SALT - Screening Across the Lifespan Twin Study
The SALT study was initiated in 1998 and is a sub-study of the Swedish Twin Registry (STR) where a complete screening of all twins born 1958 or earlier were included (n=44 919). There are three sub-studies of the SALT study; 1) HARMONY (1998-2003), where SALT participants who were 65 years or above were screened for dementia. All twins who screened positive together with their co-twins, as well as cognitively intact controls went through a clinical examination (n=1 557); 2) TwinGene (2004-2008) where biological samples were collected from a subset of the SALT population (n=12 614); 3) SALTY (2009-2010), which included another subset of twins from the SALT study who were born between 1943 and 1958 (n=11 372). Data have been collected at three waves over a total of ten years for the older cohort (included in HARMONY) and 12 years for the younger cohort (included in SALTY). The purpose of the SALT study was to screen all twins in Sweden born 1958 or earlier for the most common complex diseases, regardless of the status of their twin partner. • In the SALT study, computer assisted telephone interviews collected information on twin and family status, height, weight, education, occupation, use of alcohol, tobacco, and caffeine, common illnesses, medications, and gender- and age-specific questions. Information about maternal and birth characteristics were also retrieved from the participants' birth records. • In HARMONY, a cognitive screening was based on the twin’s performance on the TELE cognitive screening instrument, which incorporates the ten-item mental status questionnaire (MSQ), two other cognitive domains, and questions about health and daily functioning. For individuals who performed poorly on the TELE, an informant was interviewed with the Blessed Dementia Rating Scale (BDRS), with questions about how much the twin’s cognitive status interfered with their daily functioning. • HARMONY twins suspected of dementia, their co-twins, and a control sample were referred for a clinical workup. This included a complete medical history, including use of prescription and non-prescription medications, as well as the onset and sequence of memory and cognitive symptoms, collected through medical records review and interviews with the participant and an informant. Participants also underwent an assessment conducted by a nurse and a physician, which included a physical and neurological examination, a neuropsychological assessment, and referral for neuroimaging. Dementia diagnosis, including differential diagnosis, was then set at a multidisciplinary conference. • The primary aim of the TwinGene project was to enhance the SALT study with biological specimens. Participants were asked to fill out a questionnaire about common diseases and to contact their local healthcare facility for health checkup and blood sample collection. • In the SALTY project, data collection consisted of an extensive self-reported paper-questionnaire and an internet-based investigation that included questionnaires on musical experience, tendency to experience psychological flow and creative achievement, as well as tests of cognitive and motor performance. In addition, saliva was collected for DNA extraction. 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. For more detailed information https://neardb.near-aging.se/search#lists?type=variables&query=study(in(Mica_study.id,salt)),variable(limit(0,20))
Zagai, U., Lichtenstein, P., Pedersen, N., & Magnusson, P. (2019). The Swedish Twin Registry: Content and Management as a Research Infrastructure. Twin Research and Human Genetics, 22(6), 672-680. doi:10.1017/thg.2019.99
The Swedish Twin Registry (STR) is a national research register open to academic and industrial users. The mission of the STR is to provide a longitudinal research resource for epidemiological and molecular studies of twins. It was originally established in 1959 with particular focus on cardiovascular disease and cancer. Since then, interest has expanded to almost all common diseases and health problems. The STR has contacted all living Swedish born twins (over 9 years) and is the world´s largest twin registry. The current system of twin ascertainment, which has been running in perpetual mode for 13 years, is done through parental interviews when the twins turn 9 years of age. Nationwide questionnaires and telephone interviews have been conducted for different birth cohorts since the beginning of the 1960s. Longitudinal information about health and disease is obtained through regular linkages to the Swedish health registries. DNA from 55 000 twins and serum of 13 000 twins are stored at KI Biobank and is subject to use to new investigations and analyses. Genome-wide genotyping of more than 30 000 participants has been completed and genotypes can be used for co-analysis for different outcomes and characteristics. We apply for funds to keep up the register, continue the ascertainment of 9-year old twins and introduce, in parallel, a nation-wide system for ascertainment of new-born twins with concomitant sampling of umbilical cord blood and immediate zygosity testing.
We apply for a continuation of the support of the Swedish Twin Registry (STR), a research infrastructure for population based, epidemiological and molecular studies of twins. The purpose of the STR is to enable research about the importance of genetic and environmental factors for health, lifestyle and behavior.The STR facilitates access to data, samples and twin-contacts for de novo data-collection. For more than 60 years, it has been used for research on a large number of diseases, behaviors and health problems. All living Swedish born twins over the age of 9 years have been contacted by the STR and it is thereby the largest twin registry in the world.Nationwide questionnaires, measurements and telephone interviews have been conducted for different birth cohorts since the 1960s. Broad consents and a unified system make it possible to combine data and samples over the sub-studies to address new research questions. Beside self-reported health and exposures, additional critical information is obtained through regular linkages to the national health registers. At present, the STR holds DNA and other biological samples from more than 58 000 twins to be used for new analyses. Genome-wide genotyping is available for the vast majority.The STR is managed by Karolinska Institutet and led by a Steering Group with mandate for periods of 3 years. There is also an advisory National Council with members from several universities that meets two times per year. It provides an academic arena for input and communication regarding strategies impacting the research enabled by the STR in the future. The grant will support the running costs of the new twin contacts, sample and data collections, upholding the secure database and provide access to data for researchers. The national added value consists in the opportunity to manage and develop an already productive infrastructure in directions that benefits a national range of researchers in a cross disciplinary and transparent manner.
Public Health, Global Health and Social Medicine
Geographical distribution of dominance of pathologies (allergies, cancers, respiratory diseases, etc.), information indicating the effect on health (biomarkers, decline of fertility, epidemics) or well-being of humans (fatigue, stress, etc.) linked directly (air pollution, chemicals, depletion of the ozone layer, noise, etc.) or indirectly (food, genetically modified organisms, etc.) to the quality of the environment.
near- national e-infrastructure for aging research