Article open access publication

Investigating the causal effect of smoking on hay fever and asthma: a Mendelian randomization meta-analysis in the CARTA consortium

Scientific Reports, Springer Nature, ISSN 2045-2322

Volume 7, 1, 2017

DOI:10.1038/s41598-017-01977-w, Dimensions: pub.1085461702, PMC: PMC5440386, PMID: 28533558,

Affiliations

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  1. (1) Research Centre for Prevention and Health, Centre for Health, Capital Region of Denmark, Copenhagen, Denmark
  2. (2) University of Bristol, grid.5337.2
  3. (3) Steno Diabetes Center, grid.419658.7, Capital Region
  4. (4) Copenhagen Prospective Studies on Asthma in Childhood (COPSAC), Herlev and Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark
  5. (5) University of Copenhagen, grid.5254.6, KU
  6. (6) Copenhagen University Hospital, grid.4973.9, Capital Region
  7. (7) University of South Australia, grid.1026.5
  8. (8) MRC Unit for Lifelong Health and Ageing, grid.268922.5
  9. (9) Norwegian University of Science and Technology, grid.5947.f
  10. (10) St Olav's University Hospital, grid.52522.32
  11. (11) Helmholtz Zentrum München, grid.4567.0
  12. (12) National Institute for Health and Welfare, grid.14758.3f
  13. (13) University of Glasgow, grid.8756.c
  14. (14) University of Greifswald, grid.5603.0
  15. (15) Leiden University Medical Center, grid.10419.3d
  16. (16) King Faisal Specialist Hospital & Research Centre, grid.415310.2
  17. (17) Department of Pulmonary Medicine, Ruhrlandklinik, West German Lung Center, University Hospital Essen, University Duisburg-Essen, Essen, Germany
  18. (18) Helmsley Medical Centre, Helmsley, York, UK
  19. (19) Comprehensive Pneumology Center Munich (CPC-M), Member of the German Center for Lung Research, Munich, Germany
  20. (20) Institute of Genetic Epidemiology, Helmholtz Zentrum München – German Research Center for Environmental Health, Neuherberg, Germany
  21. (21) Ludwig Maximilian University of Munich, grid.5252.0
  22. (22) Institute of Human Genetics, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
  23. (23) Technical University of Munich, grid.6936.a
  24. (24) German Centre for Cardiovascular Research, grid.452396.f
  25. (25) Research Unit Molecular Epidemiology, Helmholtz Zentrum München – German Research Center for Environmental Health, Neuherberg, Germany
  26. (26) German Center for Diabetes Research, grid.452622.5
  27. (27) Institute of Epidemiology II, Helmholtz Zentrum München – German Research Center for Environmental Health, Neuherberg, Germany
  28. (28) University of Southern Denmark, grid.10825.3e, SDU
  29. (29) University College London, grid.83440.3b
  30. (30) University of Essex, grid.8356.8
  31. (31) South Australian Health and Medical Research Institute, grid.430453.5
  32. (32) Aalborg University, grid.5117.2, AAU
  33. (33) University of Helsinki, grid.7737.4
  34. (34) Rigshospitalet, grid.475435.4, Capital Region

Description

Observational studies on smoking and risk of hay fever and asthma have shown inconsistent results. However, observational studies may be biased by confounding and reverse causation. Mendelian randomization uses genetic variants as markers of exposures to examine causal effects. We examined the causal effect of smoking on hay fever and asthma by using the smoking-associated single nucleotide polymorphism (SNP) rs16969968/rs1051730. We included 231,020 participants from 22 population-based studies. Observational analyses showed that current vs never smokers had lower risk of hay fever (odds ratio (OR) = 0·68, 95% confidence interval (CI): 0·61, 0·76; P < 0·001) and allergic sensitization (OR = 0·74, 95% CI: 0·64, 0·86; P < 0·001), but similar asthma risk (OR = 1·00, 95% CI: 0·91, 1·09; P = 0·967). Mendelian randomization analyses in current smokers showed a slightly lower risk of hay fever (OR = 0·958, 95% CI: 0·920, 0·998; P = 0·041), a lower risk of allergic sensitization (OR = 0·92, 95% CI: 0·84, 1·02; P = 0·117), but higher risk of asthma (OR = 1·06, 95% CI: 1·01, 1·11; P = 0·020) per smoking-increasing allele. Our results suggest that smoking may be causally related to a higher risk of asthma and a slightly lower risk of hay fever. However, the adverse events associated with smoking limit its clinical significance.

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University of Copenhagen

University of Southern Denmark

Aalborg University

Danish Open Access Indicator

2017: Realized

Research area: Medicine

Danish Bibliometrics Indicator

2017: Level 1

Research area: Medicine

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Times Cited: 13

Field Citation Ratio (FCR): 5.47

Relative Citation ratio (RCR): 1.05

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