Predictive health: the imminent revolution in health care

Restless legs syndrome, periodic limb movements of sleep, and subclinical cardiovascular disease

Restless legs syndrome (RLS) and periodic limb movements of sleep (PLMS) have been variably implicated in risk for cardiovascular disease (CVD), but there is lack of consensus on these relationships. We sought to assess subclinical CVD measures and RLS/PLMS in a large cohort to further evaluate these associations. The Emory Center for Health Discovery and Well Being cohort is composed of employed adults, with subclinical CVD measures including endothelial function (flow-mediated vasodilation), microvascular function (reactive hyperemia index, RHI), arterial stiffness (pulse wave velocity and augmentation index), and carotid intima-media thickness (cIMT). Participants were grouped based on presence (N = 50) or absence (N = 376) of RLS and subclinical CVD measures compared between groups. A subset of participants (n = 40) underwent ambulatory monitoring for PLMS and obstructive sleep apnea. PLMS association with subclinical CVD measures was assessed. RLS status was significantly associated with flow-mediated dilation in univariate analyses but not after controlling for potential confounders; RLS was not associated with other subclinical CVD measures. PLMS were significantly correlated with the RHI, augmentation index, and cIMT in univariate analyses; only the association between PLMS and cIMT remained significant (p = 0.04) after controlling for RLS status, age, apnea-hypopnea index, hyperlipidemia, and hypertension. The observed association between higher PLMS and greater cIMT suggests that PLMS may be a marker of subclinical CVD. Further work is needed to determine the relationship between PLMS and CVD risk.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41105-023-00497-7.

Discovery of phytochelatins in human urine: Evidence for function in selenium disposition and protection against cadmium

This report identifies, for the first time, a phytochelatin compound, phytochelatin 2 [γ-E-C-γ-E-C-G], and related metabolites in human urine. Phytochelatins are metal-binding peptides produced by plants. They are present in nearly all human diets, due to their ubiquity in plants. The urinary concentration of phytochelatin 2 among 143 adults was in the low micromolar range, and phytochelatin 2 and its metabolites had differential correlations with urinary selenium and toxic metals. Activities of ingested phytochelatins are largely undescribed. Observed urinary metal interactions were investigated further in cell and animal models. Selenite reacted with phytochelatin to form a phytochelatin selenotrisulfide, and the preformed selenotrisulfide showed increased selenium uptake by renal proximal tubule cells. In vivo studies further showed that oral phytochelatin increased renal selenium content and decreased lung cadmium in mice. Presence of phytochelatin in human urine combined with its function in selenium and heavy metal distribution present a new route by which diet may influence metal disposition and bioavailability.

Microbial metabolite delta-valerobetaine is a diet-dependent obesogen

Obesity and obesity-related metabolic disorders are linked to the intestinal microbiome. However, the causality of changes in the microbiome-host interaction affecting energy metabolism remains controversial. Here, we show the microbiome-derived metabolite δ-valerobetaine (VB) is a diet-dependent obesogen that is increased with phenotypic obesity and is correlated with visceral adipose tissue mass in humans. VB is absent in germ-free mice and their mitochondria but present in ex-germ-free conventionalized mice and their mitochondria. Mechanistic studies in vivo and in vitro show VB is produced by diverse bacterial species and inhibits mitochondrial fatty acid oxidation through decreasing cellular carnitine and mitochondrial long-chain acyl-coenzyme As. VB administration to germ-free and conventional mice increases visceral fat mass and exacerbates hepatic steatosis with a western diet but not control diet. Thus, VB provides a molecular target to understand and potentially manage microbiome-host symbiosis or dysbiosis in diet-dependent obesity.

Developing a synthetic control group using electronic health records: Application to a single-arm lifestyle intervention study

The electronic health records (EHR) infrastructure offers a tremendous resource for identifying controls who match the characteristics of study participants in a single-arm trial. The objectives are to (1) demonstrate the feasibility of curating a synthetic control group for an existing study cohort through EHR data extraction and (2) evaluate the effect of a lifestyle intervention on selected cardiovascular health metrics. A total of 711 university employees were recruited between 2008 and 2012 to participate in a health partner intervention to improve cardiovascular health and were followed for five years. Data of nearly 8000 eligible subjects were extracted from the EHR to create a synthetic control cohort during the same study period. To minimize confounding, crude comparison, exact matching, propensity score matching, and doubly robust estimation were used to compare the selected cardiovascular health metrics at 1 and 5 years of follow-up. Blood pressure and body mass index improved in the intervention group compared to the EHR synthetic controls. The findings of changes in lipid measurements were somewhat unexpected. When analyzing the subgroup without lipid-lowering medications, the intervention group exhibited better control of cholesterol levels over time than did our synthetic controls. Some measurements in the EHR system may be more robust for synthetic selection than others. EHR synthetic controls can provide an alternative to estimate intervention effects appropriately in single-arm studies for these measurements.

A scalable workflow to characterize the human exposome

Complementing the genome with an understanding of the human exposome is an important challenge for contemporary science and technology. Tens of thousands of chemicals are used in commerce, yet cost for targeted environmental chemical analysis limits surveillance to a few hundred known hazards. To overcome limitations which prevent scaling to thousands of chemicals, we develop a single-step express liquid extraction and gas chromatography high-resolution mass spectrometry analysis to operationalize the human exposome. We show that the workflow supports quantification of environmental chemicals in human plasma (200 µL) and tissue (≤100 mg) samples. The method also provides high resolution, sensitivity and selectivity for exposome epidemiology of mass spectral features without a priori knowledge of chemical identity. The simplicity of the method can facilitate harmonization of environmental biomonitoring between laboratories and enable population level human exposome research with limited sample volume.

Large scale enzyme based xenobiotic identification for exposomics

Advances in genomics have revealed many of the genetic underpinnings of human disease, but exposomics methods are currently inadequate to obtain a similar level of understanding of environmental contributions to human disease. Exposomics methods are limited by low abundance of xenobiotic metabolites and lack of authentic standards, which precludes identification using solely mass spectrometry-based criteria. Here, we develop and validate a method for enzymatic generation of xenobiotic metabolites for use with high-resolution mass spectrometry (HRMS) for chemical identification. Generated xenobiotic metabolites were used to confirm identities of respective metabolites in mice and human samples based upon accurate mass, retention time and co-occurrence with related xenobiotic metabolites. The results establish a generally applicable enzyme-based identification (EBI) for mass spectrometry identification of xenobiotic metabolites and could complement existing criteria for chemical identification.

Relationships between plasma apelin and adiponectin with normal weight obesity, body composition, and cardiorespiratory fitness in working adults

Background

A significant proportion of adults have normal weight obesity (NWO), defined as a normal body mass index (BMI) but disproportionately high body fat percentage. Individuals with NWO may have increased risk of cardiometabolic disorders and lower exercise tolerance, but it is unclear if this obesity phenotype is linked with dysregulated production of adipokines or myokines such as adiponectin and apelin, respectively.

Methods

This cross-sectional, secondary analysis included 177 working adults (mean age 49.6 ± 9.9 yrs, 64% female). Plasma high-molecular weight adiponectin and apelin levels were measured by ELISA. Body composition and fat distribution were assessed using dual energy X-ray absorptiometry. Exercise tolerance (VO₂ maximum) was determined by treadmill testing. NWO was defined as a BMI <25 kg/m² and body fat >30% for women or >23% for men. Participants were categorized as lean, NWO, or overweight-obese.

Results

A total of 14.7% of subjects were categorized as lean, 23.7% as having NWO, and 61.6% as having overweight-obesity. Plasma adiponectin levels were elevated in the overweight-obesity group (P < 0.05) compared to the lean and NWO groups, which did not differ from each other (P > 0.05). Adiponectin concentrations were inversely associated with BMI, fat mass, fat mass percent, visceral fat, and trunk to leg fat ratio and positively associated with leg fat mass (all P < 0.001). Plasma apelin levels were similar between the three body composition groups (P < 0.05) and were not significantly associated with any body composition indices. Apelin concentrations were inversely related to VO₂ maximum (β = −0.03 ± 0.01, p = 0.002).

Conclusion

Plasma adiponectin and apelin levels did not distinguish between lean and NWO groups. Positive relationships with leg fat mass and adiponectin suggest the importance of assessing body composition and fat distribution when studying adipokines and cardiometabolic disorders. Further investigations are needed to understand relationships between exercise, body composition, and apelin secretion.

Vascular Regenerative Capacity and the Obesity Paradox in Coronary Artery Disease

[Figure: see text].

Plasma high-resolution metabolomics identifies linoleic acid and linked metabolic pathways associated with bone mineral density

BACKGROUND & AIMS

There is a considerable degree of variation in bone mineral density (BMD) within populations. Use of plasma metabolomics may provide insight into established and novel determinants of BMD variance, such as nutrition and gut microbiome composition, to inform future prevention and treatment strategies for loss of BMD. Using high-resolution metabolomics (HRM), we examined low-molecular weight plasma metabolites and nutrition-related metabolic pathways associated with BMD.

METHODS

This cross-sectional study included 179 adults (mean age 49.5 ± 10.3 yr, 64% female). Fasting plasma was analyzed using ultra-high-resolution mass spectrometry with liquid chromatography. Whole body and spine BMD were assessed by dual energy X-ray absorptiometry and expressed as BMD (g/cm2) or Z-scores. Multiple linear regression, pathway enrichment, and module analyses were used to determine key plasma metabolic features associated with bone density.

RESULTS

Of 10,210 total detected metabolic features, whole body BMD Z-score was associated with 710 metabolites, which were significantly enriched in seven metabolic pathways, including linoleic acid, fatty acid activation and biosynthesis, and glycerophospholipid metabolism. Spine BMD was associated with 970 metabolites, significantly enriched in pro-inflammatory pathways involved in prostaglandin formation and linoleic acid metabolism. In module analyses, tryptophan- and polyamine-derived metabolites formed a network that was significantly associated with spine BMD, supporting a link with the gut microbiome.

CONCLUSIONS

Plasma HRM provides comprehensive information relevant to nutrition and components of the microbiome that influence bone health. This data supports pro-inflammatory fatty acids and the gut microbiome as novel regulators of postnatal bone remodeling.

Application of high-resolution metabolomics to identify biological pathways perturbed by traffic-related air pollution

BACKGROUND

Substantial research has investigated the adverse effects of traffic-related air pollutants (TRAP) on human health. Convincing associations between TRAP and respiratory and cardiovascular diseases are known, but the underlying biological mechanisms are not well established. High-resolution metabolomics (HRM) is a promising platform for untargeted characterization of molecular mechanisms between TRAP and health indexes.

OBJECTIVES

We examined metabolic perturbations associated with short-term exposures to TRAP, including carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), fine particulate matter (PM2.5), organic carbon (OC), and elemental carbon (EC) among 180 participants of the Center for Health Discovery and Well-Being (CHDWB), a cohort of Emory University-affiliated employees.

METHODS

A cross-sectional study was conducted on baseline visits of 180 CHDWB participants enrolled during 2008-2012, in whom HRM profiling was determined in plasma samples using liquid chromatography-high-resolution mass spectrometry with positive and negative electrospray ionization (ESI) modes. Ambient pollution concentrations were measured at an ambient monitor near downtown Atlanta. Metabolic perturbations associated with TRAP exposures were assessed following an untargeted metabolome-wide association study (MWAS) framework using feature-specific Tobit regression models, followed by enriched pathway analysis and chemical annotation.

RESULTS

Subjects were predominantly white (76.1%) and non-smokers (95.6%), and all had at least a high school education. In total, 7821 and 4123 metabolic features were extracted from the plasma samples by the negative and positive ESI runs, respectively. There are 3421 features significantly associated with at least one air pollutant by negative ion mode, and 1691 features by positive ion mode. Biological pathways enriched by features associated with the pollutants are primarily involved in nucleic acids damage/repair (e.g., pyrimidine metabolism), nutrient metabolism (e.g., fatty acid metabolism), and acute inflammation (e.g., histidine metabolism and tyrosine metabolism). NO2 and EC were associated most consistently with these pathways. We confirmed the chemical identity of 8 metabolic features in negative ESI and 2 features in positive ESI, including metabolites closely linked to oxidative stress and inflammation, such as histamine, tyrosine, tryptophan, and proline.

CONCLUSIONS

We identified a range of ambient pollutants, including components of TRAP, associated with differences in the metabolic phenotype among the cohort of 180 subjects. We found Tobit models to be a robust approach to handle missing data among the metabolic features. The results were encouraging of further use of HRM and MWAS approaches for characterizing molecular mechanisms underlying exposure to TRAP.

Physical Fitness but Not Diet Quality Distinguishes Lean and Normal Weight Obese Adults

BACKGROUND

Individuals with normal weight obesity (NWO) have increased cardiometabolic disease and mortality risk, but factors contributing to NWO development are unknown.

OBJECTIVE

The objective of this study was to determine whether diet quality scores and physical fitness levels differed between adults classified as lean, NWO, and overweight-obese. Secondary objectives of the study were to compare clinical biomarkers and food groups and macronutrient intakes between the three groups, and to test for associations between body composition components with diet quality scores and physical fitness levels.

DESIGN

This is a secondary data analysis from a cross-sectional study that included metropolitan university and health care system employees. Body composition was measured by dual energy x-ray absorptiometry. Individuals with a body mass index <25 kg/m2 and body fat >23% for men and >30% for women were classified as having NWO. Alternate Healthy Eating Index, Dietary Approaches to Stop Hypertension score, and Mediterranean Diet Score were calculated from Block food frequency questionnaires. Physical fitness was assessed by measuring maximal oxygen uptake (VO2 maximum) during treadmill testing.

PARTICIPANTS/SETTING

This study included 693 adults (65% women, mean age 48.9 ± 11.5 years) enrolled between 2007 and 2013 in Atlanta, GA.

MAIN OUTCOME MEASURES

The main outcome measures were Alternate Healthy Eating Index, Dietary Approaches to Stop Hypertension, and Mediterranean Diet Score diet quality scores and maximal oxygen uptake.

STATISTICAL ANALYSES

Multiple linear regression analyses with post hoc comparisons were used to investigate group differences in fitness, diet quality, and biomarkers. Regression analyses were also used to examine relationships between diet quality scores and fitness with body composition.

RESULTS

VO2 maximum was significantly lower in the NWO compared with the lean group (36.2 ± 0.8 mL/min/kg vs 40.2 ± 1.0 mL/min/kg; P < 0.05). Individuals with NWO reported similar diet quality to lean individuals and more favorable Alternate Healthy Eating Index and Dietary Approaches to Stop Hypertension scores than individuals with overweight-obesity (P < 0.05). Diet quality scores and physical fitness levels were inversely associated with percent body fat and visceral adipose tissue (P < 0.05), regardless of weight status. Individuals with NWO exhibited higher fasting blood insulin concentrations, insulin resistance, low-density lipoprotein cholesterol, and triglyceride levels, and significantly lower high-density lipoprotein cholesterol levels than lean individuals (P < 0.05).

CONCLUSIONS

Physical fitness was significantly decreased in individuals with NWO compared with lean individuals. Higher diet quality was associated with decreased total and visceral fat but did not distinguish individuals with NWO from lean individuals.

Sex Differences in Circulating Soluble Urokinase-Type Plasminogen Activator Receptor (suPAR) Levels and Adverse Outcomes in Coronary Artery Disease

Background

Women have higher circulating levels of soluble urokinase‐type plasminogen activator receptor (suPAR), and elevated suPAR is associated with cardiovascular risk. The independent association of sex with suPAR and the impact of sex on its association with cardiovascular risk are unknown.

Methods and Results

Plasma suPAR was measured using ELISA in 2 cohorts of 666 asymptomatic individuals (49 years, 65% women) and 4184 patients with coronary artery disease (63 years, 37% women). Independent association of sex with suPAR was studied using linear regression models adjusted for demographics, risk factors, and visceral adiposity in asymptomatic participants. Impact of sex on association of suPAR with all‐cause mortality was studied in patients with coronary artery disease using multivariable‐adjusted Cox models. Sex‐specific suPAR cutoffs for predicting all‐cause mortality were calculated. Asymptomatic women had 10% higher suPAR compared with men after adjusting for confounders, and visceral adiposity partly accounted for this association. Over a median follow‐up of 5.2 years, 795 deaths were recorded in patients with coronary artery disease. Log₂‐transformed suPAR was independently associated with mortality (hazard ratio per 1‐SD 1.72, 95% CI 1.60–1.85) and an interaction with sex was noted (P=0.005). Association of suPAR with mortality was slightly weaker in women (hazard ratio 1.61, 95% CI 1.41–1.83) compared with men (hazard ratio 1.83, 95% CI 1.67–2.00). However, using sex‐specific suPAR cut‐offs (4392 pg/mL for women and 3187 pg/mL for men), a similar mortality incidence was observed for both sexes (38.5% and 35.5%, respectively, P=0.3).

Conclusions

Women have 10% higher plasma suPAR levels compared with men. Elevated sex‐specific plasma suPAR levels are equally predictive of risk of adverse events in both sexes.

Plasma High-Resolution Metabolomics Differentiates Adults with Normal Weight Obesity from Lean Individuals

OBJECTIVE

This study explored underlying metabolism-related dysfunction by examining metabolomic profiles in adults categorized as lean, as having normal weight obesity (NWO), or as having overweight/obesity.

METHODS

Participants (N = 179) had fasting plasma analyzed by liquid chromatography and high-resolution mass spectrometry for high-resolution metabolomics. Body composition was assessed by dual-energy x-ray absorptiometry. NWO was defined as BMI < 25 and body fat > 30% for women and > 23% for men. Differentiating metabolomic features were determined by using linear regression models and likelihood ratio tests with false discovery rate correction. Mummichog was used for pathway and network analyses.

RESULTS

A total of 222 metabolites significantly differed between the groups at a false discovery rate of q = 0.2. Linoleic acid, β-alanine, histidine, and aspartate/asparagine metabolism pathways were significantly enriched (all P < 0.01) by metabolites that were similarly upregulated in the NWO and overweight/obesity groups compared with the lean group. A module analysis linked branched-chain amino acids and amino acid metabolites as elevated in the NWO and overweight/obesity groups compared with the lean group (all P < 0.05).

CONCLUSIONS

Metabolomic profiles of individuals with NWO reflected similar metabolic disruption as those of individuals with overweight/obesity. High-resolution metabolomics may help identify people at risk for developing obesity-related disease, despite normal BMI.

Differences in Function and Comorbidities Between Older Adult Users and Nonusers of Chiropractic and Osteopathic Manipulation: A Cross-sectional Analysis of the 2012 National Health Interview Survey

OBJECTIVE

The purpose of this cross-sectional study was to compare functional limitations and comorbidity prevalence between older adult users and nonusers of chiropractic and osteopathic (DC/DO) manipulation to inform provider training.

METHODS

We conducted a secondary analysis of the 2012 National Health Interview Survey data. Adults age 65 or older who responded to the survey were included. Descriptive statistics are reported for adults who used DC/DO manipulation (vs nonusers) regarding function, comorbidities, musculoskeletal complaints, and medical services. Weighted percentages were derived using SAS and compared with χ² tests.

RESULTS

The DC/DO users were more often female, overweight or obese, and of white race than nonusers. More DC/DO users reported arthritis (55.3% vs 47.0%, <0.01) or asthma (15.0% vs 10.0%, P < .01) than nonusers; hypertension (61.9% vs 55.5%, P = .02) and diabetes (20.3% vs 15.7%, P = .02) were more prevalent in nonusers; and other comorbidities were comparable. The DC/DO users reported more joint pain/stiffness (55.7% vs 44.8%), chronic pain (19.8% vs 14.2%), low back pain (27.8% vs 18.4%), low back with leg pain (18.8% vs 10.6%), and neck pain (24.2% vs 13.1%) than nonusers (all P < .01). Functional limitations affected two-thirds overall, but DC/DO users reported more difficulties stooping and bending; other limitations were comparable. One in 9 reported activities of daily living or instrumental activities of daily living limitations; nonusers were more affected. Surgery was more common among DC/DO users (26.1% vs 19.3%, <0.01); emergency room visits were comparable.

CONCLUSION

Differences existed between older adult manipulation users and nonusers, especially surgical utilization, musculoskeletal complaints, and comorbidities; functional differences were modest. Our findings highlight areas for provider training and awareness regarding comorbidity burden and management needs in older patients who may simultaneously use manipulation and medical care for musculoskeletal complaints.

Missing value imputation for LC-MS metabolomics data by incorporating metabolic network and adduct ion relations

Motivation

Metabolomics data generated from liquid chromatography-mass spectrometry platforms often contain missing values. Existing imputation methods do not consider underlying feature relations and the metabolic network information. As a result, the imputation results may not be optimal.

Results

We proposed an imputation algorithm that incorporates the existing metabolic network, adduct ion relations even for unknown compounds, as well as linear and nonlinear associations between feature intensities to build a feature-level network. The algorithm uses support vector regression for missing value imputation based on features in the neighborhood on the network. We compared our proposed method with methods being widely used. As judged by the normalized root mean squared error in real data-based simulations, our proposed methods can achieve better accuracy.

Availability and implementation

The R package is available at http://web1.sph.emory.edu/users/tyu8/MINMA.

Contact

jiankang@umich.edu or tianwei.yu@emory.edu.

Supplementary information

Supplementary data are available at Bioinformatics online.

Insomnia Symptoms Are Associated With Abnormal Endothelial Function

BACKGROUND

Insomnia is a prevalent sleep disorder, and it has been increasingly associated with cardiovascular morbidity and mortality. The reasons for this relationship are not completely understood but may involve endothelial dysfunction. In this study, we hypothesized that insomnia symptoms would be associated with reduced endothelial function.

METHODS

Working adults (n = 496, 67.5% female, 78.6% white, mean age 48.7 [SD, 10.8] years, body mass index 28.2 [SD, 6.7] kg/m, diabetes 5.8%, hypertension 20.0%, hyperlipidemia 17.9%, heart disease 2.6%) enrolled in the Emory-Georgia Tech Predictive Health Institute study completed baseline demographic, clinical, depression (Beck Depression Inventory II), anxiety (General Anxiety Disorder 7), sleep (Pittsburg Sleep Quality Index), and noninvasive endothelial function (brachial artery flow-mediated dilation [FMD]) measures. Insomnia symptoms were defined as subjective sleep latency of 30 minutes or longer, nighttime or early morning awakenings, and/or sleep medication use occurring 3 times or more per week in the past month.

RESULTS

Insomnia symptoms were reported by 39.5% of participants. Multivariable regression models showed that insomnia symptoms, age, baseline artery diameter, and dyslipidemia were inversely related to FMD. After adjusting for age, baseline artery diameter, and dyslipidemia, participants reporting insomnia symptoms had lower FMD than did participants reporting better sleep (adjusted FMD mean, 6.13% [SD, 0.28%] vs 6.83% [SD, 0.26%], P = .035).

CONCLUSION

In this study, insomnia symptoms were associated with reduced FMD. Research examining the therapeutic benefits of treating insomnia on endothelial function and future cardiovascular risk is warranted.

Higher Mediterranean Diet Quality Scores and Lower Body Mass Index Are Associated with a Less-Oxidized Plasma Glutathione and Cysteine Redox Status in Adults

Background

Both systemic redox status and diet quality are associated with risk outcomes in chronic disease. It is not known, however, the extent to which diet quality influences plasma thiol/disulfide redox status.

Objective

The purpose of this study was to investigate the influence of diet, as measured by diet quality scores and other dietary factors, on systemic thiol/disulfide redox status.

Methods

We performed a cross-sectional study of 685 working men and women (ages ≥18 y) in Atlanta, GA. Diet was assessed by 3 diet quality scores: the Alternative Healthy Eating Index (AHEI), Dietary Approaches to Stop Hypertension (DASH), and the Mediterranean Diet Score (MDS). We measured concentrations of plasma glutathione (GSH), cysteine, their associated oxidized forms [glutathione disulfide (GSSG) and cystine (CySS), respectively], and their redox potentials (EhGSSG and EhCySS) to determine thiol/disulfide redox status. Linear regression modeling was performed to assess relations between diet and plasma redox after adjustment for age, body mass index (BMI), sex, race, and history of chronic disease.

Results

MDS was positively associated with plasma GSH (β = 0.02; 95% CI: 0.003, 0.03) and total GSH (GSH + GSSG) (β = 0.02; 95% CI: 0.003, 0.03), and inversely associated with the CySS:GSH ratio (β = -0.02; 95% CI: -0.04, -0.004). There were significant independent associations between individual MDS components (dairy, vegetables, fish, and monounsaturated fat intake) and varying plasma redox indexes (P < 0.05). AHEI and DASH diet quality indexes and other diet factors of interest were not significantly correlated with plasma thiol and disulfide redox measures.

Conclusion

Adherence to the Mediterranean diet was significantly associated with a favorable plasma thiol/disulfide redox profile, independent of BMI, in a generally healthy working adult population. Although longitudinal studies are warranted, these findings contribute to the feasibility of targeting a Mediterranean diet to improve plasma redox status.

Relation of Changes in Body Fat Distribution to Oxidative Stress

Android fat is a surrogate measure of visceral obesity in the truncal region. Both visceral adiposity and oxidative stress (OS) are linked to cardiometabolic risk factors and clinical cardiovascular disease. However, whether body fat distribution (android vs gynoid) is associated with OS remains unknown. We hypothesized that increased android fat will be associated with greater OS. Body fat distribution and markers of OS, including plasma levels of reduced (cysteine and glutathione) and oxidized (cystine and glutathione disulfide) aminothiols, were estimated in 711 volunteers (67% female, 23% black, mean age 48 ± 11) enrolled in the Emory Georgia Tech Predictive Health study. At 1 year, 498 subjects had repeat testing. At baseline, anthropometric and fat distribution indexes, including body mass index, waist circumference, weight/hip ratio, and android and gynoid fat mass correlated with lower plasma concentrations of glutathione and higher cystine levels indicative of higher OS. At 1 year, the change in android but not gynoid fat mass or body mass index negatively correlated with the change in the plasma glutathione level after adjustment for cardiovascular risk factors. Increased body fat, specifically android fat mass, is an independent determinant of systemic OS, and its change is associated with a simultaneous change in OS, measured as plasma glutathione. In conclusion, our findings suggest that excess android or visceral fat contributes to the development of cardiovascular disease through modulating OS.

Network Marker Selection for Untargeted LC-MS Metabolomics Data

Untargeted metabolomics using high-resolution liquid chromatography-mass spectrometry (LC-MS) is becoming one of the major areas of high-throughput biology. Functional analysis, that is, analyzing the data based on metabolic pathways or the genome-scale metabolic network, is critical in feature selection and interpretation of metabolomics data. One of the main challenges in the functional analyses is the lack of the feature identity in the LC-MS data itself. By matching mass-to-charge ratio (m/z) values of the features to theoretical values derived from known metabolites, some features can be matched to one or more known metabolites. When multiple matchings occur, in most cases only one of the matchings can be true. At the same time, some known metabolites are missing in the measurements. Current network/pathway analysis methods ignore the uncertainty in metabolite identification and the missing observations, which could lead to errors in the selection of significant subnetworks/pathways. In this paper, we propose a flexible network feature selection framework that combines metabolomics data with the genome-scale metabolic network. The method adopts a sequential feature screening procedure and machine learning-based criteria to select important subnetworks and identify the optimal feature matching simultaneously. Simulation studies show that the proposed method has a much higher sensitivity than the commonly used maximal matching approach. For demonstration, we apply the method on a cohort of healthy subjects to detect subnetworks associated with the body mass index (BMI). The method identifies several subnetworks that are supported by the current literature, as well as detects some subnetworks with plausible new functional implications. The R code is available at http://web1.sph.emory.edu/users/tyu8/MSS.

Effects of a Health-Partner Intervention on Cardiovascular Risk

BACKGROUND

Lifestyle modifications are first-line measures for cardiovascular disease prevention. Whether lifestyle intervention also preserves cardiovascular health is less clear. Our study examined the role of a Health Partner-administered lifestyle intervention on metrics of ideal cardiovascular health.

METHODS AND RESULTS

A total of 711 university employees (48±11 years; 66% women, 72% Caucasian/22.5% African Americans) enrolled in a program that promoted healthier lifestyles at Emory University (Atlanta, GA). Anthropometric, laboratory, and physical activity measurements were performed at baseline and at 6 months, 1 year, and 2 years of follow-up. Results were utilized by the Health Partner to generate a personalized plan aimed at meeting ideal health metrics. Compared to baseline, at each of the 6-month, 1-year, and 2-year follow-up visits, systolic blood pressure was lower by 3.6, 4.6, and 3.3 mm Hg (P<0.001), total cholesterol decreased by 5.3, 6.5, and 6.4 mg/dL (P<0.001), body mass index declined by 0.33, 0.45, and 0.38 kg/m² (P<0.001), and the percentage of smokers decreased by 1.3%, 3.5%, and 3.5% (P<0.01), respectively. Changes were greater in those with greater abnormalities at baseline. Finally, the American Heart Association "Life's Simple 7" ideal cardiovascular health score increased by 0.28, 0.40, and 0.33 at 6 month, 1 year, and 2 years, respectively, compared to baseline visit.

CONCLUSIONS

A personalized, goal-directed Health Partner intervention significantly improved the cardiometabolic risk profile and metrics of cardiovascular health. These effects were evident at 6 months following enrollment and were sustained for 2 years. Whether the Health Partner intervention improves long-term morbidity and mortality and is cost-effective needs further investigation.

A Burden of Rare Variants Associated with Extremes of Gene Expression in Human Peripheral Blood

In order to evaluate whether rare regulatory variants in the vicinity of promoters are likely to impact gene expression, we conducted a novel burden test for enrichment of rare variants at the extremes of expression. After sequencing 2-kb promoter regions of 472 genes in 410 healthy adults, we performed a quadratic regression of rare variant count on bins of peripheral blood transcript abundance from microarrays, summing over ranks of all genes. After adjusting for common eQTLs and the major axes of gene expression covariance, a highly significant excess of variants with minor allele frequency less than 0.05 at both high and low extremes across individuals was observed. Further enrichment was seen in sites annotated as potentially regulatory by RegulomeDB, but a deficit of effects was associated with known metabolic disease genes. The main result replicates in an independent sample of 75 individuals with RNA-seq and whole-genome sequence information. Three of four predicted large-effect sites were validated by CRISPR/Cas9 knockdown in K562 cells, but simulations indicate that effect sizes need not be unusually large to produce the observed burden. Unusually divergent low-frequency promoter haplotypes were observed at 31 loci, at least 9 of which appear to be derived from Neandertal admixture, but these were not associated with divergent gene expression in blood. The overall burden test results are consistent with rare and private regulatory variants driving high or low transcription at specific loci, potentially contributing to disease.

PART of the WHOLE: A Case Study in Wellness-Oriented Personalized Medicine

We describe the Wellness and Health Omics Linked to the Environment (WHOLE) personalized medicine profile for a 50-year-old Caucasian male living in Atlanta, Georgia. Based on the principle that genomic medicine will be most effective when presented in the context of an individual's clinical and lifestyle data, we propose the use of a "risk radar" that summarizes health risks in eight domains. Rather than providing overwhelming lists of potentially deleterious genetic variants, we argue that profiles should be palatable, actionable, reproducible, and teachable: the PART principle. Genetic risk scores for this individual are strikingly concordant for his height, body mass index (BMI), waist hip ration (WHR), and cholesterol, and blood transcriptome data agrees with and complements his complete blood counts. Despite enjoying currently good health, his risk radar highlights metabolic disease as his major health concern.

Roles of Arterial Stiffness and Blood Pressure in Hypertension-Associated Cognitive Decline in Healthy Adults

Although there is strong evidence that hypertension leads to cognitive decline, especially in the executive domain, the relationship between blood pressure and cognition has been conflicted. Hypertension is characterized by blood pressure elevation and increased arterial stiffness. We aimed at investigating whether arterial stiffness would be superior to blood pressure in predicting cognitive decline and explaining the hypertension-executive decline association. A randomly selected asymptomatic population (n=591, age=49.2 years, 70% women, 27% black, and education=18 years) underwent annual vascular and cognitive assessments. Cognition was assessed using computerized versions commonly used cognitive tests, and principal component analysis was used for deriving cognitive scores for executive function, memory, and working memory. Arterial stiffness was measured by carotid-femoral pulse wave velocity (PWV). Higher PWV, but not blood pressure, was associated with a steeper decline in executive (P=0.0002), memory (P=0.05), and working memory (P=0.02) scores after adjusting for demographics, education, and baseline cognitive performance. This remained true after adjusting for hypertension. Hypertension was associated with greater decline in executive score (P=0.0029) and those with combined hypertension and elevated PWV (>7 m/s) had the greatest decline in executive score (P value hypertension×PWV=0.02). PWV explained the association between hypertension and executive function (P value for hypertension=0.0029 versus 0.24 when adjusting for PWV). In healthy adults, increased arterial stiffness is superior to blood pressure in predicting cognitive decline in all domains and in explaining the hypertension-executive function association. Arterial stiffness, especially in hypertension, may be a target in the prevention of cognitive decline.

Inflammation and cognitive functioning in African Americans and Caucasians

OBJECTIVE

To examine associations between inflammation and cognitive performance in African Americans and Caucasians.

METHODS

The sample included 59 African Americans and 219 Caucasians ≥  50 years old who had a baseline visit at the Emory/Georgia Tech Center for Health Discovery and Well Being. Peripheral levels of inflammation (interleukin-6, interleukin-8, C-reactive protein, and tumor necrosis factor-α) were examined in relation to performance on tests of visual processing (Identify the Odd Pattern), attention (Digit Span Forward), visuomotor set shifting (Digit Symbol Substitution), verbal set shifting (Digit Span Backwards), and memory (Recall a Pattern).

RESULTS

Multiple regression models adjusting for potential demographic and vascular/metabolic confounders were conducted, with markers of inflammation included as either continuous or categorical (quartiles) variables. There were significant interactions between IL-8 and race for the Recall a Pattern (p = .006) and the Digit Symbol Substitution (p = .014) tests. Race-specific analyses (using a continuous variable for IL-8) demonstrated slower response times on the Recall a Pattern and Digit Symbol Substitution tests for African Americans but not for Caucasians. Categorical analyses among African Americans indicated that all of the top three quartiles of IL-8 were associated with slower reaction times on the Recall a Pattern test compared to the lowest quartile, while for Digit Symbol, the highest quartile of IL-8 was associated with the slowest cognitive performance.

CONCLUSIONS

These preliminary findings suggest a stronger association between IL-8 and cognitive performance in African Americans than Caucasians. This relationship should be further examined in larger samples that are followed over time.

Omic personality: implications of stable transcript and methylation profiles for personalized medicine

Background

Personalized medicine is predicated on the notion that individual biochemical and genomic profiles are relatively constant in times of good health and to some extent predictive of disease or therapeutic response. We report a pilot study quantifying gene expression and methylation profile consistency over time, addressing the reasons for individual uniqueness, and its relation to N = 1 phenotypes.

Methods

Whole blood samples from four African American women, four Caucasian women, and four Caucasian men drawn from the Atlanta Center for Health Discovery and Well Being study at three successive 6-month intervals were profiled by RNA-Seq, miRNA-Seq, and Illumina Methylation 450 K arrays. Standard regression approaches were used to evaluate the proportion of variance for each type of omic measure among individuals, and to quantify correlations among measures and with clinical attributes related to wellness.

Results

Longitudinal omic profiles were in general highly consistent over time, with an average of 67 % variance in transcript abundance, 42 % in CpG methylation level (but 88 % for the most differentiated CpG per gene), and 50 % in miRNA abundance among individuals, which are all comparable to 74 % variance among individuals for 74 clinical traits. One third of the variance could be attributed to differential blood cell type abundance, which was also fairly stable over time, and a lesser amount to expression quantitative trait loci (eQTL) effects. Seven conserved axes of covariance that capture diverse aspects of immune function explained over half of the variance. These axes also explained a considerable proportion of individually extreme transcript abundance, namely approximately 100 genes that were significantly up-regulated or down-regulated in each person and were in some cases enriched for relevant gene activities that plausibly associate with clinical attributes. A similar fraction of genes had individually divergent methylation levels, but these did not overlap with the transcripts, and fewer than 20 % of genes had significantly correlated methylation and gene expression.

Conclusions

People express an “omic personality” consisting of peripheral blood transcriptional and epigenetic profiles that are constant over the course of a year and reflect various types of immune activity. Baseline genomic profiles can provide a window into the molecular basis of traits that might be useful for explaining medical conditions or guiding personalized health decisions.

Electronic supplementary material

The online version of this article (doi:10.1186/s13073-015-0209-4) contains supplementary material, which is available to authorized users.

Health Care Expenditures for University and Academic Medical Center Employees Enrolled in a Pilot Workplace Health Partner Intervention

OBJECTIVE

To evaluate the impact of a pilot workplace health partner intervention delivered by a predictive health institute to university and academic medical center employees on per-member, per-month health care expenditures.

METHODS

We analyzed the health care claims of participants versus nonparticipants, with a 12-month baseline and 24-month intervention period. Total per-member, per-month expenditures were analyzed using two-part regression models that controlled for sex, age, health benefit plan type, medical member months, and active employment months.

RESULTS

Our regression results found no statistical differences in total expenditures at baseline and intervention. Further sensitivity analyses controlling for high cost outliers, comorbidities, and propensity to be in the intervention group confirmed these findings.

CONCLUSIONS

We find no difference in health care expenditures attributable to the health partner intervention. The intervention does not seem to have raised expenditures in the short term.

Vitamin D deficiency is associated with anaemia among African Americans in a US cohort

Vitamin D deficiency is highly prevalent in the US population and is associated with numerous diseases, including those characterised by inflammatory processes. We aimed to investigate the link between vitamin D status and anaemia, hypothesising that lower vitamin D status would be associated with increased odds of anaemia, particularly anaemia with inflammation. A secondary aim was to examine the effects of race in the association between vitamin D status and anaemia. We conducted a cross-sectional analysis in a cohort of generally healthy adults in Atlanta, GA (n 638). Logistic regression was used to evaluate the association between vitamin D status and anaemia. Serum 25-hydroxyvitamin D (25(OH)D) < 50 nmol/l (compared to 25(OH)D ≥ 50 nmol/l) was associated with anaemia in bivariate analysis (OR 2·64, 95% CI 1·43, 4·86). There was significant effect modification by race (P= 0·003), such that blacks with 25(OH)D < 50 nmol/l had increased odds of anaemia (OR 6·42, 95% CI 1·88, 21·99), v. blacks with 25(OH)D ≥ 50 nmol/l, controlling for potential confounders; this association was not apparent in whites. When categorised by subtype of anaemia, blacks with 25(OH)D < 50 nmol/l had significantly increased odds of anaemia with inflammation than blacks with serum 25(OH)D ≥ 50 nmol/l (OR 8·42, 95% CI 1·96, 36·23); there was no association with anaemia without inflammation. In conclusion, serum 25(OH)D < 50 nmol/l was significantly associated with anaemia, particularly anaemia with inflammation, among blacks in a generally healthy adult US cohort.

A Longitudinal Study of Health Improvement in the Atlanta CHDWB Wellness Cohort

The Center for Health Discovery and Wellbeing (CHDWB) is an academic program designed to evaluate the efficacy of clinical self-knowledge and health partner counseling for development and maintenance of healthy behaviors. This paper reports on the change in health profiles for over 90 traits, measured in 382 participants over three visits in the 12 months following enrolment. Significant changes in the desired direction of improved health are observed for many traits related to cardiovascular health, including BMI, blood pressure, cholesterol, and arterial stiffness, as well as for summary measures of physical and mental health. The changes are most notable for individuals in the upper quartile of baseline risk, many of whom showed a positive correlated response across clinical categories. By contrast, individuals who start with more healthy profiles do not generally show significant improvements and only a modest impact of targeting specific health attributes was observed. Overall, the CHDWB model shows promise as an effective intervention particularly for individuals at high risk for cardiovascular disease.

Vitamin D status is independently associated with plasma glutathione and cysteine thiol/disulphide redox status in adults

OBJECTIVE

Redox status and inflammation are important in the pathophysiology of numerous chronic diseases. Epidemiological studies have linked vitamin D status to a number of chronic diseases. We aimed to examine the relationships between serum 25-hydroxyvitamin D [25(OH)D] and circulating thiol/disulphide redox status and biomarkers of inflammation.

DESIGN

This was a cross-sectional study of N = 693 adults (449 females, 244 males) in an apparently healthy, working cohort in Atlanta, GA. Plasma glutathione (GSH), cysteine (Cys) and their associated disulphides were determined with high-performance liquid chromatography, and their redox potentials (Eh GSSG and Eh CySS) were calculated using the Nernst equation. Serum inflammatory markers included interleukin-6 (IL-6), interleukin-8 (IL-8) and tumour necrosis factor-α, assayed on a multiplex platform, and C-reactive protein (CRP), assayed commercially. Relationships were assessed with multiple linear regression analyses.

RESULTS

Serum 25(OH)D was positively associated with plasma GSH (β ± SE: 0·002 ± 0·0004) and negatively associated with plasma Eh GSSG (β ± SE: -0·06 ± 0·01) and Cys (β ± SE: -0·01 ± 0·003) (P < 0·001 for all); statistical significance remained after adjusting for age, gender, race, percentage body fat and traditional cardiovascular risk factors (P = 0·01-0·02). The inverse relationship between serum 25(OH)D and CRP was confounded by percentage body fat, and full adjustment for covariates attenuated serum 25(OH)D relationships with other inflammatory markers to nonstatistical significance.

CONCLUSIONS

Serum 25(OH)D concentrations were independently associated with major plasma thiol/disulphide redox systems, suggesting that vitamin D status may be involved in redox-mediated pathophysiology.

Engaging young adults in proactive health behaviors: a goal-setting process

The Human Health Program at Emory University, Atlanta, Georgia, is an undergraduate curriculum that focuses on health in its broadest context, exploring novel strategies that educate, engage, empower, and encourage college students to develop and sustain healthy lifestyle behaviors. In the program, students take part in a onesemester experience that is a blend of academic health education and wellness coaching, where the group class supports a self-directed health goal process.

Wellness and health omics linked to the environment: the WHOLE approach to personalized medicine

The WHOLE approach to personalized medicine represents an effort to integrate clinical and genomic profiling jointly into preventative health care and the promotion of wellness. Our premise is that genotypes alone are insufficient to predict health outcomes, since they fail to account for individualized responses to the environment and life history. Instead, integrative genomic approaches incorporating whole genome sequences and transcriptome and epigenome profiles, all combined with extensive clinical data obtained at annual health evaluations, have the potential to provide more informative wellness classification. As with traditional medicine where the physician interprets subclinical signs in light of the person's health history, truly personalized medicine will be founded on algorithms that extract relevant information from genomes but will also require interpretation in light of the triggers, behaviors, and environment that are unique to each person. This chapter discusses some of the major obstacles to implementation, from development of risk scores through integration of diverse omic data types to presentation of results in a format that fosters development of personal health action plans.

Human interaction with policy flight simulators

Policy flight simulators are designed for the purpose of exploring alternative management policies at levels ranging from individual organizations to national strategy. This article focuses on how such simulators are developed and on the nature of how people interact with these simulators. These interactions almost always involve groups of people rather than individuals, often with different stakeholders in conflict about priorities and courses of action. The ways in which these interactions are framed and conducted are discussed, as well as the nature of typical results.

Whole genome sequencing in support of wellness and health maintenance

Background

Whole genome sequencing is poised to revolutionize personalized medicine, providing the capacity to classify individuals into risk categories for a wide range of diseases. Here we begin to explore how whole genome sequencing (WGS) might be incorporated alongside traditional clinical evaluation as a part of preventive medicine. The present study illustrates novel approaches for integrating genotypic and clinical information for assessment of generalized health risks and to assist individuals in the promotion of wellness and maintenance of good health.

Methods

Whole genome sequences and longitudinal clinical profiles are described for eight middle-aged Caucasian participants (four men and four women) from the Center for Health Discovery and Well Being (CHDWB) at Emory University in Atlanta. We report multivariate genotypic risk assessments derived from common variants reported by genome-wide association studies (GWAS), as well as clinical measures in the domains of immune, metabolic, cardiovascular, musculoskeletal, respiratory, and mental health.

Results

Polygenic risk is assessed for each participant for over 100 diseases and reported relative to baseline population prevalence. Two approaches for combining clinical and genetic profiles for the purposes of health assessment are then presented. First we propose conditioning individual disease risk assessments on observed clinical status for type 2 diabetes, coronary artery disease, hypertriglyceridemia and hypertension, and obesity. An approximate 2:1 ratio of concordance between genetic prediction and observed sub-clinical disease is observed. Subsequently, we show how more holistic combination of genetic, clinical and family history data can be achieved by visualizing risk in eight sub-classes of disease. Having identified where their profiles are broadly concordant or discordant, an individual can focus on individual clinical results or genotypes as they develop personalized health action plans in consultation with a health partner or coach.

Conclusion

The CHDWB will facilitate longitudinal evaluation of wellness-focused medical care based on comprehensive self-knowledge of medical risks.

High-performance metabolic profiling with dual chromatography-Fourier-transform mass spectrometry (DC-FTMS) for study of the exposome

Studies of gene-environment (G × E) interactions require effective characterization of all environmental exposures from conception to death, termed the exposome. The exposome includes environmental exposures that impact health. Improved metabolic profiling methods are needed to characterize these exposures for use in personalized medicine. In the present study, we compared the analytic capability of dual chromatography-Fourier-transform mass spectrometry (DC-FTMS) to previously used liquid chromatography-FTMS (LC-FTMS) analysis for high-throughput, top-down metabolic profiling. For DC-FTMS, we combined data from sequential LC-FTMS analyses using reverse phase (C18) chromatography and anion exchange (AE) chromatography. Each analysis was performed with electrospray ionization in the positive ion mode and detection from m/z 85 to 850. Run time for each column was 10 min with gradient elution; 10 µl extracts of plasma from humans and common marmosets were used for analysis. In comparison to analysis with the AE column alone, addition of the second LC-FTMS analysis with the C18 column increased m/z feature detection by 23-36%, yielding a total number of features up to 7,000 for individual samples. Approximately 50% of the m/z matched to known chemicals in metabolomic databases, and 23% of the m/z were common to analyses on both columns. Database matches included insecticides, herbicides, flame retardants, and plasticizers. Modularity clustering algorithms applied to MS-data showed the ability to detection clusters and ion interactions. DC-FTMS thus provides improved capability for high-performance metabolic profiling of the exposome and development of personalized medicine.

Integrating comparative effectiveness research programs into predictive health: a unique role for academic health centers

The growing burden of chronic disease, an aging population, and rising health care costs threaten the sustainability of our current model for health care delivery. At the same time, innovations in predictive health offer a pathway to reduce disease burden by preventing and mitigating the development of disease. Academic health centers are uniquely positioned to evaluate the comparative effectiveness of predictive and personalized health interventions, given institutional core competencies in innovative knowledge development. The authors describe Emory University's commitment to integrating comparative effectiveness research (CER) into predictive health programs through the creation and concurrent evaluation of its Center for Health Discovery and Well Being (hereafter, "the Center"). Established in 2008, the Center is a clinical laboratory for testing the validity and utility of a health-focused rather than disease-focused care setting. The Center provides preventive health services based on the current evidence base, evaluates the effectiveness of its care delivery model, involves trainees in both the delivery and evaluation of its services, and collects structured physical, social, and emotional health data on all participants over time. Concurrent evaluation allows the prospective exploration of the complex interactions among health determinants as well as the comparative effectiveness of novel biomarkers in predicting health. Central to the Center is a cohort study of randomly selected university employees. The authors describe how the Center has fostered a foundation for CER through the structured recruitment of study cohorts, standardized interventions, and scheduled data collection strategies that support pilot studies by faculty and trainees.