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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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Tada S, Tsuihiji T, Matsumoto R, Hanai T, Iwami Y, Tomita N, Sato H, Tsogtbaatar K. Evolutionary process toward avian-like cephalic thermoregulation system in Theropoda elucidated based on nasal structures. R Soc Open Sci 2023; 10:220997. [PMID: 37063996 PMCID: PMC10090882 DOI: 10.1098/rsos.220997] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 03/15/2023] [Indexed: 06/19/2023]
Abstract
It has long been discussed whether non-avian dinosaurs were physiologically closer to ectotherms or endotherms, with the internal nasal structure called the respiratory turbinate present in extant endotherms having been regarded as an important clue for this conundrum. However, the physiological function and relevance of this structure for dinosaur physiology are still controversial. Here, we found that the size of the nasal cavity relative to the head size of extant endotherms is larger than those of extant ectotherms, with that of the dromaeosaurid Velociraptor being below the extant endotherms level. The result suggests that a large nasal cavity accommodating a well-developed respiratory turbinate is primarily important as a thermoregulation apparatus for large brains characteristic of endothermic birds and mammals, and the nasal cavity of Velociraptor was apparently not large enough to carry out this role required for an endothermic-sized brain. In addition, a hypothesis that the enlargement of the nasal cavity for brain cooling has been associated with the skull modification in the theropod lineage toward modern birds is proposed herein. In particular, the reduction of the maxilla in derived avialans may have coincided with acquisition of the avian-like cephalic thermoregulation system.
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Affiliation(s)
- Seishiro Tada
- Department of Geology and Paleontology, National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba, Ibaraki 305-0005, Japan
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takanobu Tsuihiji
- Department of Geology and Paleontology, National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba, Ibaraki 305-0005, Japan
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ryoko Matsumoto
- Department of Zoology, Kanagawa Prefectural Museum of Natural History, 499 Iryuda, Odawara, Kanagawa 250-0031, Japan
| | - Tomoya Hanai
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yasuko Iwami
- Yamashina Institute for Ornithology, 115 Konoyama, Abiko, Chiba 270-1145, Japan
| | - Naoki Tomita
- Yamashina Institute for Ornithology, 115 Konoyama, Abiko, Chiba 270-1145, Japan
| | - Hideaki Sato
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- The University Museum, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Khishigjav Tsogtbaatar
- Institute of Paleontology and Geology, Mongolian Academy of Sciences, 15160 Ulaanbaatar, Mongolia
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