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11 Publications visible to you, out of a total of 11
Incremental value of Veterans Specific Activity Questionnaire and the YMCA-step test for the assessment of cardiorespiratory fitness in population-based studies.
LIFE Heart

Abstract (Expand)

BACKGROUND: Cardiorespiratory fitness is a well-established independent predictor of cardiovascular health. However, the relevance of alternative exercise and non-exercise tests for cardiorespiratory … fitness assessment in large cohorts has not been studied in detail. We aimed to evaluate the YMCA-step test and the Veterans Specific Activity Questionnaire (VSAQ) for the estimation of cardiorespiratory fitness in the general population. METHODS: One hundred and five subjects answered the VSAQ, performed the YMCA-step test and a maximal cardiopulmonary exercise test (CPX) and gave BORG ratings for both exercise tests (BORGSTEP, BORGCPX). Correlations of peak oxygen uptake on a treadmill (VO2_PEAK) with VSAQ, BORGSTEP, one-minute, post-exercise heartbeat count, and peak oxygen uptake during the step test (VO2_STEP) were determined. Moreover, the incremental values of the questionnaire and the step test in addition to other fitness-related parameters were evaluated using block-wise hierarchical regression analysis. RESULTS: Eighty-six subjects completed the step test according to the protocol. For completers, correlations of VO2_PEAK with the age- and gender-adjusted VSAQ, heartbeat count and VO2_STEP were 0.67, 0.63 and 0.49, respectively. However, using hierarchical regression analysis, age, gender and body mass index already explained 68.8% of the variance of VO2_PEAK, while the additional benefit of VSAQ was rather low (3.4%). The inclusion of BORGSTEP, heartbeat count and VO2_STEP increased R(2) by a further 2.2%, 3.3% and 5.6%, respectively, yielding a total R(2) of 83.3%. CONCLUSIONS: Neither VSAQ nor the YMCA-step test contributes sufficiently to the assessment of cardiorespiratory fitness in population-based studies.

Authors: A. Teren, S. Zachariae, F. Beutner, R. Ubrich, M. Sandri, C. Engel, M. Loffler, S. Gielen

Date Published: 15th Dec 2015

Publication Type: Not specified

The value of noncoronary atherosclerosis for identifying coronary artery disease: results of the Leipzig LIFE Heart Study.
Genetical Statistics and Systems Biology, LIFE Heart

Abstract (Expand)

BACKGROUND: Despite the widespread use of noninvasive testing prior to invasive coronary diagnostic the diagnostic yield of elective coronary angiography has been reported low in subjects with suspected … obstructive CAD. OBJECTIVE: To determine the predictive value of noncoronary atherosclerosis (NCA) in subjects with suspected stable coronary artery disease (CAD) intended to invasive coronary angiography. METHODS: Ultrasound-based assessment of carotid artery plaque (CAP), carotid intima-media thickness (CIMT) and ankle-brachial index (ABI) was performed in 2216 subjects with suspected CAD prior to coronary angiography. Logistic regression and c-statistics were used to analyze the diagnostic value of NCA for the presence of obstructive CAD and the intention to revascularization. RESULTS: Percentage of positive results of elective coronary angiography was low but comparable to other studies (41% obstructive CAD). We identified 1323 subjects (60%) with NCA, most of them were characterized by CAP (93%). CAP independently predicted obstructive CAD in addition to traditional risk factors and clinical factors while CIMT and ABI failed to improve the prediction. The presence of NCA and typical angina were the strongest predictors for obstructive CAD (OR 4.0 and 2.4, respectively). A large subgroup of patients (n = 703, 32%) with atypical clinical presentation and lack of NCA revealed a low indication for revascularization <15% indicating a large proportion of subjects with non-obstructive CAD in this subgroup. CONCLUSION: The evaluation of noncoronary atherosclerosis has the potential to impact clinical decision making and to direct subsequent diagnostic procedures in subjects with suspected coronary artery disease. CLINICAL TRIAL REGISTRATION: NCT00497887.

Authors: A. Weissgerber, M. Scholz, A. Teren, M. Sandri, D. Teupser, S. Gielen, J. Thiery, G. Schuler, F. Beutner

Date Published: 13th Sep 2015

Publication Type: Not specified

Human Diseases: coronary artery disease, atherosclerosis

Dissecting the genetics of the human transcriptome identifies novel trait-related trans-eQTLs and corroborates the regulatory relevance of non-protein coding locidagger.
Genetical Statistics and Systems Biology, LIFE Heart

Abstract (Expand)

Genetics of gene expression (eQTLs or expression QTLs) has proved an indispensable tool for understanding biological pathways and pathomechanisms of trait-associated SNPs. However, power of most … genome-wide eQTL studies is still limited. We performed a large eQTL study in peripheral blood mononuclear cells of 2112 individuals increasing the power to detect trans-effects genome-wide. Going beyond univariate SNP-transcript associations, we analyse relations of eQTLs to biological pathways, polygenetic effects of expression regulation, trans-clusters and enrichment of co-localized functional elements. We found eQTLs for about 85% of analysed genes, and 18% of genes were trans-regulated. Local eSNPs were enriched up to a distance of 5 Mb to the transcript challenging typically implemented ranges of cis-regulations. Pathway enrichment within regulated genes of GWAS-related eSNPs supported functional relevance of identified eQTLs. We demonstrate that nearest genes of GWAS-SNPs might frequently be misleading functional candidates. We identified novel trans-clusters of potential functional relevance for GWAS-SNPs of several phenotypes including obesity-related traits, HDL-cholesterol levels and haematological phenotypes. We used chromatin immunoprecipitation data for demonstrating biological effects. Yet, we show for strongly heritable transcripts that still little trans-chromosomal heritability is explained by all identified trans-eSNPs; however, our data suggest that most cis-heritability of these transcripts seems explained. Dissection of co-localized functional elements indicated a prominent role of SNPs in loci of pseudogenes and non-coding RNAs for the regulation of coding genes. In summary, our study substantially increases the catalogue of human eQTLs and improves our understanding of the complex genetic regulation of gene expression, pathways and disease-related processes.

Authors: H. Kirsten, H. Al-Hasani, L. Holdt, A. Gross, F. Beutner, K. Krohn, K. Horn, P. Ahnert, R. Burkhardt, K. Reiche, J. Hackermuller, M. Loffler, D. Teupser, J. Thiery, M. Scholz

Date Published: 15th Aug 2015

Publication Type: Journal article

Validation of a brief step-test protocol for estimation of peak oxygen uptake.
LIFE Heart

Abstract (Expand)

BACKGROUND: Physical exercise capacity has been shown to predict cardiovascular disease incidence and is increasingly measured in epidemiological studies. However, direct measurement of peak oxygen … uptake is too time consuming in large-scale studies. We therefore investigated whether a brief 3-minute step-test protocol can be used to estimate peak oxygen uptake in these settings. DESIGN AND METHODS: A group of 97 subjects performed the YMCA step test and a maximal treadmill test with continuous measurement of oxygen uptake. Correlation and linear regression analyses were used to identify VO2peak predictors obtained from the step test and to develop models for VO2peak estimation. RESULTS: The YMCA model, including the 1-minute heart beat count, predicted VO2peak with R = 0.83. A novel simplified model based on the heart rate at 45 s of recovery performed comparable (R = 0.83). However, models based on heart rate measures were only valid in subjects who completed the test according to protocol, but not in subjects who terminated prematurely. For the applicability in subjects with low exercise capacity, a new model including gas exchange analysis enabled prediction of VO2peak (R = 0.89). All models were validated in an independent sample (r = 0.86-0.91). Exercise time of the step test was less than one-hird of standard ergospirometry (treadmill test: 654 +/- 151 s, step test: 180 s, p < 0.001). CONCLUSION: In large-scale epidemiological studies with limited time slots for exercise testing and significant proportions of subjects with low exercise capacity a modified version of the YMCA step test may be used to predict VO2peak.

Authors: F. Beutner, R. Ubrich, S. Zachariae, C. Engel, M. Sandri, A. Teren, S. Gielen

Date Published: 1st May 2014

Publication Type: Not specified

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