Large Healthy Cohort Research Articles

Simultaneous measurement of kynurenine metabolites and explorative metabolomics using liquid chromatography-mass spectrometry: A novel accurate method applied to serum and plasma samples from a large healthy cohort

Kynurenine metabolites are emerging as promising clinical biomarkers in several diseases, especially within psychiatry. Unfortunately, they are difficult to detect, particularly the challenging neurotoxic metabolite quinolinic acid (QUIN). The aim of this study was twofold: First, to develop a liquid chromatography-mass spectrometry method (LC-MS) for simultaneous targeted quantification of key kynurenine metabolites together with untargeted metabolomics, and second, to demonstrate the feasibility of the method by exploring serum/plasma and gender differences in 120 healthy young adults between 18 and 30 years of age. A range of analytical columns (C18 and biphenyl columns) and mobile phases (acidic and alkaline) were systematically evaluated. The optimized LC-MS method was based on a biphenyl column, a water-methanol gradient with 0.2% formic acid, and authentic isotope-labeled standards for each kynurenine metabolite. Precision and accuracy of targeted quantification of the key kynurenine metabolites tryptophan (TRP), kynurenine (KYN), kynurenic acid (KYNA), 3-hydroxykynurenine (3-HK), and QUIN were excellent, far exceeding the acceptance criteria specified by international guidelines. Median inter- and intra-day precision were < 6% in serum and plasma; the median accuracy was 2.4% in serum and 8% in plasma. Serum concentrations were ≤ 10% different from the corresponding concentrations in plasma for all kynurenine metabolites in healthy young adults. Men had higher levels (8–18%) of TRP, KYN, and KYNA than women (p ≤ 0.009), while no differences were observed for 3-HK and QUIN (p > 0.70). Incurred sample reanalysis of 10% of the samples yielded a median difference < 5% from the initial measurement, demonstrating the robustness of the method. Besides the targeted quantification of key kynurenine metabolites, our method was found to be suitable for simultaneous untargeted metabolomics analyses of hundreds of metabolites. A range of compound classes could be detected including amino acids, nucleic acids, dipeptides, antioxidants, and acylcarnitines, making explorative studies highly feasible. For example, we identified an additional kynurenine metabolite, 2-Quinolinecarboxylic acid, which was 47% higher in males than females (adjusted p-value = 0.001). In conclusion, in this study, we present a reliable and robust LC-MS method for simultaneous targeted and untargeted metabolomics ready for both research and clinical use. We show that both serum and plasma can be used for kynurenine studies, and the reported gender differences are in accordance with the literature. Future studies should consider using biphenyl-based LC-MS columns to successfully detect QUIN.

Density and distribution of dendritiform cells in the peripheral cornea of healthy subjects using in vivo confocal microscopy

PurposeTo establish in a large healthy cohort, dendritiform cell (DC) density and morphological parameters in the central and peripheral cornea using in vivo confocal microscopy (IVCM). MethodsA prospective, cross-sectional, observational study was conducted in 85 healthy volunteers (n = 85 eyes). IVCM images of corneal center and four peripheral zones were analyzed for DC density and morphology to compare means and assess correlations (p < 0.05 being statistically significant). ResultsCentral corneas had lower DC density (40.83 ± 5.14 cells/mm2; mean ± SEM) as compared to peripheral corneas (75.42 ± 2.67 cells/mm2, p < 0.0001). Inferior and superior zones demonstrated higher DC density (105.01 ± 7.12 and 90.62 ± 4.62 cells/mm2) compared to the nasal and temporal zones (59.93 ± 3.42 and 51.77 ± 2.98 cells/mm2, p < 0.0001). Similarly, lower DC size, field and number of dendrites were observed in the central as compared to the average peripheral cornea (p < 0.0001), with highest values in the inferior zone (p < 0.001 for all, except p < 0.05 for number of dendrites in superior zone). DC parameters did not correlate with age or gender. Inter-observer reliability was 0.987 for DC density and 0.771–0.922 for morphology. ConclusionIn healthy individuals, the peripheral cornea demonstrates higher DC density and larger morphology compared to the center, with highest values in the inferior zone. We provide the largest normative cohort for sub-stratified DC density and morphology, which can be used in future clinical trials to compare differential changes in diseased states. Furthermore, as DC parameters in the peripheral zones are dissimilar, random sampling of peripheral cornea may be inaccurate.

Dorsal Root Ganglion Volumetry by MR Gangliography.

Dorsal root ganglion MR imaging (MR gangliography) is increasingly gaining clinical-scientific relevance. However, dorsal root ganglion morphometry by MR imaging is typically performed under the assumption of ellipsoid geometry, which remains to be validated. Sixty-four healthy volunteers (37 [57.8%] men; mean age, 31.5 [SD, 8.3] years) underwent MR gangliography of the bilateral L4-S2 levels (3D-T2WI TSE spectral attenuated inversion recovery-sampling perfection with application-optimized contrasts by using different flip angle evolution, isotropic voxels = 1.1 mm³, TE = 301 ms). Ground truth dorsal root ganglion volumes were bilaterally determined for 96 dorsal root ganglia (derivation cohort) by expert manual 3D segmentation by 3 independent raters. These ground truth dorsal root ganglion volumes were then compared with geometric ellipsoid dorsal root ganglion approximations as commonly practiced for dorsal root ganglion morphometry. On the basis of the deviations from ellipsoid geometry, improved volume estimation could be derived and was finally applied to a large human validation cohort (510 dorsal root ganglia). Commonly used equations of ellipsoid geometry underestimate true dorsal root ganglion volume by large degrees (factor = 0.42-0.63). Ground truth segmentation enabled substantially optimizing dorsal root ganglion geometric approximation using its principal axes lengths by deriving the dorsal root ganglion volume term of [Formula: see text]. Using this optimization, the mean volumes of 510 lumbosacral healthy dorsal root ganglia were as follows: L4: 211.3 (SD, 52.5) mm³, L5: 290.7 (SD, 90.9) mm³, S1: 384.2 (SD, 145.0) mm³, and S2: 192.4 (SD, 52.6) mm³. Dorsal root ganglion volume increased from L4 to S1 and decreased from S1 to S2 (P < .001). Dorsal root ganglion volume correlated with subject height (r = . 22, P < .001) and was higher in men (P < .001). Dorsal root ganglion volumetry by measuring its principal geometric axes on MR gangliography can be substantially optimized. By means of this optimization, dorsal root ganglion volume distribution was estimated in a large healthy cohort for the clinically most relevant lumbosacral levels, L4-S2.

Abstract 045: Adolescent Arterial Stiffness Precedes Elevated Resting Heart Rate In Young Adulthood: A 7-year Temporal Longitudinal Analysis Using Cross-lagged Structural Equation Model

Introduction: Elevated resting heart rate in adults is an established risk factor in the lifelong process of atherogenesis and its intermediate process such as arterial stiffness. Arterial stiffness is an independent predictor of cardiovascular events. However, it is unclear whether resting heart rate temporally and bi-directionally associates with arterial stiffness especially among healthy adolescents and young adults. Hence, plausible biologic pathways through which elevated resting heart rate associate with arterial stiffness in the young population remains unknown. Hypothesis: To examine the temporal longitudinal associations of carotid-femoral pulse wave velocity (cfPWV), a measure of arterial stiffness, with resting heart rate among adolescents aged 17.7 years. Methods: We studied 3862 (55.5% female) British adolescents followed up for 7 years until 24.5 years of age, using data from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort, England, UK. At baseline and follow-up, fat mass and lean mass were measured by dual-energy Xray absorptiometry, systolic blood pressure and heart rate by Omron BP/pulse monitor, and cfPWV by Vicorder ultrasound scan. We conducted logistic regression and cross-lagged autoregressive structural equation model analyses and adjusted for age at baseline, sex, moderate to vigorous physical activity, smoking status, family history of cardiometabolic diseases, time in years between measurement at 17.7 and 24.5 years, systolic blood pressure, fat mass, lean mass, and fasting plasma samples viz. low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride, high-sensitivity C-reactive protein, glucose, and insulin. Results: Participants' mean (SD) age in years was 17.72 (0.33) and 24.54 (0.73) at baseline and follow-up, respectively. Among 3862 adolescents, 10% were at moderate to high risk of elevated resting heart rate at 24.5 years. Higher cfPWV at 17.7 years was associated with the risk of elevated resting heart rate at follow-up [ Odds ratio = 1.32 (95% confidence interval 1.06 - 1.65); p=0.014]. In the cross-lagged temporal analysis, higher cfPWV at 17.7 years was associated with higher resting heart rate [ Standardized regression coefficient (β) = 0.06 standard error (SE) = 3.85, p&lt;0.0001] at 24.5 years, however, higher resting heart rate at 17.7 years was not associated with cfPWV [β = -0.03, SE &lt;0.0001, p=0.179] at 24.5 years. Conclusion: We observed, for the first time, in a large healthy cohort of adolescents that arterial stiffness temporally preceded elevated resting heart rate in young adulthood, after controlling for cardiometabolic and lifestyle factors. This evidence informs that public health and clinical effort may be targeted at early detection and prevention of arterial stiffness from adolescence.

Abstract EP70: Adolescent Arterial Stiffness Precedes Elevated Resting Heart Rate In Young Adulthood: A 7-year Temporal Longitudinal Analysis Using Cross-lagged Structural Equation Model

Introduction: Elevated resting heart rate in adults is an established risk factor in the lifelong process of atherogenesis and its intermediate process such as arterial stiffness. Arterial stiffness is an independent predictor of cardiovascular events. However, it is unclear whether resting heart rate temporally and bi-directionally associates with arterial stiffness especially among healthy adolescents and young adults. Hence, plausible biologic pathways through which elevated resting heart rate associate with arterial stiffness in the young population remains unknown. Hypothesis: To examine the temporal longitudinal associations of carotid-femoral pulse wave velocity (cfPWV), a measure of arterial stiffness, with resting heart rate among adolescents aged 17.7 years. Methods: We studied 3862 (55.5% female) British adolescents followed up for 7 years until 24.5 years of age, using data from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort, England, UK. At baseline and follow-up, fat mass and lean mass were measured by dual-energy Xray absorptiometry, systolic blood pressure and heart rate by Omron BP/pulse monitor, and cfPWV by Vicorder ultrasound scan. We conducted logistic regression and cross-lagged autoregressive structural equation model analyses and adjusted for age at baseline, sex, moderate to vigorous physical activity, smoking status, family history of cardiometabolic diseases, time in years between measurement at 17.7 and 24.5 years, systolic blood pressure, fat mass, lean mass, and fasting plasma samples viz. low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride, high-sensitivity C-reactive protein, glucose, and insulin. Results: Participants' mean (SD) age in years was 17.72 (0.33) and 24.54 (0.73) at baseline and follow-up, respectively. Among 3862 adolescents, 10% were at moderate to high risk of elevated resting heart rate at 24.5 years. Higher cfPWV at 17.7 years was associated with the risk of elevated resting heart rate at follow-up [ Odds ratio = 1.32 (95% confidence interval 1.06 - 1.65); p=0.014]. In the cross-lagged temporal analysis, higher cfPWV at 17.7 years was associated with higher resting heart rate [ Standardized regression coefficient (β) = 0.06 standard error (SE) = 3.85, p&lt;0.0001] at 24.5 years, however, higher resting heart rate at 17.7 years was not associated with cfPWV [β = -0.03, SE &lt;0.0001, p=0.179] at 24.5 years. Conclusion: We observed, for the first time, in a large healthy cohort of adolescents that arterial stiffness temporally preceded elevated resting heart rate in young adulthood, after controlling for cardiometabolic and lifestyle factors. This evidence informs that public health and clinical effort may be targeted at early detection and prevention of arterial stiffness from adolescence.

Replicable brain signatures of emotional bias and memory based on diffusion kurtosis imaging of white matter tracts.

Diffusion MRI (dMRI) is sensitive to anisotropic diffusion within bundles of nerve axons and can be used to make objective measurements of brain networks. Many brain disorders are now recognised as being caused by network dysfunction or are secondarily associated with changes in networks. There is therefore great potential in using dMRI measures that reflect network integrity as a future clinical tool to help manage these conditions. Here, we used dMRI to identify replicable, robust and objective markers that meaningfully reflect cognitive and emotional performance. Using diffusion kurtosis analysis and a battery of cognitive and emotional tests, we demonstrated strong relationships between white matter structure across networks of anatomically and functionally specific brain regions with both emotional bias and emotional memory performance in a large healthy cohort. When the connectivity of these regions was examined using diffusion tractography, the terminations of the identified tracts overlapped precisely with cortical loci relating to these domains, drawn from an independent spatial meta‐analysis of available functional neuroimaging literature. The association with emotional bias was then replicated using an independently acquired healthy cohort drawn from the Human Connectome Project. These results demonstrate that, even in healthy individuals, white matter dMRI structural features underpin important cognitive and emotional functions. Our robust cross‐correlation and replication supports the potential of structural brain biomarkers from diffusion kurtosis MRI to characterise early neurological changes and risk in individuals with a reduced threshold for cognitive dysfunction, with further testing required to demonstrate clinical utility.

Biological variation of resting measures of ventilation and gas exchange in a large healthy cohort.

Resting measures of ventilation and gas exchange are impacted by a variety of physiological stressors, such as those resulting from a research intervention or an extreme environment. However, the biological variation of these parameters, an important statistical consideration for identifying a meaningful physiological change, has not been quantified. We performed a retrospective analysis of 21 studies completed by the U.S. Army Research Institute of Environmental Medicine (USARIEM) from 1985 to present, totaling 411 healthy volunteers. First, we determined the intraindividual, interindividual, and analytic coefficients of variation (CVI, CVG, and CVA, respectively) and subsequently the index of individuality and heterogeneity (II and IH, respectively). Second, when deemed appropriate via these outcomes, we defined the accompanying static and dynamic thresholds, beyond which a significant deviation from normal is indicated. End-tidal partial pressure of oxygen (PETO2) and the respiratory exchange ratio (RER) approached the II threshold required to be considered useful in the static assessment of physiological deviations from normal. PETO2 and peripheral oxygen saturation (SpO2) approached the IH threshold required to be considered useful in the dynamic assessment of physiological deviations from normal. This analysis identifies RER and PETO2 as parameters that might be most useful when aiming to identify a meaningful ventilatory change following a research intervention or stressor. Alternatively, other parameters of ventilation and gas exchange, such as PETCO2 and VE, may be less useful for observing an anticipated physiological change.

MON-615 Seasonal Changes in Thyroid Function in Healthy Subjects in Japan: Analysis of 8,489 Health Check Participants

Aim: Thyroid hormone affects the whole-body metabolism, including that of lipids and glucose, and its involvement in NAFLD / NASH has recently been reported. Accurate evaluation of thyroid function is therefore important. In this study, seasonal changes in thyroid function in approximately 10,000 health check participants were investigated, and the effects of age and smoking were also examined.Subjects and methods: The subjects were participants of medical checkups at Hidaka Hospital from 2007 to 2013. Exclusion criteria were a past history of thyroid disease, steroid use, renal failure and liver cirrhosis. To exclude the effects of menstruation, we examined 8,489 men whose blood TSH and FT4 values were within the reference values for monthly changes in thyroid function, and the effects of age and smoking. All blood TSH and FT4 levels were measured at 8 ~ 9:00 AM after over night fasting.Results: The average age was 49 ± 10 years old. The number of participants varied each month, with a minimum of 346 in April and a maximum of 961 in November. The highest median serum TSH level was 1.6 μU/ml in January (winter), and the lowest was 1.3 μU/ml in June, July, August and September (summer). These values were significantly different from the yearly median value of 1.4 μU/ml in April and November. On the other hand, the FT4 level was significantly lower in August than in the other months except for February. The extents of seasonal changes in TSH and FT4 levels were reduced in elderly subjects >60 years old. Furthermore, the median blood TSH level of 2,262 smokers was lower than that of 4,709 non-smokers (median: smoker, 1.2μU/ml vs. non-smoker, 1.5μU/ml). However, seasonal changes were also observed in smokers. Conclusions: This is the first report in a large healthy cohort demonstrating that there are significant seasonal changes in thyroid function including freeT4 levels. Several factors, such as season, age, smoking and gender, need to be taken into account for accurate evaluation of thyroid function.

Brain structural correlates of irritability: Findings in a large healthy cohort.

Irritability and nonviolent aggression are common behavioral features across the population, yet there is limited neurobiological research into subclinical phenotypes representing the lower edge of a symptom continuum ranging from slight irritability to criminal violence. We studied brain structural correlates of irritability in a large healthy cohort to test the hypothesis of associations with fronto-limbic brain structures implicated in mood regulation. In a large multicenter effort, we recruited 409 mentally healthy adults from the community, who received T1-weighted high-resolution 3T MRI scans. These structural scans were automatically preprocessed for voxel- and surface-based morphometry measurements with the CAT 12 toolbox implemented in SPM 12. Subclinical aggressive symptoms were assessed using the SCL-90-R aggression/hostility subscale and then correlated with cortical volume (VBM), and cortical thickness and gyrification. VBM analysis showed significant (P < 0.05, FDR-corrected at peak-level) positive correlations of cortical volume with SCL-90-R aggression subscale values in large clusters spanning bilateral anterior cingulate and orbitofrontal cortices and left lingual and postcentral gyri. Surface-based morphometry yielded mostly uncorrected positive correlations with cortical thickness in bilateral precentral gyri and with gyrification in left insula and superior temporal gyrus. Our findings imply an association of subclinical aggressive symptoms with cortical volume in areas important for emotion awareness and regulation, which might also be related to cortical adaptation to mental stress. These results overlap with several findings on impulsive aggression in patients suffering from affective and disruptive behavior disorders. They also suggest a biological symptom continuum manifesting in these brain areas. Hum Brain Mapp 38:6230-6238, 2017. © 2017 Wiley Periodicals, Inc.

Interindividual Variability and Normal Ranges of Whole Blood and Plasma Thrombin Generation.

Assays measuring thrombin generation (TG) in plasma increasingly gained attention in the field of thrombosis and hemostasis. Adaptation of the method enabled the measurement of TG in whole blood (WB). Despite their potential, TG assays did not reach the stage of universal clinical application, partly because of the absence of normal ranges. Our study aimed to accurately determine normal ranges and interindividual variability of TG and correlate results with coagulation factor levels, sex, and oral contraceptive usage. The study protocol was evaluated by the local medical ethical board. In total, 129 healthy volunteers gave full informed consent. Normal ranges of TG in platelet-poor plasma (PPP), platelet-rich plasma (PRP), and WB were determined according to CLSI guidelines. Our study is the first to measure normal ranges of TG in PPP, PRP, and WB in a large healthy cohort. Significant correlations were found between TG in plasma and WB. Interindividual variability of TG in WB was comparable to that of plasma. Oral contraceptive use increased TG in PPP, PRP, and WB. The inhibitory effect of thrombomodulin on TG was significantly lower in females than in males. This effect was more pronounced upon oral contraceptive use. Primary clotting factor determinants for TG parameters depended on the tissue factor concentration, but were similar in WB and plasma. Establishing normal ranges for TG brings us 1 step closer to clinical use. Good correlations between plasma and WB (including clotting factor determinants for TG) suggest that WB TG can be reliably used in clinic.

Pediatric reference intervals for 29 Ortho VITROS 5600 immunoassays using the CALIPER cohort of healthy children and adolescents.

Accurate reference intervals (RIs) based on a healthy pediatric population are essential for pediatric test result interpretation. The CALIPER project has recruited a large healthy cohort and completed a series of a priori studies to address gaps in pediatric RIs. As immunoassays from different manufacturers for endocrine and special chemistry markers are not standardized and show marked intermethod differences, direct RI studies are needed for each major analytical platform. Here, we report age- and sex-specific pediatric RIs for 29 immunoassays on the Ortho Clinical Diagnostics (Ortho) VITROS® 5600 analyzer. Health information and blood samples were collected from healthy pediatric subjects. Using the Ortho VITROS 5600 Integrated System MicroWell Technology, 29 biomarkers were measured. Analyte concentrations were partitioned by age and sex according to the Harris and Boyd method. After removing outliers, age- and sex-specific RIs and corresponding 90% confidence intervals were calculated according to CLSI guidelines. All analytes required age partitioning except β-human chorionic gonadotropin (β-hCG), cancer antigen 15-3 (CA15-3), rubella immunoglobulin G (rubella IgG), and vitamin D. Several analytes including estradiol, progesterone, testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), free triiodothyronine (FT3), total triiodothyronine (TT3), total thyroxine (TT4), thyroid uptake, ferritin, intact parathyroid hormone (iPTH), total prostate-specific antigen (tPSA), free prostate-specific antigen (fPSA), cancer antigen 125 (CA125), creatine kinase MB (CK-MB), and myoglobin showed sex differences, observed mostly with the onset of puberty. Complex reference value trends were observed across the pediatric age range for several biomarkers examined on Ortho VITROS immunoassays. The availability of VITROS immunoassay RIs will enable accurate laboratory test interpretation and diagnosis for the pediatric population. As recommended by the CLSI EP28-A3c guidelines, implementation of these RIs should be validated for each laboratory's local pediatric population.

Association of host genome with intestinal microbial composition in a large healthy cohort.

Intestinal microbiota is known to be important in health and disease. Its composition is influenced by both environmental and host factors. Few large-scale studies have evaluated the association between host genetic variation and the composition of microbiota. We recruited a cohort of 1,561 healthy individuals, of whom 270 belong in 123 families, and found that almost one-third of fecal bacterial taxa were heritable. In addition, we identified 58 SNPs associated with the relative abundance of 33 taxa in 1,098 discovery subjects. Among these, four loci were replicated in a second cohort of 463 subjects: rs62171178 (nearest gene UBR3) associated with Rikenellaceae, rs1394174 (CNTN6) associated with Faecalibacterium, rs59846192 (DMRTB1) associated with Lachnospira, and rs28473221 (SALL3) associated with Eubacterium. After correction for multiple testing, 6 of the 58 associations remained significant, one of which replicated. These results identify associations between specific genetic variants and the gut microbiome.

Understanding Heterogeneity in Clinical Cohorts Using Normative Models: Beyond Case-Control Studies

BackgroundDespite many successes, the case-control approach is problematic in biomedical science. It introduces an artificial symmetry whereby all clinical groups (e.g., patients and control subjects) are assumed to be well defined, when biologically they are often highly heterogeneous. By definition, it also precludes inference over the validity of the diagnostic labels. In response, the National Institute of Mental Health Research Domain Criteria proposes to map relationships between symptom dimensions and broad behavioral and biological domains, cutting across diagnostic categories. However, to date, Research Domain Criteria have prompted few methods to meaningfully stratify clinical cohorts. MethodsWe introduce normative modeling for parsing heterogeneity in clinical cohorts, while allowing predictions at an individual subject level. This approach aims to map variation within the cohort and is distinct from, and complementary to, existing approaches that address heterogeneity by employing clustering techniques to fractionate cohorts. To demonstrate this approach, we mapped the relationship between trait impulsivity and reward-related brain activity in a large healthy cohort (N = 491). ResultsWe identify participants who are outliers within this distribution and show that the degree of deviation (outlier magnitude) relates to specific attention-deficit/hyperactivity disorder symptoms (hyperactivity, but not inattention) on the basis of individualized patterns of abnormality. ConclusionsNormative modeling provides a natural framework to study disorders at the individual participant level without dichotomizing the cohort. Instead, disease can be considered as an extreme of the normal range or as—possibly idiosyncratic—deviation from normal functioning. It also enables inferences over the degree to which behavioral variables, including diagnostic labels, map onto biology.

Abstract 15578: Adiposity, Systolic Blood Pressure, Smoking and Atrial Fibrillation: Analyses of 2.3 Million US Adults Attending Cardiovascular Screening

Aims: Unlike other vascular conditions, and for reasons that are incompletely understood, the prevalence of atrial fibrillation (AF) is rising sharply. Analysis of a large healthy cohort which was screened for AF allows reliable assessment of its association with several classical vascular risk factors. Methods: Between 2009 and 2013, around 3 million US adults attended cardiovascular screening clinics and had an ECG to identify AF. Personal and family medical history, medication use, smoking and alcohol consumption were recorded via questionnaires, and height, weight and blood pressure were measured. Age and gender-specific incidence of AF and associations between body mass index (BMI), systolic blood pressure (SBP) and smoking were measured in 2,320,190 participants with no reported prior history of AF, stroke or CHD. Results: The median age was 65, and two-thirds were female. The overall incidence of AF was 0.36%, but it was over twice as common in males (0.59%) than in females (0.23%) and rose sharply with age, doubling in each decade in both men and women. A positive association was seen between adiposity and AF in men and women across all ages studied: approximately 50% increase per 5 unit rise in BMI. By contrast, AF was only weakly associated with SBP - 10% increase per 10mmHg rise in SBP among participants aged under 70 years, and flat or even inversely associated among those over 70 years. Smoking was not associated with AF in men or women at any age (Odds Ratio for current vs never smokers = 0.97 [95% CI 0.79-1.19]). Conclusion: A 10 unit increase in BMI (ie, going from an “ideal” weight to “obese”) doubled the risk of AF. However, blood pressure was less strongly associated with AF, and only in those under 70 years, suggesting some other mechanism behind the BMI - AF association. Current smoking was not associated with AF. Rising rates of obesity may be driving the observed increase in AF in the developed world.

The 9p21.3 Locus

A series of reports in 2007 established that single nucleotide polymorphisms (SNPs) in the 9p21.3 locus are associated with coronary heart disease (CHD), both in patients with acute myocardial infarction and chronic atherosclerosis.1,–,4 Subsequently, many additional studies used a candidate locus approach to replicate the 9p21.3-CHD association. Intriguingly, other phenotypes have also been found to be associated with this genomic region, including type II diabetes, stroke, malignant melanoma, aortic aneurysms, cerebral aneurysms, and periodontitis. Unfortunately, neither the causative variants nor genes have been established. Although genetic associations may permit better disease risk stratification, without the knowledge of the genes and variants we lose opportunities to improve our basic understanding of the disease process and hence the potential for targeted therapies. Article see p 445 Many cellular pathways in multiple tissues contribute to the pathogenic processes resulting in CHD. There is value in using intermediate phenotypes as outcomes in genetic association studies because there is enhanced power to detect gene associations when the number of genes potentially responsible for the phenotype is reduced, thereby increasing the fraction of the variance explained by any single factor or gene. In addition, intermediate traits are usually easier to define (have less heterogeneity) than clinical disease. Somewhat surprisingly, 9p21.3 has not been associated with measures believed to represent the chronic process of atherosclerosis or endothelial cell reactivity,5 suggesting that this locus may contribute to CHD by an alternate pathophysiologic mechanism. There is abundant pathological and clinical evidence demonstrating the vital role played by blood platelets in acute coronary syndromes, which result from the formation of occlusive platelet thrombi in coronary arteries at the sites of ruptured atherosclerotic plaques,6,7 and antiplatelet agents have become a mainstay of therapy in patients with acute coronary syndromes. In addition to …

Abstract B135: Mortality risks and life-shortening effect of hepatitis C virus infection: A prospective cohort study of 487,369 adults in Taiwan

Abstract Background: There has been emerging knowledge on the serious burden of diseases attributable to Hepatitis C carriers (HCV). However, the extent of the life time risk of HCV, when independently assessed, is as yet fully understood, particularly regarding associated risk factors that are amenable to reductions. Objectives: We assessed the mortality risks and life-shortening effect of HCV, along with its associated risk factors, based on following up a large healthy cohort in Taiwan. Methods: The cohort, consisting of 487,369 subjects, participated in a standardized medical screening program since 1994. Based on the hepatitis carrier status (either HBV or HCV or both), three sub-cohorts were created. As of 2007, 16,920 deaths were identified, including 1,383 liver cancer and 631 cirrhosis, with average follow up of 8.5 years. Hazard ratio (RR) was calculated using Cox proportionate hazard model. National prevalence was arrived at by standardizing age and educational status, a surrogate for socioeconomic status (SES) to those in Taiwan. Glomerular Filtration Rate (GFR) was calculated by MDRD equation. Results: National Prevalence for HCV: 3.6% above age 20, and 6.6% above age 40 (male 6.0% and female 7.3%) increased with age and with lower SES. Rates of diabetes, hypertension, obesity, and HDL among HCV+ participants were significantly higher, but total cholesterol and triglycerides were lower. They had 35% more chronic kidney disease (CKD), with 54% more proteinuria and 13% more reduced GFR (13%). Cohort mortality results: HCV+ male participants had 7.37 years shorter than the total cohort at age 20, compared to 3.36 years for HBV+. In contrast to one out of 7 deaths (13.7%) in the total cohort was liver related, one out of two in the HCV+ sub-cohort. With HR for all-cause being 2.42, 58.7% of the deaths were HCV-related, larger than HBV counterparts (36.7%). The number of HCV related cirrhosis was 1/4 (28%) that of HCC, and HCV related risk, 10.74, was slightly smaller than that for HCC, 14.56. Nearly one out of 10 HCV+ coexisted with HBV (8.9%), and the risk became synergistic, with 2/3 of them dying from liver-related causes. Kidney cancer (5.46), diabetes (2.31), and stroke (1.91) were also significantly increased. In the order of ranking All Cause mortality risks among HCV+ subjects, diabetes (4.5), proteinuria (4.1), smoking (3.5), obesity (3.3), drinking (3.2) and hypertension (2.9) were all significantly increased. Conclusion: The life expectancy of HCV+ carriers was shortened by 7.37–8.45 years. While the main effect was liver cancer and cirrhosis, HCV also involved kidney damage, producing proteinuria and reduced GFR, and led to an increased mortality from diabetes and stroke. The ranking order of reducible HCV risks were diabetes, CKD including proteinuria, smoking, obesity, drinking and hypertension. Citation Information: Cancer Prev Res 2010;3(1 Suppl):B135.