in China. The higher incidence of overweight and elevated dyslipidemia markers in younger versus older men portends an increasing burden of cardiometabolic diseases in China as the younger population ages

    Strengthening Causal Inference in Exposomics Research: Application of Genetic Data and Methods

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    Advances in technologies to measure a broad set of exposures have led to a range of exposome research efforts. Yet, these efforts have insufficiently integrated methods that incorporate genetic data to strengthen causal inference, despite evidence that many exposome-associated phenotypes are heritable. OBJECTIVE: We demonstrate how integration of methods and study designs that incorporate genetic data can strengthen causal inference in exposomics research by helping address six challenges: reverse causation and unmeasured confounding, comprehensive examination of phenotypic effects, low efficiency, replication, multilevel data integration, and characterization of tissue-specific effects. Examples are drawn from studies of biomarkers and health behaviors, exposure domains where the causal inference methods we describe are most often applied. DISCUSSION: Technological, computational, and statistical advances in genotyping, imputation, and analysis, combined with broad data sharing and cross-study collaborations, offer multiple opportunities to strengthen causal inference in exposomics research. Full application of these opportunities will require an expanded understanding of genetic variants that predict exposome phenotypes as well as an appreciation that the utility of genetic variants for causal inference will vary by exposure and may depend on large sample sizes. However, several of these challenges can be addressed through international scientific collaborations that prioritize data sharing. Ultimately, we anticipate that efforts to better integrate methods that incorporate genetic data will extend the reach of exposomics research by helping address the challenges of comprehensively measuring the exposome and its health effects across studies, the life course, and in varied contexts and diverse populations
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