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Chen X, Chen L. Causal Links Between Systemic Disorders and Keratoconus in European Population. Am J Ophthalmol 2024; 265:189-199. [PMID: 38705552 DOI: 10.1016/j.ajo.2024.04.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 04/28/2024] [Accepted: 04/30/2024] [Indexed: 05/07/2024]
Abstract
PURPOSE To establish the presence of a causal linkage between prevalent systemic diseases and keratoconus (KC). DESIGN Mendelian randomization (MR) analysis. METHODS After an exhaustive screening process, genetic variants linked to various systemic diseases were identified as instrumental variables at the genome-wide significance level. Subsequently, MR analyses were conducted to elucidate their potential causal connection with KC (N = 26,742). The encompassed systemic ailments comprise diabetes, hay fever/allergic rhinitis/eczema, obstructive sleep apnea, thyroid dysfunction, aortic aneurysm, major depressive disorder, inflammatory bowel disease (including Crohn's disease and ulcerative colitis), and mitral valve prolapse. Our study adheres to the principles of Strengthening the Reporting of Observational Studies in Epidemiology Using MR guidelines. RESULTS Using inverse variance weighting as the primary MR analysis method, our findings revealed that hay fever/allergic rhinitis/eczema (odds ratio, 10.144; 95% CI, 2.441-42.149; P = .001) and ulcerative colitis (odds ratio, 1.147; 95% CI, 1.054-1.248; P = .002) were associated with an increased risk of KC within the largest population under scrutiny. Conversely, the prolonged hyperglycemic state did not exhibit a potentially protective effect in delaying the pathogenesis of KC, and no correlation was observed between the two (odds ratio, 0.320; 95% CI, 0.029-3.549; P = .353). Also, obstructive sleep apnea, thyroid function, aortic aneurysm, major depressive disorder, Crohn's disease, and mitral valve prolapse did not exhibit a causal association with KC (P > .05 for all comparisons). CONCLUSIONS This study indicates an increased risk of KC related to hay fever/allergic rhinitis/eczema and ulcerative colitis, with diabetes not providing a protective effect. These findings may potentially contribute some insights to inform clinical interventions.
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Affiliation(s)
- Xiaxue Chen
- From the Department of Ophthalmology (X.C.), The Second Hospital of Jilin University, Changchun, Jilin, China.
| | - Lanlan Chen
- Department of Hepatobiliary and Pancreatic Surgery (L.C.), General Surgery Center, The First Hospital of Jilin University, Changchun, Jilin, China
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Zhuang X, Chen P, Yang R, Man X, Wang R, Shi Y. Mendelian randomization analysis reveals the combined effects of epigenetics and telomere biology in hematologic cancers. Clin Epigenetics 2024; 16:120. [PMID: 39192284 DOI: 10.1186/s13148-024-01728-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2024] [Accepted: 08/12/2024] [Indexed: 08/29/2024] Open
Abstract
BACKGROUND Telomere shortening and epigenetic modifications are key factors in aging and hematologic diseases. This study investigates the relationship of telomere length and epigenetic age acceleration (EAA) with hematologic cancers, blood cells, and biochemical markers through the epigenetic clocks. METHODS This study primarily utilizes genome-wide association studies of populations of European descent as instrumental variables, exploring the causal relationships between exposures and outcomes through a bidirectional two-sample Mendelian randomization (MR) approach. MR techniques include inverse variance weighted (IVW), MR Egger, and weighted median modes. Heterogeneity and pleiotropy in MR are assessed using Cochran's Q test and the MR Egger intercept, with the robustness of the conclusions further validated by multivariable MR (MVMR). RESULTS Our research shows that longer telomere lengths significantly increase the risk of multiple myeloma, leukemia, and lymphoma (OR > 1, P < 0.05) and establish a causal relationship between telomere length and red blood cell indices such as RBC (OR = 1.121, PIVW = 0.034), MCH (OR = 0.801, PIVW = 2.046e-06), MCV (OR = 0.801, PIVW = 0.001), and MCHC (OR = 0.813, PIVW = 0.002). Additionally, MVMR analysis revealed an association between DNA methylation PhenoAge acceleration and alkaline phosphatase (OR = 1.026, PIVW = 0.007). CONCLUSION The study clarifies the relationships between telomere length, EAA, and hematological malignancies, further emphasizing the prognostic significance of telomere length and EAA. This deepens our understanding of the pathogenesis of hematological diseases, which can inform risk assessment and therapeutic strategies.
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Affiliation(s)
- Xin Zhuang
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Peng Chen
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Rong Yang
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xiaoying Man
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Ruochen Wang
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Yifen Shi
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
- Qinghai Province Women and Children's Hospital, Wenzhou, China.
- Zhejiang Provincial Clinical Research Center for Hematological Disorders, Wenzhou, China.
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Zhu M, Ling S. Potential causal association of diabetes mellitus and blood glucose related indexes with the onset of epilepsy: a two-sample Mendelian randomization study. Front Neurol 2024; 15:1399504. [PMID: 38962478 PMCID: PMC11221190 DOI: 10.3389/fneur.2024.1399504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 05/14/2024] [Indexed: 07/05/2024] Open
Abstract
Aim Diabetes mellitus (DM) may promote the occurrence of epilepsy through mechanisms, such as inflammation, immune imbalance, and cerebrovascular injury, caused by metabolic abnormalities. However, evidence for the effects of DM and blood glucose (BG) on the risk of epilepsy is limited. Herein, this study used the Mendelian randomization (MR) method to investigate the potential causal associations of DM and BG-related indexes with epilepsy. Methods In this two-sample MR study, summary statistics data of the genome-wide association studies (GWASs) on exposures, including type 1 diabetes mellitus (T1DM), T2DM, fasting glucose, and glycated hemoglobin (HbAlc), were extracted from the MRC-Integrative Epidemiology Unit (MRC-IEU). The GWAS data on study outcomes, including epilepsy, focal epilepsy, and generalized epilepsy, were obtained from the FinnGen consortium. MR-Egger regression was used to examine horizontal pleiotropism of instrumental variables (IVs), and Cochran's Q statistics was used to quantify the heterogeneity. MR analysis methods including inverse variance weighted (IVW) tests, weighted median, and MR-Egger were utilized to investigate the causal associations between DM and BG-related indexes with epilepsy. The evaluation indexes were odds ratios (ORs) and 95% confidence intervals (CIs). Reverse causal association analyses were also performed. In addition, IVW-radial and leave-one-out tests were utilized for sensitivity analyses. Results IVW estimates suggested that T1DM has potential causal associations with epilepsy (OR = 1.057, 95% CI: 1.031-1.084) and generalized epilepsy (OR = 1.066, 95% CI: 1.018-1.116). No significant reverse causal associations of T1DM with epilepsy or generalized epilepsy were found (all P > 0.05). In addition, sensitivity analysis results identified no outlier, indicating that the associations of T1DM with epilepsy and generalized epilepsy were relatively robust. Conclusion Patients with T1DM had a potential risk of developing epilepsy, and prompt treatment of DM and dynamic monitoring may be beneficial to prevent epilepsy in this high-risk population. However, the causal associations of DM and BG with epilepsy may warrant further verification.
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Affiliation(s)
- Mengting Zhu
- Department of Neurology, The Fifth People's Hospital of Wujiang District, Suzhou, Jiangsu, China
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Ke TM, Lophatananon A, Muir KR. Strengthening the Evidence for a Causal Link between Type 2 Diabetes Mellitus and Pancreatic Cancer: Insights from Two-Sample and Multivariable Mendelian Randomization. Int J Mol Sci 2024; 25:4615. [PMID: 38731833 PMCID: PMC11082974 DOI: 10.3390/ijms25094615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 05/13/2024] Open
Abstract
This two-sample Mendelian randomization (MR) study was conducted to investigate the causal associations between type 2 diabetes mellitus (T2DM) and the risk of pancreatic cancer (PaCa), as this causal relationship remains inconclusive in existing MR studies. The selection of instrumental variables for T2DM was based on two genome-wide association study (GWAS) meta-analyses from European cohorts. Summary-level data for PaCa were extracted from the FinnGen and UK Biobank databases. Inverse variance weighted (IVW) and four other robust methods were employed in our MR analysis. Various sensitivity analyses and multivariable MR approaches were also performed to enhance the robustness of our findings. In the IVW and Mendelian Randomization Pleiotropy RESidual Sum and Outlier (MR-PRESSO) analyses, the odds ratios (ORs) for each 1-unit increase in genetically predicted log odds of T2DM were approximately 1.13 for PaCa. The sensitivity tests and multivariable MR supported the causal link between T2DM and PaCa without pleiotropic effects. Therefore, our analyses suggest a causal relationship between T2DM and PaCa, shedding light on the potential pathophysiological mechanisms of T2DM's impact on PaCa. This finding underscores the importance of T2DM prevention as a strategy to reduce the risk of PaCa.
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Affiliation(s)
| | | | - Kenneth R. Muir
- Division of Population Health, Health Services Research and Primary Care, School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK; (T.-M.K.); (A.L.)
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Casanova F, Tian Q, Atkins JL, Wood AR, Williamson D, Qian Y, Zweibaum D, Ding J, Melzer D, Ferrucci L, Pilling LC. Iron and risk of dementia: Mendelian randomisation analysis in UK Biobank. J Med Genet 2024; 61:435-442. [PMID: 38191510 DOI: 10.1136/jmg-2023-109295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 11/28/2023] [Indexed: 01/10/2024]
Abstract
BACKGROUND Brain iron deposition is common in dementia, but whether serum iron is a causal risk factor is unknown. We aimed to determine whether genetic predisposition to higher serum iron status biomarkers increased risk of dementia and atrophy of grey matter. METHODS We analysed UK Biobank participants clustered into European (N=451284), African (N=7477) and South Asian (N=9570) groups by genetic similarity to the 1000 genomes project. Using Mendelian randomisation methods, we estimated the association between genetically predicted serum iron (transferrin saturation [TSAT] and ferritin), grey matter volume and genetic liability to clinically defined dementia (including Alzheimer's disease [AD], non-AD dementia, and vascular dementia) from hospital and primary care records. We also performed time-to-event (competing risks) analysis of the TSAT polygenic score on risk of clinically defined non-AD dementia. RESULTS In Europeans, higher genetically predicted TSAT increased genetic liability to dementia (Odds Ratio [OR]: 1.15, 95% Confidence Intervals [CI] 1.04 to 1.26, p=0.0051), non-AD dementia (OR: 1.27, 95% CI 1.12 to 1.45, p=0.00018) and vascular dementia (OR: 1.37, 95% CI 1.12 to 1.69, p=0.0023), but not AD (OR: 1.00, 95% CI 0.86 to 1.15, p=0.97). Higher TSAT was also associated with increased risk of non-AD dementia in participants of African, but not South Asian groups. In survival analysis using a TSAT polygenic score, the effect was independent of apolipoprotein-E ε4 genotype (with adjustment subdistribution Hazard Ratio: 1.74, 95% CI 1.33 to 2.28, p=0.00006). Genetically predicted TSAT was associated with lower grey matter volume in caudate, putamen and thalamus, and not in other areas of interest. DISCUSSION Genetic evidence supports a causal relationship between higher TSAT and risk of clinically defined non-AD and vascular dementia, in European and African groups. This association appears to be independent of apolipoprotein-E ε4.
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Affiliation(s)
- Francesco Casanova
- Department of Clinical and Biomedical Sciences, University of Exeter, Exeter, UK
| | - Qu Tian
- Translational Gerontology Branch Longitudinal Studies Section, National Institute on Aging, Bethesda, Maryland, USA
| | - Janice L Atkins
- Department of Clinical and Biomedical Sciences, University of Exeter, Exeter, UK
| | - Andrew R Wood
- Department of Clinical and Biomedical Sciences, University of Exeter, Exeter, UK
| | | | - Yong Qian
- Translational Gerontology Branch Longitudinal Studies Section, National Institute on Aging, Bethesda, Maryland, USA
| | - David Zweibaum
- Translational Gerontology Branch Longitudinal Studies Section, National Institute on Aging, Bethesda, Maryland, USA
| | - Jun Ding
- Translational Gerontology Branch Longitudinal Studies Section, National Institute on Aging, Bethesda, Maryland, USA
| | - David Melzer
- Department of Clinical and Biomedical Sciences, University of Exeter, Exeter, UK
| | - Luigi Ferrucci
- Translational Gerontology Branch Longitudinal Studies Section, National Institute on Aging, Bethesda, Maryland, USA
| | - Luke C Pilling
- Department of Clinical and Biomedical Sciences, University of Exeter, Exeter, UK
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Yamazaki H, Streicher SA, Wu L, Fukuhara S, Wagner R, Heni M, Grossman SR, Lenz HJ, Setiawan VW, Le Marchand L, Huang BZ. Evidence for a causal link between intra-pancreatic fat deposition and pancreatic cancer: A prospective cohort and Mendelian randomization study. Cell Rep Med 2024; 5:101391. [PMID: 38280379 PMCID: PMC10897551 DOI: 10.1016/j.xcrm.2023.101391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 11/24/2023] [Accepted: 12/29/2023] [Indexed: 01/29/2024]
Abstract
Prior observational studies suggest an association between intra-pancreatic fat deposition (IPFD) and pancreatic ductal adenocarcinoma (PDAC); however, the causal relationship is unclear. To elucidate causality, we conduct a prospective observational study using magnetic resonance imaging (MRI)-measured IPFD data and also perform a Mendelian randomization study using genetic instruments for IPFD. In the observational study, we use UK Biobank data (N = 29,463, median follow-up: 4.5 years) and find that high IPFD (>10%) is associated with PDAC risk (adjusted hazard ratio [HR]: 3.35, 95% confidence interval [95% CI]: 1.60-7.00). In the Mendelian randomization study, we leverage eight out of nine IPFD-associated genetic variants (p < 5 × 10-8) from a genome-wide association study in the UK Biobank (N = 25,617) and find that genetically determined IPFD is associated with PDAC (odds ratio [OR] per 1-standard deviation [SD] increase in IPFD: 2.46, 95% CI: 1.38-4.40) in the Pancreatic Cancer Cohort Consortium I, II, III (PanScan I-III)/Pancreatic Cancer Case-Control Consortium (PanC4) dataset (8,275 PDAC cases and 6,723 non-cases). This study provides evidence for a potential causal role of IPFD in the pathogenesis of PDAC. Thus, reducing IPFD may lower PDAC risk.
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Affiliation(s)
- Hajime Yamazaki
- Section of Clinical Epidemiology, Department of Community Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Center for Innovative Research for Communities and Clinical Excellence (CiRC2LE), Fukushima Medical University, Fukushima, Japan.
| | - Samantha A Streicher
- Cancer Epidemiology Division, Population Sciences in the Pacific Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Lang Wu
- Cancer Epidemiology Division, Population Sciences in the Pacific Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Shunichi Fukuhara
- Section of Clinical Epidemiology, Department of Community Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Center for Innovative Research for Communities and Clinical Excellence (CiRC2LE), Fukushima Medical University, Fukushima, Japan; Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Róbert Wagner
- Department of Endocrinology and Diabetology, University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany; Institute for Clinical Diabetology, German Diabetes Center (DDZ), Leibniz Center for Diabetes Research at Heinrich-Heine University, Düsseldorf, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Martin Heni
- Division of Endocrinology and Diabetology, Department of Internal Medicine I, Ulm University, Ulm, Germany; Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tübingen, Tübingen, Germany
| | - Steven R Grossman
- Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, USA; Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Heinz-Josef Lenz
- Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, USA; Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Veronica Wendy Setiawan
- Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, USA; Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; Department of Population and Public Health Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Loïc Le Marchand
- Cancer Epidemiology Division, Population Sciences in the Pacific Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Brian Z Huang
- Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, USA; Department of Population and Public Health Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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Garfield V, Anderson EL. A brief comparison of polygenic risk scores and Mendelian randomisation. BMC Med Genomics 2024; 17:10. [PMID: 38166888 PMCID: PMC10763343 DOI: 10.1186/s12920-023-01769-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 12/07/2023] [Indexed: 01/05/2024] Open
Abstract
Mendelian randomisation and polygenic risk score analysis have become increasingly popular in the last decade due to the advent of large-scale genome-wide association studies. Each approach has valuable applications, some of which are overlapping, yet there are important differences which we describe here.
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Affiliation(s)
- Victoria Garfield
- MRC Unit for Lifelong Health and Ageing, Institute of Cardiovascular Science, UCL, 1-19 Torrington Place, London, WC1E 7HB, UK.
| | - Emma L Anderson
- Division of Psychiatry, University College London, 149 Maple House, Tottenham Court Road, London, W1T 7NF, UK
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Ahmed A, Amin H, Drenos F, Sattar N, Yaghootkar H. Genetic Evidence Strongly Supports Managing Weight and Blood Pressure in Addition to Glycemic Control in Preventing Vascular Complications in People With Type 2 Diabetes. Diabetes Care 2023; 46:1783-1791. [PMID: 37556814 DOI: 10.2337/dc23-0855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Accepted: 07/05/2023] [Indexed: 08/11/2023]
Abstract
OBJECTIVE To investigate the causal association of type 2 diabetes and its components with risk of vascular complications independent of shared risk factors obesity and hypertension and to identify the main driver of this risk. RESEARCH DESIGN AND METHODS We conducted Mendelian randomization (MR) using independent genetic variants previously associated with type 2 diabetes, fasting glucose, HbA1c, fasting insulin, BMI, and systolic blood pressure as instrumental variables. We obtained summary-level data for 18 vascular diseases (15 for type 2 diabetes) from FinnGen and publicly available genome-wide association studies as our outcomes. We conducted univariable and multivariable MR, in addition to sensitivity tests to detect and minimize pleiotropic effects. RESULTS Univariable MR analysis showed that type 2 diabetes was associated with 9 of 15 outcomes; BMI and systolic blood pressure were associated with 13 and 15 of 18 vascular outcomes, respectively; and fasting insulin was associated with 4 and fasting glucose with 2. No robust association was found for HbA1c instruments. With adjustment for correlated traits in the multivariable test, BMI and systolic blood pressure, consistent causal effects were maintained, while five associations with type 2 diabetes (chronic kidney disease, ischemic heart disease, heart failure, subarachnoid hemorrhage, and intracerebral hemorrhage) were attenuated to null. CONCLUSIONS Our findings add strong evidence to support the importance of BMI and systolic blood pressure in the development of vascular complications in people with type 2 diabetes. Such findings strongly support the need for better weight and blood pressure management in type 2 diabetes, independent of glucose lowering, to limit important complications.
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Affiliation(s)
- Altayeb Ahmed
- Centre for Inflammation Research and Translational Medicine, Department of Life Sciences, Brunel University London, London, U.K
| | - Hasnat Amin
- Centre for Inflammation Research and Translational Medicine, Department of Life Sciences, Brunel University London, London, U.K
| | - Fotios Drenos
- Centre for Inflammation Research and Translational Medicine, Department of Life Sciences, Brunel University London, London, U.K
| | - Naveed Sattar
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, U.K
| | - Hanieh Yaghootkar
- College of Health and Science, University of Lincoln, Lincoln, Lincolnshire, U.K
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