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Khouja JN, Sanderson E, Wootton RE, Taylor AE, Church BA, Richmond RC, Munafò MR. Estimating the health impact of nicotine exposure by dissecting the effects of nicotine versus non-nicotine constituents of tobacco smoke: A multivariable Mendelian randomisation study. PLoS Genet 2024; 20:e1011157. [PMID: 38335242 PMCID: PMC10883537 DOI: 10.1371/journal.pgen.1011157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 02/22/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024] Open
Abstract
The detrimental health effects of smoking are well-known, but the impact of regular nicotine use without exposure to the other constituents of tobacco is less clear. Given the increasing daily use of alternative nicotine delivery systems, such as e-cigarettes, it is increasingly important to understand and separate the effects of nicotine use from the impact of tobacco smoke exposure. Using a multivariable Mendelian randomisation framework, we explored the direct effects of nicotine compared with the non-nicotine constituents of tobacco smoke on health outcomes (lung cancer, chronic obstructive pulmonary disease [COPD], forced expiratory volume in one second [FEV-1], forced vital capacity [FVC], coronary heart disease [CHD], and heart rate [HR]). We used Genome-Wide Association Study (GWAS) summary statistics from Buchwald and colleagues, the GWAS and Sequencing Consortium of Alcohol and Nicotine, the International Lung Cancer Consortium, and UK Biobank. Increased nicotine metabolism increased the risk of COPD, lung cancer, and lung function in the univariable analysis. However, when accounting for smoking heaviness in the multivariable analysis, we found that increased nicotine metabolite ratio (indicative of decreased nicotine exposure per cigarette smoked) decreases heart rate (b = -0.30, 95% CI -0.50 to -0.10) and lung function (b = -33.33, 95% CI -41.76 to -24.90). There was no clear evidence of an effect on the remaining outcomes. The results suggest that these smoking-related outcomes are not due to nicotine exposure but are caused by the other components of tobacco smoke; however, there are multiple potential sources of bias, and the results should be triangulated using evidence from a range of methodologies.
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Affiliation(s)
- Jasmine N. Khouja
- School of Psychological Science, University of Bristol, Bristol, United Kingdom
- Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, United Kingdom
| | - Eleanor Sanderson
- Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, United Kingdom
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Robyn E. Wootton
- School of Psychological Science, University of Bristol, Bristol, United Kingdom
- Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, United Kingdom
- Nic Waals Institute, Lovisenberg diakonale sykehus, Oslo, Norway
| | - Amy E. Taylor
- Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, United Kingdom
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Billy A. Church
- School of Psychology and Vision Sciences, University of Leicester, United Kingdom
| | - Rebecca C. Richmond
- Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, United Kingdom
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Marcus R. Munafò
- School of Psychological Science, University of Bristol, Bristol, United Kingdom
- Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, United Kingdom
- NIHR Bristol Biomedical Research Centre, Bristol, United Kingdom
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Coman EN, Steinbach S, Cao G. Spatial perspectives in family health research. Fam Pract 2022; 39:556-562. [PMID: 34910138 DOI: 10.1093/fampra/cmab165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Emil N Coman
- University of Connecticut School of Medicine, Health Disparities Institute, Hartford, CT, United States
| | - Sandro Steinbach
- University of Connecticut, Department of Agricultural and Resource Economics, Storrs, CT, United States
| | - Guofeng Cao
- University of Colorado Boulder, Department of Geography, Boulder, CO, United States
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Sepriano A, Ramiro S, van der Heijde D, Landewé R. Biological DMARDs and disease modification in axial spondyloarthritis: a review through the lens of causal inference. RMD Open 2021; 7:rmdopen-2021-001654. [PMID: 34253683 PMCID: PMC8276290 DOI: 10.1136/rmdopen-2021-001654] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 06/30/2021] [Indexed: 12/15/2022] Open
Abstract
Axial spondyloarthritis (axSpA) is a chronic rheumatic disease characterised by inflammation predominantly involving the spine and the sacroiliac joints. In some patients, axial inflammation leads to irreversible structural damage that in the spine is usually quantified by the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS). Available therapeutic options include biological disease-modifying antirheumatic drugs (bDMARDs), which have been proven effective in suppressing inflammation in several randomised controlled trials (RCT), the gold standard for evaluating causal treatment effects. RCTs are, however, unfeasible for testing structural effects in axSpA mainly due to the low sensitivity to change of the mSASSS. The available literature therefore mainly includes observational research, which poses serious challenges to the determination of causality. Here, we review the studies testing the effect of bDMARDs on spinal radiographic progression, making use of the principles of causal inference. By exploring the assumptions of causality under counterfactual reasoning (exchangeability, positivity and consistency), we distinguish between studies that likely have reported confounded treatment effects and studies that, on the basis of their design, have more likely reported causal treatment effects. We conclude that bDMARDs might, indirectly, interfere with spinal radiographic progression in axSpA by their effect on inflammation. Innovations in imaging are expected, so that placebo-controlled trials can in the future become a reality. In the meantime, causal inference analysis using observational data may contribute to a better understanding of whether disease modification is possible in axSpA.
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Affiliation(s)
- Alexandre Sepriano
- Rheumatology, NOVA Medical School, Universidade Nova de Lisboa, Lisboa, Portugal .,Rheumatology, Leiden University Medical Center, Leiden, Netherlands
| | - Sofia Ramiro
- Rheumatology, Leiden University Medical Center, Leiden, Netherlands.,Rheumatology, Zuyderland Medical Centre Heerlen, Heerlen, Netherlands
| | | | - Robert Landewé
- Rheumatology, Zuyderland Medical Centre Heerlen, Heerlen, Netherlands.,Clinical Immunology and Rheumatology, Amsterdam University Medical Centres, Duivendrecht, Netherlands
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