STR – Swedish Twin Register

The Twin Register is a population- and individual-based database of twins, which forms an infrastructure for research, primarily within medical epidemiology. The register is relevant within many other fields of research as well, such as pharmacology, genetics, clinical medicine and psychiatry, and within sociology, economics and political sciences.

The Twin Register has existed since 1959, and covers information about approximately 200 000 twins born after 1886 from all over Sweden. Twins are invited continually to be part of the register when they turn 9 years old. For a large proportion of the twins, in addition to information on zygosity, surveys and linked register data, there is also data from clinical examinations and sample collections with DNA and serum.

The Twin Register enables research into areas such as heredity or investigations of familiar factors in studies of the causes of disease and behaviour, as well as research into the consequences of being born a twin, which often entails factors such as low birth weight.

The consortium operating the Swedish Twin Register is coordinated by Karolinska Institutet, with participation from a number of other higher education institutions.