10 results on '"Moayyeri, Alireza"'
Search Results
2. Evidence Based Medicine: Does It Make A Difference?
- Author
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Druss, Benjamin, Glasziou, Paul, Kernick, David P., Gerhardus, Ansgar, Wilson, Tim, Ben-Shlomo, Yoav, Moayyeri, Alireza, Soltani, Akbar, and Twisselmann, Birte
- Published
- 2005
3. Improving visualisation and interpretation of metabolome-wide association studies (MWAS):an application in a population based cohort using untargeted 1H NMR metabolic profiling
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Castagné, Raphaële, Boulangé, Claire Laurence, Karaman, Ibrahim, Campanella, Gianluca, Dos Santos Ferreira, Diana, Kaluarachchi, Manuja R., Lehne, Benjamin, Moayyeri, Alireza, Lewis, Matthew R., Spagou, Konstantina, Dona, Anthony C., Evangelos, Vangelis, Tracy, Russell, Greenland, Philip, Lindon, John C., Herrington, David, Ebbels, Timothy M. D., Elliott, Paul, Tzoulaki, Joanna, and Chadeau-Hyam, Marc
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metabolome-wide association studies ,MWAS ,Epidemiology ,metabolomics ,untargeted ,NUCLEAR MAGNETIC-RESONANCE - Abstract
1H nuclear magnetic resonance (NMR) spectroscopy of biofluids generates reproducible data allowing detection and quantification of small molecules in large population cohorts.Statistical models to analyse such data are now well-established, and the use of univariate metabolome wide association studies (MWAS) investigating the spectral features separately has emerged as a computationally efficient and interpretable alternative to multivariate models. The MWAS relies on the accurate estimation of a metabolome wide significance level (MWSL) to be applied to control the family-wise error rate. Subsequent interpretation requires efficient visualization and formal feature annotation, which, in-turn, calls for efficient prioritisation of spectral variables of interest.Using human serum 1H NMR spectroscopic profiles from 3,948 participants from the Multi-Ethnic Study of Atherosclerosis (MESA), we have performed a series of MWAS for serum levels of glucose. We first propose an extension of the conventional MWSL that yields stable estimates of the MWSL across the different model parametrisations and distributional features of the outcome. We propose both efficient visualisation methods, and a strategy based on subsampling and internal validation to prioritize the associations. Our work proposes and illustrates practical and scalable solutions to facilitate the implementation of the MWAS approach and improve interpretation in large cohort studies.
- Published
- 2017
4. A workflow for integrated processing of multi-cohort untargeted 1H NMR metabolomics data in large scale metabolic epidemiology
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Karaman, Ibrahim, Ferreira, Diana L. S., Boulangé, Claire L., Kaluarachchi, Manuja R., Herrington, David, Dona, Anthony C., Castagné, Raphaële, Moayyeri, Alireza, Lehne, Benjamin, Loh, Marie, de Vries, Paul S., Dehghan, Abbas, Franco, Oscar H., Hofman, Albert, Evangelou, Evangelos, Tzoulaki, Ioanna, Elliott, Paul, Lindon, John C., Ebbels, Timothy M. D., National Institute for Health Research, Commission of the European Communities, Medical Research Council (MRC), European Molecular Biology Laboratory, and Epidemiology
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0301 basic medicine ,Normalization (statistics) ,Biochemistry & Molecular Biology ,Computer science ,computer.software_genre ,01 natural sciences ,Biochemistry ,03 medical and health sciences ,Metabolomics ,Preprocessor ,Integrated processing ,quality control ,preprocessing ,010401 analytical chemistry ,alignment ,General Chemistry ,06 Biological Sciences ,metabolomics ,NMR ,0104 chemical sciences ,030104 developmental biology ,Workflow ,normalization ,Outlier ,Proton NMR ,large scale ,epidemiology ,Data mining ,multicohort ,03 Chemical Sciences ,computer ,Two-dimensional nuclear magnetic resonance spectroscopy - Abstract
Large-scale metabolomics studies involving thousands of samples present multiple challenges in data analysis, particularly when an untargeted platform is used. Studies with multiple cohorts and analysis platforms exacerbate existing problems such as peak alignment and normalization. Therefore, there is aneed for robust processing pipelines which can ensure reliable data for statistical analysis. The COMBIBIO project incorporates serum from approximately 8000 individuals, in 3 cohorts, profiled by 6 assays in 2 phases using both 1H-NMR and UPLC-MS. Here we present the COMBI-BIO NMR analysis pipeline and demonstrate its fitness for purpose using representative quality control (QC) samples. NMR spectra were first aligned and normalized. After eliminating interfering signals, outliers identified using Hotelling’s T2 were removed and a cohort/phase adjustment was applied, resulting in two NMR datasets (CPMG and NOESY). Alignment of the NMR data was shown to increase the correlation-based alignment quality measure from 0.319 to 0.391 for CPMG and from 0.536 to 0.586 for NOESY, showing that the improvement was present across both large and small peaks. End-to-end quality assessment of the pipeline was achieved using Hotelling’s T2 distributions. For CPMG spectra, the interquartile range decreased from 1.425 in raw QC data to 0.679 in processed spectra, while the corresponding change for NOESY spectra was from 0.795 to 0.636 indicating an improvement in precision following processing. PCA indicated that gross phase and cohort differences were no longer present. These results illustrate that the pipeline produces robust and reproducible data, successfully addressing the methodological challenges of this large multi-faceted study.
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- 2016
5. Cohort Profile: TwinsUK and Healthy Ageing Twin Study.
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Moayyeri, Alireza, Hammond, Christopher J, Valdes, Ana M, and Spector, Timothy D
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TWINS , *GENETIC transcription , *EPIGENETICS , *EPIDEMIOLOGY , *FOLLOW-up studies (Medicine) , *COHORT analysis - Abstract
The UK's largest registry of adult twins, or TwinsUK Registry, started in 1992 and encompasses about 12 000 volunteer twins from all over the United Kingdom. More than 70% of the registered twins have filled at least one detailed health questionnaire and about half of them undergone a baseline comprehensive assessment and two follow-up clinical evaluations. The most recent follow-up visit, known as Healthy Ageing Twin Study (HATS), involved 3125 female twins aged >40 years with at least one previous clinical assessment to enable inspection of longitudinal changes in ageing traits and their genetic and environmental components. The study benefits from several state-of-the-art OMICs studies including genome-wide association, next-generation genome and transcriptome sequencing, and epigenetic and metabolomic profiles. This makes our cohort as one of the most deeply phenotyped and genotyped in the world. Several collaborative projects in the field of epidemiology of complex disorders are ongoing in our cohort and interested researchers are encouraged to get in contact for future collaborations. [ABSTRACT FROM PUBLISHER]
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- 2013
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6. The association between physical activity in different domains of life and risk of osteoporotic fractures
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Moayyeri, Alireza, Besson, Hervé, Luben, Robert N., Wareham, Nicholas J., and Khaw, Kay-Tee
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PHYSICAL activity , *OSTEOPOROSIS , *RISK factors of fractures , *EPIDEMIOLOGY , *QUESTIONNAIRES , *ULTRASONIC imaging - Abstract
Abstract: A large body of epidemiological evidence suggests an inverse relationship between physical activity and risk of fractures. However, it is unclear how this association varies according to the domain of life in which the activity is undertaken. In this analysis of the European Prospective Investigation of Cancer-Norfolk study, we assessed total and domain-specific physical activity using a validated questionnaire (EPAQ2) in 14,903 participants (6514 men, mean age 62year) who also underwent quantitative ultrasound of the heel. After a median follow-up of 7.5years, there were 504 fractures of which 164 were hip fractures. In multivariable linear regression analysis, broadband ultrasound attenuation (BUA) was positively associated with total and leisure-time activities while showing no association with transportation and work activities. Home activities were associated with a lower BUA among younger participants. In multivariable Cox proportional-hazards models, moderate activities at home and in leisure time were associated with lower hip fracture risk among women (hazard ratios [HR] 0.51 and 0.55, p value 0.02 and 0.03, respectively). Among men, leisure-time activities were associated with lower risk of hip fracture (HR=0.58; p for trend<0.001) whereas activities at home were associated with higher risk of any fracture (HR=1.25; p for trend=0.008). Walking for leisure or transport was associated with lower risk of fracture in both men and women. Multivariable fractional polynomial modelling showed a U-shaped association between home activities and fracture risk especially among women. This study suggests that different domains of physical activity may relate differently to fracture risk and these relationships may vary by sex. [ABSTRACT FROM AUTHOR]
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- 2010
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7. The effect of including quantitative heel ultrasound in models for estimation of 10-year absolute risk of fracture
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Moayyeri, Alireza, Kaptoge, Stephen, Dalzell, Nichola, Luben, Robert N., Wareham, Nicholas J., Bingham, Sheila, Reeve, Jonathan, and Khaw, Kay Tee
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OSTEORADIOGRAPHY , *MEDICAL ultrasonics , *HEEL bone fractures , *ESTIMATION theory , *PROPORTIONAL hazards models , *RISK assessment , *PHYSICIAN practice patterns , *BONE densitometry - Abstract
Abstract: The role of quantitative ultrasound (QUS) in clinical practice is debatable. An unanswered question is that whether combining QUS and BMD measurements could improve the prediction of fracture risk. We examined this in a sample of men and women in the European Prospective Investigation into Cancer (EPIC)-Norfolk who had both heel QUS and hip DXA between 1995 and 1997 and were followed for any incident fracture up to 2007. From 1455 participants (703 men) aged 65–76 years at baseline, 79 developed a fracture over 10.3±1.4 years of follow-up. Two separate sex-stratified Cox proportional-hazard models were used including clinical risk factors and total hip BMD. Heel broadband ultrasound attenuation (BUA) was also included in the second model. Global measures of model fit, area under ROC curve, and the Hosmer–Lemeshow statistic showed relative superiority of the model including BUA. Using each model, we calculated 10-year absolute risk of fracture for all participants and categorized them in groups of <5%, 5% to <15%, and ≥15%. Comparison of groupings showed a total re-classification of 16.6% of participants after inclusion of BUA with the greatest re-classification (30.7%) among the group with intermediate risk. Adding a QUS measurement to models based on clinical risk factors and BMD improves the predictive power of models and suggests that further attention should be paid to QUS as a clinical tool for fracture risk assessment. [Copyright &y& Elsevier]
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- 2009
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8. The importance and applications of absolute fracture risk estimation in clinical practice and research
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Moayyeri, Alireza
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- 2009
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9. Is QUS or DXA Better for Predicting the 10-Year Absolute Risk of Fracture?
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Moayyeri, Alireza, Kaptoge, Stephen, Dalzell, Nichola, Bingham, Sheila, Luben, Robert N., Wareham, Nicholas J., Reeve, Jonathan, and Khaw, Kay Tee
- Abstract
The article discusses a study on the predictive capability of quantitative ultrasound (QUS) and dual x-ray absorptiometry (DXA) in terms of the 10-year absolute risk of fracture. It notes that DXA stands as the accepted reference method in bone mass density (BMD) measurement while a decline in BMD is linked to an increased risk of fracture. Under the study, the participants were subjected to either hip BMD measurement and QUS assessment. Results show that QUS assessment exhibited performance that is similar to that of DXA in predicting fracture risks.
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- 2009
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10. Incidence and characteristics of falls leading to hip fracture in Iranian population
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Abolhassani, Farid, Moayyeri, Alireza, Naghavi, Mohsen, Soltani, Akbar, Larijani, Bagher, and Shalmani, Hamidreza Tavakoli
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BONE fractures in old age , *ACCIDENTAL falls in old age , *HIP joint injuries , *ACCIDENTS , *MULTIVARIATE analysis - Abstract
Abstract: An estimated one in three adults aged 65 years or older falls each year, making falls a major health concern. Hip fractures are the most serious consequences of falls in elderly people. Identifying the characteristics of falls leading to hip fracture may provide information about high risk individuals, environment, and activities useful for the development of intervention strategies. Little is known, however, about the incidence and characteristics of falls leading to hip fracture in Middle Eastern countries. Therefore, the authors presented data from the Iranian Multicenter Study on Accidental Injuries, a prospective population-based study conducted in 9 provinces of Iran in 2003. All the hospitals serving about 9.5 million people in the study area were prospectively surveyed for any incident injury resulting from accidental events. A total of 2186 patients (1372 male, 814 female) were admitted due to any injurious fall events, where 572 (26.2%) of them suffered a hip fracture. Annual incidence rates of injurious fall events and related hip fractures were 116.3 and 30.4 per 100,000 person-years, respectively. These figures were 237.1 and 93.6 per 100,000 person-years for people over the age of 50 years, respectively. 71% of fall injuries and 76% of hip fractures occurred indoors. Among 450 patients with hip fractures ≥50 years of age, 61.8% arose from a fall from standing height or less. Only 1 in these 450 hip fractures occurred at the time of recreational activity. In multivariate logistic regression analysis, no factor was an independent predictor of hip fractures comparing to other fall-related injuries among younger participants (≥20 and <50 years). For older patients, falls from standing height or loss (odds ratio (OR) = 2.67), falls during walking (OR = 1.71), and falls on stairs (OR = 1.73) were detected as risk factors of hip fracture. Married persons and those falling from a ladder or other elevations were less likely to fracture their hip in this age group. Our data suggest that modification of the factors external to the homes is less likely to prevent more than a small proportion of fall-related hip fractures in Iran. Further studies on this topic have potential applications for developing preventive strategies. [Copyright &y& Elsevier]
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- 2006
- Full Text
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