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Application guidelines

Research Projects at the Danish Twin Registry  


The Danish Twin Registry (DTR) is a national register and administered in accordance with the Processing of Personal Data Act.  The DTR covers twin births in Denmark since 1870.

The DTR is updated regularly with data from the national Health registries concerning vital status, addresses, hospitalizations, diagnoses, causes of death, and more. In addition, the DTR contains twin data from a large number of surveys and includes, for example, biological data (biomarkers) as well as objective measures for many twins.

DTR data are available to researchers with scientific research projects that have been approved by the DTR Scientific board, the Danish Data Protection Agency and/or the Committee on Biomedical Research Ethics.

The DTR scientific board decides on the form most suitable for each project, taking the DTR’s overall research plan into account. Unless otherwise agreed, a project’s duration will be no longer than 3 years.

For each research project, the DTR scientific board appoints a contact person from the board. This person normally will be a member of the project group.

Researchers wanting to use data or carry out projects at the DTR must submit an application, including a detailed study protocol. 

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Details in the form follow below:


The application must be 3-5 pages and contain the following information:

  1. General background (including relevant references to the literature cited)
  2. Purpose (including hypotheses)
  3. Description of the data applied for
  4. Outline of data management plan (i.e. How are the data to be handled during and after the project is completed? Which institution will be data controllers?  Which institution will be data processors?)
  5.  Research method(s)
    1. Questions (interview forms, if any, may be enclosed)
    2. Collection of biological material
  6. Types of analyses including discussion of required statistical power
    1. Analysis plan (who, how)
  7. The names of the research team including CV’s for the Principal Investigator (PI) and Project Leaders
  8. Co-operation plans and project time Schedule
  9. Publication plan
  10. Approval by the Danish Data Protection Agency and if requested the Danish Regional Committee on Biomedical Research Ethics
  11. Requested DTR resources: 
    1. Summary table(s) 
    2. Anonymous data
    3. Identifiable data (from own data collection) +/- biological samples
    4. Statistical instructions

The study must in all essentials keep to its protocol, and new studies may not be started without approval from the DTR scientific board.

When the study protocol is approved, the DTR-contact person will make arrangements regarding signing a Data Agreement on data access and transfer according to the DTR regulations.

Other terms

If a research project entails a collection of new data as a result of contact with the twins, the DTR must be informed of the following:

  • Participant status and his/her reason for non-participation
  • Zygosity diagnosis of twins participating in clinical studies, if such a diagnosis is not obtained in collaboration with the DTR management.

Contact with any twins beyond the time period described in the protocol must not take place until DTR approval has been obtained. 

Letters to twins must always include the co-signature of the project’s DTR contact person.

Questionnaire surveys must not contain more than one reminder notice to each potential participant unless otherwise agreed with the DTR scientific board and the Committee on Biomedical Research Ethics.

Data will generally be made available to researchers in anonymized form. Identification information may, however, be made available if contact with project participants is required. 

Biological material

If collection of biological material is part of the project, a sample can be given to the DTR for storage in the DTR biobank.


Biological material from twins can only be used for the purpose to which it has been collected unless the study participants have consented in allowing the use of their material in other research projects. In that case the biological material may be used in other projects after the conclusion of the original project, but only if approved by the DTR scientific board and the Committees on Biomedical Research Ethics.


Project conclusion

When the project is ended the research data (both personal data and biological material) can be stored at the DTR, with the DTR obtaining any approvals needed from the Danish Data Protection Agency. The storage of all data at DTR replaces the claim of data to be deleted/destroyed or anonymized in accordance with the guidelines of the Act on Processing of Personal Data (Act No. 429 of 31 May 2000) entered into force on 1 July 2000.

At project conclusion all collected data can be given to the DTR in order to ensure an optimal utilization of the data by the research community. This also applies to new scales or indices estimated on the basis of data from the DTR and used in published studies.

The research team has the right to use the data resulting from the project during the entire project period and three years after project conclusion. After this date, data that have been delivered to the DTR may be made available to other researchers through the DTR, but only after the DTR has advised the researchers who originally procured the data.

The DTR does not pass on to third parties data collected by or resulting from a research project as long as the research project is active. In general, information on zygosity, vital status, may be passed on to third party.

All manuscripts must be approved by the DTR-contact person before submission. The contact person must be given the opportunity to earn co-authorship on manuscripts derived from the project. The contact person is under obligation to comment on manuscripts within a reasonable time limit. A copy of the publications (including abstracts) resulting from the research project must be forwarded to the DTR.

The following credit line and disclaimer must be used on all reports, publications, and other materials resulting from use of the data:

“Data used for this research was provided by the Danish Twin Registry (DTR), University of Southern Denmark. The findings, opinions and recommendations expressed therein are those of the author(s) and are not necessarily those of the DTR.”


The costs of carrying out a project (including the costs of procuring data from the DTR) are covered by the project team. For each particular project, the project team and the DTR management will agree on the expenses in connection with procurement of data.


Management & Scientific Board

  • Director, Professor Kaare Christensen
  • External Professor Niels V. Holm
  • Professor Jacob v B. Hjelmborg
  • Professor Kirsten Ohm Kyvik
  • Associate Professor Christine Dalgård
  • Database Specialist Lars Hvidberg
  • Data Analyst Dorthe Almind Pedersen

The DTR scientific board meets every month to review project applications based on DTR resources and data.

Research Projects at the Danish Twin Registry

Please read our guidelines before applying for data access

Twin Data

Data available for scientific purposes

Research data

Project Application Form

How to apply?

Application Form