Skip to main content

The Danish Civil Registration System as a tool in epidemiology

European Journal of Epidemiology volume 29, pages 541–549 (2014)Cite this article

Abstract

The methodological advances in epidemiology have facilitated the use of the Danish Civil Registration System (CRS) in ways not previously described systematically. We reviewed the CRS and its use as a research tool in epidemiology. We obtained information from the Danish Law on Civil Registration and the Central Office of Civil Registration, and used existing literature to provide illustrative examples of its use. The CRS is an administrative register established on April 2, 1968. It contains individual-level information on all persons residing in Denmark (and Greenland as of May 1, 1972). By January 2014, the CRS had cumulatively registered 9.5 million individuals and more than 400 million person-years of follow-up. A unique ten-digit Civil Personal Register number assigned to all persons in the CRS allows for technically easy, cost-effective, and unambiguous individual-level record linkage of Danish registers. Daily updated information on migration and vital status allows for nationwide cohort studies with virtually complete long-term follow-up on emigration and death. The CRS facilitates sampling of general population comparison cohorts, controls in case–control studies, family cohorts, and target groups in population surveys. The data in the CRS are virtually complete, have high accuracy, and can be retrieved for research purposes while protecting the anonymity of Danish residents. In conclusion, the CRS is a key tool for epidemiological research in Denmark.

This is a preview of subscription content, access via your institution.

Access options

Buy single article

Instant access to the full article PDF.

43,34 €

Price includes VAT (Finland)
Tax calculation will be finalised during checkout.

Fig. 1
Fig. 2
Fig. 3
Fig. 4

References

  1. Sørensen HT. Regional administrative health registries as a resource in clinical epidemiology: a study of options, strengths, limitations and data quality provided with examples of use. Int J Risk Saf Med. 1997;10:1–22.

    PubMed  Google Scholar 

  2. Epidemiology FL. When an entire country is a cohort. Science. 2000;287:2398–9.

    Article  Google Scholar 

  3. Ministry of Interior and Health. Health Care in Denmark. 2008. http://www.sum.dk/Aktuelt/Publikationer/~/media/Filer%20-%20Publikationer_i_pdf/2008/UK_Healthcare_in_dk/pdf.ashx. Accessed 1 Dec 2013.

  4. Malig C. The Civil Registration System in Denmark. Technical Papers IIVRS. 1996;66:1–6.

  5. Willumsen H. The Civil registration—75 years in 1999 (in Danish: Folkeregistreringen 75 år i 1999). The CPR Office. 1999.

  6. Nielsen H. CPR—the Danish Civil Registration System (in Danish: CPR—Danmarks Folkeregister). The CPR Office. 1991.

  7. The CPR Office. About the CPR Office. www.cpr.dk/om-cpr-kontoret. Accessed 1 Dec 2013.

  8. The Ministry of Economic Affairs and the Interior. The CPR law (in Danish: CPR-loven). Dated 9 January 2013. www.retsinformation.dk/Forms/R0710.aspx?id=144955. Accessed 1 Dec 2013.

  9. The CPR Office. Data provided by the CPR Office on request. 2014.

  10. Ludvigsson JF, Otterblad-Olausson P, Pettersson BU, Ekbom A. The Swedish personal identity number: possibilities and pitfalls in healthcare and medical research. Eur J Epidemiol. 2009;24:659–67.

    PubMed Central  PubMed  Article  Google Scholar 

  11. The CPR Office. Structure of the CPR number (in Danish: Opbygning af cpr-nummeret). https://cpr.dk/cpr-systemet/opbygning-af-cpr-nummeret/. Accessed 1 Dec 2013.

  12. The Ministry of Economic Affairs and the Interior. Proposal to revise the CPR law (in Danish: Forslag til Lov om ændring af lov om Det Centrale Personregister). Dated 15 January 2014. www.retsinformation.dk/Forms/R0710.aspx?id=162326. Accessed 2 June 2014.

  13. Wildenschild C, Mehnert F, Thomsen RW, Iversen HK, Vestergaard K, Ingeman A, et al. Registration of acute stroke: validity in the Danish Stroke Registry and the Danish National Registry of Patients. Clin Epidemiol. 2013;6:27–36.

    PubMed Central  PubMed  Article  Google Scholar 

  14. Stephansson O, Kieler H, Haglund B, Artama M, Engeland A, Furu K, et al. Selective serotonin reuptake inhibitors during pregnancy and risk of stillbirth and infant mortality. JAMA. 2013;309:48–54.

    CAS  PubMed  Article  Google Scholar 

  15. Furu K, Wettermark B, Andersen M, Martikainen JE, Almarsdottir AB, Sørensen HT. The Nordic countries as a cohort for pharmacoepidemiological research. Basic Clin Pharmacol Toxicol. 2010;106:86–94.

    CAS  PubMed  Article  Google Scholar 

  16. Li J, Vestergaard M, Obel C, Cnattingus S, Gissler M, Olsen J. Cohort profile: the Nordic perinatal bereavement cohort. Int J Epidemiol. 2011;40:1161–7.

    PubMed  Article  Google Scholar 

  17. Sørensen HT, Thulstrup AM, Blomqvist P, Nørgaard B, Fonager K, Ekbom A. Risk of primary biliary liver cirrhosis in patients with coeliac disease: Danish and Swedish cohort data. Gut. 1999;44:736–8.

    PubMed Central  PubMed  Article  Google Scholar 

  18. Momen N, Olsen J, Gissler M, Cnattingius S, Li J. Delivery by caesarean section and childhood cancer: a nationwide follow-up study in three countries. BJOG. 2014. doi:10.1111/1471-0528.12667.

  19. Schmidt M, Bøtker HE, Pedersen L, Sørensen HT. Comparison of the frequency of atrial fibrillation in young obese versus young nonobese men undergoing examination for fitness for military service. Am J Cardiol. 2014;113:822–6.

    PubMed  Article  Google Scholar 

  20. Schmidt M, Jacobsen JB, Johnsen SP, Bøtker HE, Sørensen HT. Eighteen-year trends in stroke mortality and the prognostic influence of comorbidity. Neurology. 2014;82:340–50.

    PubMed  Article  Google Scholar 

  21. Thuesen L, Jensen LO, Tilsted HH, Maeng M, Terkelsen C, Thayssen P, et al. Event detection using population-based health care databases in randomized clinical trials: a novel research tool in interventional cardiology. Clin Epidemiol. 2013;5:357–61.

    PubMed Central  PubMed  Article  Google Scholar 

  22. Hordijk-Trion M. Patients enrolled in coronary intervention trials are not representative of patients in clinical practice: results from the Euro Heart Survey on Coronary Revascularization. Eur Heart J. 2006;27:671–8.

    PubMed  Article  Google Scholar 

  23. Christiansen EH, Jensen LO, Thayssen P, Tilsted HH, Krusell LR, Hansen KN, et al. Biolimus-eluting biodegradable polymer-coated stent versus durable polymer-coated sirolimus-eluting stent in unselected patients receiving percutaneous coronary intervention (SORT OUT V): a randomised non-inferiority trial. Lancet. 2013;381:661–9.

    CAS  PubMed  Article  Google Scholar 

  24. Nielsen PH, Maeng M, Busk M, Mortensen LS, Kristensen SD, Nielsen TT, et al. Primary angioplasty versus fibrinolysis in acute myocardial infarction: long-term follow-up in the Danish acute myocardial infarction 2 trial. Circulation. 2010;121:1484–91.

    PubMed  Article  Google Scholar 

  25. Sloth AD, Schmidt MR, Munk K, Kharbanda RK, Redington AN, Schmidt M et al. Improved long-term clinical outcomes in patients with ST-elevation myocardial infarction undergoing remote ischaemic conditioning as an adjunct to primary percutaneous coronary intervention. Eur Heart J. 2013;35:168–175.

  26. Jespersen CM, Als-Nielsen B, Damgaard M, Hansen JF, Hansen S, Helø OH, et al. Randomised placebo controlled multicentre trial to assess short term clarithromycin for patients with stable coronary heart disease: CLARICOR trial. BMJ. 2006;332:22–7.

    PubMed Central  PubMed  Article  Google Scholar 

  27. Schmidt M, Pedersen L, Maeng M, Lassen JF, Lash TL, Nielsen TT, et al. Nonsteroidal antiinflammatory drug use and cardiovascular risks after coronary stent implantation. Pharmacotherapy. 2011;31:458–68.

    PubMed  Article  Google Scholar 

  28. Schmidt M, Jacobsen JB, Lash TL, Bøtker HE, Sørensen HT. 25 year trends in first time hospitalisation for acute myocardial infarction, subsequent short and long term mortality, and the prognostic impact of sex and comorbidity: a Danish nationwide cohort study. BMJ. 2012;344:e356.

  29. Pedersen AB, Johnsen SP, Sørensen HT. Increased one-year risk of symptomatic venous thromboembolism following total hip replacement. J Bone Joint Surg Br. 2012;94:1598–1603.

  30. Sørensen HT, Mellemkjær L, Olsen JH, Baron JA. Prognosis of cancers associated with venous thromboembolism. N Engl J Med. 2000;343:1846–50.

    PubMed  Article  Google Scholar 

  31. Rothman KJ, Greenland S, Lash TL. Case–control studies. In: Rothman KJ, Greenland S, Lash TL, editors. Modern epidemiology. 3rd ed. Philadelphia: Lippincott Williams & Wilkins; 2008. p. 124–5.

    Google Scholar 

  32. Schmidt M, Christiansen CF, Mehnert F, Rothman KJ, Sørensen HT. Non-steroidal anti-inflammatory drug use and risk of atrial fibrillation or flutter: population based case-control study. BMJ. 2011;343:d3450.

    PubMed  Article  Google Scholar 

  33. Christiansen CF, Christensen S, Mehnert F, Cummings SR, Chapurlat RD, Sørensen HT. Glucocorticoid use and risk of atrial fibrillation or flutter: a population-based, case–control study. Arch Intern Med. 2009;169:1677–83.

    PubMed  Article  Google Scholar 

  34. Andersen EW. Family studies based on routine register data. PhD dissertation. University of Copenhagen. 2002.

  35. Danish Serum Institute. About the Danish Family Relations Database. http://www.ssi.dk/Forskning/Forskningsomraader/Epidemiologi/Sygdommes%20arvelighed.aspx. Accessed 1 Feb 2014.

  36. Ranthe MF, Winkel BG, Andersen EW, Risgaard B, Wohlfahrt J, Bundgaard H, et al. Risk of cardiovascular disease in family members of young sudden cardiac death victims. Eur Heart J. 2013;34:503–11.

    PubMed  Article  Google Scholar 

  37. Christensen K, Schmidt MM, Vaeth M, Olsen J. Absence of an environmental effect on the recurrence of facial-cleft defects. N Engl J Med. 1995;333:161–4.

    CAS  PubMed  Article  Google Scholar 

  38. Krogh C, Fischer TK, Skotte L, Biggar RJ, Øyen N, Skytthe A, et al. Familial aggregation and heritability of pyloric stenosis. JAMA. 2010;303:2393–9.

    CAS  PubMed  Article  Google Scholar 

  39. Center for Public Health and Quality Improvement, Central Denmark Region. How Are You? (in Danish: Hvordan har du det?). www.cfk.rm.dk/udgivelser/befolkningsundersøgelser. Accessed 1 Feb 2014.

  40. Thomsen RW, Nielsen RB, Nørgaard M, Horsdal HT, Til S, Larsen FB, et al. Lifestyle profile among statin users. Epidemiology. 2013;24:619–20.

    PubMed  Article  Google Scholar 

  41. Christensen AI, Ekholm O, Glümer C, Andreasen AH, Hvidberg MF, Kristensen PL, The Danish National Health Survey, et al. Study design and respondent characteristics. Scand J Public Health. 2010;2012(40):391–7.

    Google Scholar 

  42. Eriksen L, Grønbaek M, Helge JW, Tolstrup JS, Curtis T. The Danish Health Examination Survey 2007–2008 (DANHES 2007–2008). Scand J Public Health. 2011;39:203–11.

    PubMed  Article  Google Scholar 

  43. Fangel S, Linde PC, Thorsted BL. New problems with survey representativity, which enumeration with registers is able to reduce (in Danish: Nye problemer med repræsentativitet i surveys, som opregning med registre kan reducere). Metode og Data. 2007;93:14–26.

    Google Scholar 

  44. Höfler M, Pfister H, Lieb R, Wittchen H-U. The use of weights to account for non-response and drop-out. Soc Psychiatry Psychiatr Epidemiol. 2005;40:291–9.

    PubMed  Article  Google Scholar 

  45. The CPR Office. The CPR number in the Danish Civil Registration System (in Danish: Personnummeret i CPR-systemet). www.cpr.dk/media/167692/personnummeret%20i%20cpr.pdf. Accessed 1 Dec 2013.

  46. Validate CPR numbers online (Danish). www.cpr-validering.dk. Accessed 1 Dec 2013.

  47. Danish Data Protection Agency. The Danish Act on Processing of Personal Data. www.datatilsynet.dk/english/the-act-on-processing-of-personal-data/. Accessed 1 Dec 2013.

  48. Danish Data Protection Agency. About the Danish Data Protection Agency. www.datatilsynet.dk/english. Accessed 1 Dec 2013.

  49. The National Committee on Health Research Ethics. About the National Committee on Health Research Ethics. www.dnvk.dk/CVK/home/english.aspx. Accessed 1 Dec 2013.

  50. Danish Health and Medicines Authority. Forskerservice. www.ssi.dk/Sundhedsdataogit/Forskerservice.aspx. Accessed 1 Dec 2013.

Download references

Acknowledgments

The Department of Clinical Epidemiology, Aarhus University Hospital, receives funding for other studies from companies in the form of research grants to (and administered by) Aarhus University. None of the company-funded studies have any relation to the present study. The study was supported by Aarhus University Research Foundation.

Ethical standard

As the research reported in this paper did not involve any contact with patients or any intervention, it was not necessary to obtain permission from the Danish Scientific Ethics Committee.

Conflicts of interest

The authors declare that they have no conflicts of interest.

Author information

Affiliations

  1. Department of Clinical Epidemiology, Aarhus University Hospital, Olof Palmes Allé 43-45, 8200, Aarhus N, Denmark

    Morten Schmidt, Lars Pedersen & Henrik Toft Sørensen

Authors
  1. Morten Schmidt
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Lars Pedersen
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Henrik Toft Sørensen
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Morten Schmidt.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Schmidt, M., Pedersen, L. & Sørensen, H.T. The Danish Civil Registration System as a tool in epidemiology. Eur J Epidemiol 29, 541–549 (2014). https://doi.org/10.1007/s10654-014-9930-3

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10654-014-9930-3

Keywords

  • Database
  • Registers
  • Epidemiology
  • Epidemiological methods
  • Data linkage
  • Follow-up