The SALT study was initiated in 1998, with the purpose of screening all twins in Sweden born before 1958 for most common complex diseases, regardless of the status of their twin partner. The extensive interview included questions about illnesses and health, medication use, occupation, education, and lifestyle factors.

General Design

Study Design Cohort
Recruitment Target
  • Families
Number of Participants


Number of Participants with Biological Samples


Supplementary Information

Magnusson PK, Almqvist C, Rahman I, et al. The Swedish Twin Registry: Establishment of a Biobank and Other Recent Developments. Twin Res Hum Genet 2012; 16: 317-29. Pubmed ID 23137839.


Not Applicable
Don't Know
Possible Access to Data

Possible Access to Biosamples


The SALT study as well as SALTY and Twin-Gene projects are part of the Swedish Twin Registry (STR). More information on studies within the registry and the data collected could be found at :

Marker Paper

Lichtenstein P, Sullivan PF, Cnattingius S, et al. The Swedish Twin Registry in the third millennium: an update. Twin Res Hum Genet 2006; 9: 875-82.

PUBMED 17254424

Supplementary Information

The Swedish Twin Registry (STR) includes more than 190,000 twins - in principle all twins born in Sweden since 1886. The STR is made of three cohorts, each of which differs in method of ascertainment and extent of data collected: old cohort (born between 1886-1925), middle cohort (born between 1926-1958), and young cohort (born between 1959-1990). Same-sex twins from the old cohort were sent questionnaires in 1961, 1963, 1967, and 1970, and those from the middle cohort were sent a questionnaire in 1973.

SALT is a sub-study of the STR and it is a complete screening of all twins from this registry, regardless of gender composition or vital status of the pair and stems from the old and middle cohorts. In addition to the SALT interview, there was the TwinGene (2004-2008), SALTY (2009-2010) which included questionnaires and biosamples, and HARMONY (1998-2003) which included cognitive functioning screenings for those 65 and above, which have been conducted.

Study Timeline

Each colour in the timeline graph below represents a separate Study Population, while each segment in the graph represents a separate Data Collection Event. Clicking on a segment gives more detailed information on a Data Collection Event.


SALT population

The population consisted of twin pairs born in 1958 or earlier regardless of gender composition or vital status of the pair, selected from the Swedish Twin Registry and asked to participate to the study.

Sources of Recruitment

Specific Population
  • Other specific population : Swedish Twin Registry

Selection Criteria

Age Minimum age 40
Country Sweden

Sample Size

Number of Participants


Number of Participants with Biological Samples


Supplementary Information about Number of Participants

HARMONY: 14 164

TwinGene: 12 614 participants

SALTY: 11 372 participants

Data Collection Events

SALT - CATI interview

Computer assisted telephone interview collected...


SALT participants aged 65 or older were...

SALT - TwinGene

The primary aim to the TwinGene project was to...


The SALTY project focused on the younger part...


Variables classifications