Relative importance of genetic effects in rheumatoid arthritis: historical cohort study of Danish nationwide twin populationCommentary: Do genes or environment influence development of rheumatoid arthritis?
BMJ 2002; 324 doi: https://doi.org/10.1136/bmj.324.7332.264 (Published 02 February 2002) Cite this as: BMJ 2002;324:264
- Anders J Svendsen, specialist registrar (a.svendsen{at}winsloew.ou.dk)a,
- Niels V Holm, associate professorb,
- Kirsten Kyvik, associate professorc,
- Per Hyltoft Petersen, master of scienced,
- Peter Junker, professora
- a Department of Rheumatology, Odense University Hospital, 5000 Odense C, Denmark,
- b Department of Radiotherapy and Clinical Oncology, Odense University Hospital,
- c Danish Twin Registry, Department of Public Health, Epidemiology, University of Southern Denmark, Denmark,
- d Department of Clinical Chemistry, Odense University Hospital
- ARC Epidemiology Unit, Manchester University Medical School, Manchester M13 9PT
- Accepted 1 October 2001
Abstract
Objective: To determine the relative importance of environmental and genetic effects in the development of rheumatoid arthritis.
Design: Historical cohort study with record linkage between a twin registry and the Danish discharge registry as well as the Danish national registry of deaths used to estimate completeness.
Setting: Two population based nationwide twin birth cohorts.
Participants: 37 338 twins were sent a questionnaire about rheumatic diseases. Self reported rheumatoid arthritis was verified by clinical examination and from medical records.
Main outcome measures: The probandwise concordance rate of rheumatoid arthritis in monozygotic and dizygotic twins.
Results: The response rate was 84.7%. Rheumatoid arthritis was verified in 13 monozygotic and 36 dizygotic twins. There were no concordant monozygotic twin pairs and two concordant dizygotic twin pairs. Based on capture-recapture methods the probability of ascertainment was 78.3%. The probandwise concordance rate was 0 (95% confidence interval 0 to 24.7) in monozygotic twins and 8.8 (1.9 to 23.7) in dizygotic twins.
Conclusion: Genes are of minor importance in the development of rheumatoid arthritis.
What is already known on this topic
What is already known on this topic Rheumatoid arthritis is a multifactorial disease determined by both genetic and environmental factors
Previous twin studies have shown a higher concordance for rheumatoid arthritis in monozygotic than in dizygotic twins, but the results have been biased in favour of genetic effects
What this paper adds
What this paper adds As concordance for rheumatoid arthritis in this study was no more common in monozygotic twins than in dizygotic twins environmental effects may be more important than genetic effects in the development of rheumatoid arthritis
Footnotes
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Funding Danish Rheumatism Association; Clinical Institute, Odense University; Karen Hansens Foundation; Danish Medical Association's Research Foundation; K⊘bmand Hans Christensens Foundation; Grosserer Valdemar Foersom og hustru Thyra Foersom, f⊘dt Otto's Foundation; Henny og Helge Holgersens Foundation; Ingemann O Buck's Foundation; Ingeni⊘r af Frederikssund S⊘ren Alfred Andersen's Foundation.
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Competing interests None declared.
- Accepted 1 October 2001
Commentary: Do genes or environment influence development of rheumatoid arthritis?
- Alan J Silman, professor (a.silman{at}man.ac.uk)
- a Department of Rheumatology, Odense University Hospital, 5000 Odense C, Denmark,
- b Department of Radiotherapy and Clinical Oncology, Odense University Hospital,
- c Danish Twin Registry, Department of Public Health, Epidemiology, University of Southern Denmark, Denmark,
- d Department of Clinical Chemistry, Odense University Hospital
- ARC Epidemiology Unit, Manchester University Medical School, Manchester M13 9PT
Footnotes
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Competing interests None declared.