Swedish Twin Registry: For researchers

The Swedish Twin registry is an (inter)national resource. Data from the registry can become available to academic and industry-based researchers. Read more below what is required to initiate research with the Swedish Twin Registry.

KI uses a web based application routine for all core facilities. Please see specific instructions for the Twin Registry on this page.

Regardless of the type of research interest, all potential collaborations or data access agreements must first be reviewed by the steering committee of the STR.

Application procedure to utilize the Swedish Twin Registry

Policy and conditions

The general conditions for collaboration with the Swedish Twin Registry can be found in our policy document. Start the process by reading the policy document so that all conditions can be met. The STR expert committee meets four times per year and decides on all requests.

In order to process your request, a complete application must be received by the STR ​​no later than nine days before an expert committee meeting. For more information, please contact us by e-mail to str-research@meb.ki.se.

Dates for Expert Committee meetings 2024

  • 15/2 (deadline to apply before the meeting is 6/2)
  • 2/5 (deadline to apply before the meeting is 23/4)
  • 12/9 (deadline to apply before the meeting is 3/9)
  • 5/12 (deadline to apply before the meeting is 26/11)


Services and pricelist

How to apply

To be complete, an application must contain the following:

Step 1: prepare documents

  1. A detailed and complete description of the project comprising 3-5 pages, including:
    a) specific aims
    b) general background (including relevant literature references)
    c) requested variables with inclusion and exclusion criteria
    d) methods
    e) description of the research group
  2. CV of the PI (Principal Investigator)
  3. Ethical application and ethical approval (for projects not including new contacts). For projects in which contacts with study persons are to be made, it is recommended that the STR steering committee reviews both contact letters and informed consent formulations before these documents are sent for ethical review.

Step 2: web application - NEW WEB BASED ROUTINE!

  1. Go to the web-based tool for KI core facilities iLab, and register or login.
  2. Fill out the STR application form and attach the relevant documents (from step 1-3 above).

Step 3: after approval

If your application is approved, see guidelines for required data specifications.

Support on how to register and use iLab:

For those working at Karolinska Institutet: https://staff.ki.se/media/63145/download

For all other users: https://staff.ki.se/media/102125/download

Support pages for iLab: https://help.ilab.agilent.com/37179-using-a-core/264646-using-a-core-overview

Studies within the Swedish Twin Registry

In the STR dataportal you can search for metadata included in our cohorts and studies as well as create and download your own variable list: https://strdata.se/

Below you can find some information about our studies grouped by cohorts.

The information comprises:

Questionnaire, a PDF format file (Swedish only, when applicable)
Area of study, variables, codes an Excel format file

All files are password protected.

Contact the Twin Registry to obtain the password by e-mail to str-research@meb.ki.se.

Questionnaires administered in the 60s and the 70s with variable description

Born 1886-1925 Questionnaire 1961

Qustionnaire Q61 ( Swedish only)

Area of study, variables, codes

Born 1886-1925 Questionnaire 1963

Questionnaire Q63

Area of study, variables, codes

Born 1886-1925 Questionnaire 1967

Questionnaire Q67

Area of study, variables, codes

Born 1886-1925 Questionnaire 1970

Questionnaire Q70

Area of study, variables, codes

Born 1826-1958 Questionnaire 1973

Questionnaire Q73 (Swedish only)

Area of study, variables, codes

Questionnaires administered in the 90s with variable description

Born 1886-1958 SALT - Screening Across the Lifespan Twin

SALT Interview

SALT Area of study, variables, codes

Born 1886-1958 TwinGene - Pair of twins from the SALT-study

TwinGene Health questionnaire

TwinGene Health check up

TwinGene area of study, variables, codes

Born 1944-1958 SALTY - Screening Across the Lifespan Twin Young

SALTY man questionnaire (Swedish only)

SALTY woman questionnaire (Swedish only)

SALTY area of study, questionnaire, codes (Swedish only)


Born 1826-1958 Birth - Birth weight and risk of adult disease in offspring: etiologic determinants

BIRTH area of study, variables, codes

Born 1959-1985 STAGE - Swedish Twin Studies of adults: Genes och Environment

STAGE Area of study, variables, codes

Born 1959-1985 STAGE ONE - Swedish Twin Studies of adults: Genes och Environment

STAGE ONE area of study, variables, codes

Born 1992-1999 CATSS - The Child and Adolescent Twin Study in Sweden

CATSS Telephone interview (2007-) (Swedish Only)

CATSS Telephone interview (2007-) (Swedish Only)

CATSS Area of study, variables, codes


FAQ for researchers

Use the STR metadata portal to search and find phenotypic data of interest. PDF versions of earlier surveys and questionnaires can be obtained on the homepage.

No, but you need to hand in a draft for an ethical application together with other requested documents. In this manner we can help with the description of data, information to participants and consent if needed. No data will be handed out before adequate ethical approval has been obtaine

Since we use “first come - first served” principle, it depends on the number and complexity of requests already in line. A common waiting time is a few months after approval.  

Patient register (in- and outpatient specialist care, until 2016), prescribed drug register (until 2017), medical birth register (until 2015), cause of death register (until 2017), cancer register (until 2015), dog ownership (until 2016), conscription register (male twins born 1936-1995).

This is uncertain since our latest request was rejected by the Board of Health and Welfare. 

Yes, given ethical approval and a separate application and approval from the Board of Health and Welfare.

Yes, given ethical approval and approval from the external data source

On Swedish Twin Registry: For researchers | Karolinska Institutet (ki.se) you can read about the application procedure and what documents to include. To find and select the variables of interest you can use the STR metadata portal to create and download your variable list. You submit the application in iLab (corefacilities.org), which is the platform for KI core facilities. The cost for a standard application is 5000 SEK (application fee) plus 20 000 SEK (administration of data withdrawal).

Yes, you may send in your request as a feasibility test in iLab (corefacilities.org). Ethical approval is not needed at this stage and the cost is on hourly basis (750 SEK/hour). We run feasibility tests regularly.

The usual cost for application and delivery of phenotypic data is 25 000 SEK. Genotypic data is accessible for an additional 50 000 SEK. More details and information regarding conditions for access to samples are provided in the Service catalogue and pricelist.

For data received 2023 or later: “We acknowledge The Swedish Twin Registry for access to data. The Swedish Twin Registry is managed by Karolinska Institutet and receives funding through the Swedish Research Council un-der the grant no 2021-00180.” For data received before 2023: “We acknowledge The Swedish Twin Registry for access to data. The Swedish Twin Registry is managed by Karolinska Institutet and receives funding through the Swedish Research Council under the grant no 2017-00641.”


Presentation of the Swedish Twin Registry (pdf, ppt)

Presentation of STR (pdf)

Presentation of STR (ppt)

Acknowledgement in publications using STR data

In each publication the STR should be acknowledged in the following way:

If you received data before 2023: “We acknowledge The Swedish Twin Registry for access to data. The Swedish Twin Registry is managed by Karolinska Institutet and receives funding through the Swedish Research Council under the grant no 2017-00641.”

If you received data 2023 or later: “We acknowledge The Swedish Twin Registry for access to data. The Swedish Twin Registry is managed by Karolinska Institutet and receives funding through the Swedish Research Council under the grant no 2021-00180.”

Publications based on the Swedish Twin Registry

List of publications (pdf, updated April 25, 2023)

National infrastructures

The Swedish Research Council also supports other national infrastructures with resources that may be of interest.

CORS (Comparative Research Center Sweden) www.cors.se

CORS is a national research infrastructure consortium that incorporates the largest, most influential and most widely used, international and national survey programs in Sweden.

These are the European Social Survey (ESS), European Values Study (EVS), International Social Survey Programme (ISSP), Survey of Health, Ageing and Retirement in Europe (SHARE) and the Swedish National Election Studies (SNES). The Swedish Citizen Panel (SCP) at the SOM Institute is also part of CORS. SCP is a research driven webpanel that offers ways of conducting various methodological experiments as well as following individuals or groups over time. The aim of CORS is to enable class-leading comparative survey research, and to contribute to improved policymaking and democratic debate in Sweden.



NEAR promotes and supports aging research by facilitating the use of longitudinal population-based data from various well-known Swedish cohort studies on aging and health. It is based on a collaboration among eight Swedish universities and includes 15 databases with individual assessments. Additionally, NEAR collaborates with other national infrastructures such as SIMPLER and CORS. NEAR’s mission is to enable high-quality aging research by providing big health data while maintaining the same quality and richness as in single population-based studies. NEAR also aims to increase national and international exchange and collaboration and enhance the quality and generalizability of aging research results. NEAR provides a broad range of biomedical, clinical, social, and psychological health data from around 90,000 older adults followed for 12 to 52 years.

REWHARD (Relations, Work and Health across the life-course ̶ A Research Data infrastructure) 


REWHARD comprises the nodes LNU, SLOSH, IMAS and STODS. We work to strengthen the conditions for research on working and living conditions, sickness absence, health and well-being. REWHARD offers various services such as data access or analyses, sharing of statistical syntax files and advice on ordering and handling data. We also organise seminars on the use of Swedish databases for research within our field. REWHARD's nodes include longitudinal linked microdata covering several decades from both surveys and nationwide registers for tens of thousands to several million individuals.



SIMPLER consists of two large population-based longitudinal cohorts and three region-specific sub-cohorts, an extensive biobank with blood, urine, fat biopsies, saliva, stool, and DNA, and a large database that now includes a growing component of omics. This national infrastructure, initiated in 1987, provides information about 110,000 men and women from three regions. Over the years, the participants have undergone repeated examinations, and the SIMPLER database has been updated against national registries. The infrastructure's primary purpose is to provide users with integrated longitudinal lifestyle data, register information, and molecular measurements to foster high-quality research regarding the genetic and lifestyle causes of the development and consequences of late-onset disorders.

SwedPop: Svenska befolkningsdatabaser för forskning 


SwedPop is a national research infrastructure with harmonized individual-level, life-course, cross-sectional and panel data, including large populations and a variety of social and geographical settings over long time periods. Data in SwedPop includes numerous demographic and socio-economic variables and covers large parts of the Swedish 19th and 20th century population, including the largest cities Stockholm and Gothenburg. Fully developed the infrastructure will offer access to linked life-course data for c. 3.5 million individuals from the 17th to the 20th centuries in selected regions, full-count national censuses 1880-1950 and death records from 1860-2019. The coordination in SwedPop improves the quality and comparability of the data, increases the spatial coverage, and bridges the gap between historical and modern population registers.

UGU (Utvärdering Genom Uppföljning)


Evaluation Through Follow-up (UGU) is a longitudinal study that has developed a unique database within the field of educational science. UGU consists of several longitudinal surveys that have been combined into a whole, which together creates a cohort sequential database. The database contains 10 different birth cohorts that are nationally representative samples which make it possible to carry out longitudinal, sequential, and cross-sectional analyses. The data consists of administrative tasks, measures of study prerequisites, survey tasks, study results and cognitive tests. UGU is one of the oldest social science databases in Sweden, the first survey was carried out in 1961.

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