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Butler-Laporte G, Farjoun Y, Chen Y, Hultström M, Liang KYH, Nakanishi T, Su CY, Yoshiji S, Forgetta V, Richards JB. Increasing serum iron levels and their role in the risk of infectious diseases: a Mendelian randomization approach. Int J Epidemiol 2023; 52:1163-1174. [PMID: 36773317 PMCID: PMC10396421 DOI: 10.1093/ije/dyad010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 02/02/2023] [Indexed: 02/13/2023] Open
Abstract
OBJECTIVES Increased iron stores have been associated with elevated risks of different infectious diseases, suggesting that iron supplementation may increase the risk of infections. However, these associations may be biased by confounding or reverse causation. This is important, since up to 19% of the population takes iron supplementation. We used Mendelian randomization (MR) to bypass these biases and estimate the causal effect of iron on infections. METHODS As instrumental variables, we used genetic variants associated with iron biomarkers in two genome-wide association studies (GWASs) of European ancestry participants. For outcomes, we used GWAS results from the UK Biobank, FinnGen, the COVID-19 Host Genetics Initiative or 23andMe, for seven infection phenotypes: 'any infections', combined, COVID-19 hospitalization, candidiasis, pneumonia, sepsis, skin and soft tissue infection (SSTI) and urinary tract infection (UTI). RESULTS Most of our analyses showed increasing iron (measured by its biomarkers) was associated with only modest changes in the odds of infectious outcomes, with all 95% odds ratios confidence intervals within the 0.88 to 1.26 range. However, for the three predominantly bacterial infections (sepsis, SSTI, UTI), at least one analysis showed a nominally elevated risk with increased iron stores (P <0.05). CONCLUSION Using MR, we did not observe an increase in risk of most infectious diseases with increases in iron stores. However for bacterial infections, higher iron stores may increase odds of infections. Hence, using genetic variation in iron pathways as a proxy for iron supplementation, iron supplements are likely safe on a population level, but we should continue the current practice of conservative iron supplementation during bacterial infections or in those at high risk of developing them.
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Affiliation(s)
- Guillaume Butler-Laporte
- Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC, Canada
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montréal, QC, Canada
| | - Yossi Farjoun
- Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC, Canada
| | - Yiheng Chen
- Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC, Canada
| | - Michael Hultström
- Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC, Canada
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montréal, QC, Canada
- Anaesthesiology and Intensive Care Medicine, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
- Integrative Physiology, Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Kevin Y H Liang
- Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC, Canada
| | - Tomoko Nakanishi
- Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC, Canada
- Department of Human Genetics, McGill University, Montréal, QC, Canada
- Kyoto-McGill International Collaborative School in Genomic Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Chen-Yang Su
- Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC, Canada
| | - Satoshi Yoshiji
- Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC, Canada
- Kyoto-McGill International Collaborative School in Genomic Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Vincenzo Forgetta
- Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC, Canada
| | - J Brent Richards
- Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC, Canada
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montréal, QC, Canada
- Department of Human Genetics, McGill University, Montréal, QC, Canada
- Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
- Department of Twin Research, King’s College London, London, UK
- 5 Prime Sciences Inc., Montreal, QC, Canada
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Freidin MB, Stalteri MA, Wells PM, Lachance G, Baleanu AF, Bowyer RCE, Kurilshikov A, Zhernakova A, Steves CJ, Williams FMK. An association between chronic widespread pain and the gut microbiome. Rheumatology (Oxford) 2021; 60:3727-3737. [PMID: 33331911 PMCID: PMC8328510 DOI: 10.1093/rheumatology/keaa847] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 11/12/2020] [Indexed: 01/04/2023] Open
Abstract
OBJECTIVES Chronic widespread musculoskeletal pain (CWP) is a characteristic symptom of fibromyalgia, which has been shown to be associated with an altered gut microbiome. Microbiome studies to date have not examined the milder CWP phenotype specifically nor have they explored the role of raised BMI. The aim of this study was to investigate whether the microbiome is abnormal in CWP. METHODS CWP was assessed using a standardized screening questionnaire in female volunteers from the TwinsUK cohort including 113 CWP cases and 1623 controls. The stool microbiome was characterized using 16S rRNA amplicon sequencing and amplicon sequence variants, and associations with CWP examined using linear mixed-effects models adjusting for BMI, age, diet, family relatedness and technical factors. RESULTS Alpha diversity was significantly lower in CWP cases than controls (Mann-Whitney test, P-values 2.3e-04 and 1.2e-02, for Shannon and Simpson indices respectively). The species Coprococcus comes was significantly depleted in CWP cases (Padj = 3.04e-03). A genome-wide association study (GWAS) performed for C. comes in TwinsUK followed by meta-analysis with three Dutch cohorts (total n = 3521) resulted in nine suggestive regions, with the most convincing on chromosome 4 near the TRAM1L1 gene (rs76957229, P = 7.4e-8). A Mendelian randomization study based on the results of the GWAS did not support a causal role for C. comes on the development of CWP. CONCLUSIONS We have demonstrated reduced diversity in the microbiome in CWP, indicating an involvement of the gut microbiota in CWP; prospectively the microbiome may offer therapeutic opportunities for this condition.
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Affiliation(s)
- Maxim B Freidin
- Department of Twin Research and Genetic Epidemiology, School of Life Course Sciences, King's College London, London, UK
| | - Maria A Stalteri
- Department of Twin Research and Genetic Epidemiology, School of Life Course Sciences, King's College London, London, UK
| | - Philippa M Wells
- Department of Twin Research and Genetic Epidemiology, School of Life Course Sciences, King's College London, London, UK
| | - Genevieve Lachance
- Department of Twin Research and Genetic Epidemiology, School of Life Course Sciences, King's College London, London, UK
| | - Andrei-Florin Baleanu
- Department of Twin Research and Genetic Epidemiology, School of Life Course Sciences, King's College London, London, UK
| | - Ruth C E Bowyer
- Department of Twin Research and Genetic Epidemiology, School of Life Course Sciences, King's College London, London, UK
| | - Alexander Kurilshikov
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Alexandra Zhernakova
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Claire J Steves
- Department of Twin Research and Genetic Epidemiology, School of Life Course Sciences, King's College London, London, UK
| | - Frances M K Williams
- Department of Twin Research and Genetic Epidemiology, School of Life Course Sciences, King's College London, London, UK
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Cecelja M, Keehn L, Ye L, Spector TD, Hughes AD, Chowienczyk P. Genetic aetiology of blood pressure relates to aortic stiffness with bi-directional causality: evidence from heritability, blood pressure polymorphisms, and Mendelian randomization. Eur Heart J 2020; 41:3314-3322. [PMID: 32357239 PMCID: PMC7544538 DOI: 10.1093/eurheartj/ehaa238] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 11/08/2019] [Accepted: 03/18/2020] [Indexed: 11/13/2022] Open
Abstract
AIMS Haemodynamic determinants of blood pressure (BP) include cardiac output (CO), systemic vascular resistance (SVR), and arterial stiffness. We investigated the heritability of these phenotypes, their association with BP-related single-nucleotide polymorphisms (SNPs), and the causal association between BP and arterial stiffness. METHODS AND RESULTS We assessed BP, central BP components, and haemodynamic properties (during a single visit) including CO, SVR, and pulse wave velocity (PWV, measure of arterial stiffness) in 3531 (1934 monozygotic, 1586 dizygotic) female TwinsUK participants. Heritability was estimated using structural equation modelling. Association with 984 BP-associated SNP was examined using least absolute shrinkage and selection operator (LASSO) and generalized estimating equation regression. One and two-sample Mendelian randomization (MR) was used to estimate the causal direction between BP and arterial stiffness including data on 436 419 UK Biobank participants. We found high heritability for systolic and pulsatile components of BP (>50%) and PWV (65%) with overlapping genes accounting for >50% of their observed correlation. Environmental factors explained most of the variability of CO and SVR (>80%). Regression identified SNPs (n = 5) known to be associated with BP to also be associated with PWV. One-sample MR showed evidence of bi-directional causal association between BP and PWV in TwinsUK participants. Two-sample MR, confirmed a bi-directional causal effect of PWV on BP (inverse variance weighted (IVW) beta = 0.11, P < 0.02) and BP on arterial stiffness (IVW beta = 0.004, P < 0.0001). CONCLUSION The genetic basis of BP is mediated not only by genes regulating BP but also by genes that influence arterial stiffness. Mendelian randomization indicates a bi-directional causal association between BP and arterial stiffness.
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Affiliation(s)
- Marina Cecelja
- Cardiovascular Division, Department of Clinical Pharmacology, King’s College London British Heart Foundation Centre, St Thomas’ Hospital, Westminster Bridge Road, London SE1 7EH, UK
| | - Louise Keehn
- Cardiovascular Division, Department of Clinical Pharmacology, King’s College London British Heart Foundation Centre, St Thomas’ Hospital, Westminster Bridge Road, London SE1 7EH, UK
| | - Li Ye
- Cardiovascular Division, Department of Clinical Pharmacology, King’s College London British Heart Foundation Centre, St Thomas’ Hospital, Westminster Bridge Road, London SE1 7EH, UK
| | - Tim D Spector
- Department of Twin Research and Genetic Epidemiology, King’s College London, St Thomas’ Hospital, Westminster Bridge Road, London SE1 7EH, UK
| | - Alun D Hughes
- Department of Population Science and Experimental Medicine, Institute of Cardiovascular Sciences, University College London, 69 Chenies Mews, London W1T 7HA, UK
| | - Phil Chowienczyk
- Cardiovascular Division, Department of Clinical Pharmacology, King’s College London British Heart Foundation Centre, St Thomas’ Hospital, Westminster Bridge Road, London SE1 7EH, UK
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