Study of Dementia in Swedish Twins, 1990-1999 (ICPSR 25963)

Published: Jun 4, 2010

Principal Investigator(s):
Margaret Gatz, University of Southern California, and Karolinska Institutet (Stockholm); Nancy Pedersen, Karolinska Institutet (Stockholm)

Version V2

The Study of Dementia in Swedish Twins was designed to study the relative influence of genetic and environmental factors for Alzheimer's disease and other types of dementia and to test the role of specific environmental exposures that might constitute risk or protective factors for dementia. The first seven years of the Study of Dementia in Swedish Twins was based on the population from the SWEDISH ADOPTION/TWIN STUDY OF AGING (SATSA), 1984, 1987, 1990, and 1993 (ICPSR 3843). SATSA consists of a subset of 3,838 same-sex twins from the population-based Swedish Twin Registry; however, the baseline sample for the Study of Dementia in Swedish Twins consists of 2,394 individuals who were alive and born in 1935 or earlier. The Study of Dementia in Swedish Twins data cover background information (sex, zygosity, rearing status, ages at each data collection point, age at death), cognitive screening (which took place in conjunction with each SATSA wave of data collection), clinical dementia diagnoses for those who received a complete dementia workup (both baseline and longitudinal), cognitive test results (both baseline and longitudinal), medical history and medical risk factors (medical examination; blood pressure; laboratory results; history of neurologic, coronary, mental, and other diseases; smell test; history of head injury, anaesthesia, fevers, medications, dietary history with respect to fish, raw meat, and acidic foods prepared in aluminum pans), residential, occupational, and leisure activities history (including exposure related to welding, hairdressing, agriculture, medical settings, painting and other sources of organic solvents, crystal, carbon monoxide, radiation, raw meat and game; participation in contact sports; antiperspirant containing aluminum; history of smoking; history of use of alcohol), family history of dementia, and APOE genotype. SATSA is archived separately at ICPSR, see ICPSR 3843. The SATSA and the Study of Dementia in Swedish Twins files contain a common ID number that can be used to create a crosswalk between the files.

United States Department of Health and Human Services. National Institutes of Health. National Institute on Aging (R01 AG08724)

Swedish Research Council

Users interested in obtaining these data from NACDA must request and complete the Study of Dementia in Swedish Twins, 1990-1999, Restricted Data Use Agreement form. Users can download this form from the download page associated with this dataset. Completed forms with original signature(s) should be emailed to

Inter-university Consortium for Political and Social Research

1990-05 -- 1999-03

1990-05-21 -- 1999-03-07

Selected documentation and the Data Use Agreement are available for download from the ICPSR website; however, the data and other selected documentation are restricted from public release and will be distributed only upon completion and receipt of the Data Use Agreement

The Study of Dementia in Swedish Twins population is derived from the SATSA study. SATSA consists of a subset of 3,838 same-sex twins from the population-based Swedish Twin Registry, specifically, all pairs from the twin registry who indicated having been reared apart, and a matched sample of pairs who were reared together, drawn from the twin registry to correspond in sex, year of birth, and county of birth to the reared apart twins. At baseline in 1984, 2,845 of these individuals were alive (1,223 pairs and 399 singletons), defining the SATSA population. Dementia-related data collection by the Study of Dementia in Swedish Twins entailed the following sample: Individuals were included if they were alive in 1987 and if they were in the SATSA sample as originally drawn, whether or not they had ever responded to any SATSA data collection effort, and whether or not their twin sibling was alive. Due to the low prevalence of dementia in middle age, only individuals born in 1935 or earlier were included in the dementia study. The resulting base sample for the Study of Dementia in Swedish Twins consisted of 2,394 individuals.

All pairs of same-sex twins from the Swedish Adoption/Twin Study of Aging sample from the Swedish Twin Registry born in 1935 and earlier.

clinical data

survey data

record abstracts

cognitive assessment test

face-to-face interview

mail questionnaire

paper and pencil interview (PAPI)

on-site questionnaire

80.1 percent

DSM-III-R CDR MMSE CES-D Short Portable Mental Status Questionniare Swedish Naming Verbal Comprehension Swedish WAIS Information Test Figure Copying Clock Test Digit Span Logical Memory CERAD Word List Symbol Digit MIR/Apartment test Koh's Block Design test Verbal Fluency Figure Logic Figure Identification Synonyms Thurstone Picture Memory



2010-06-04 Documentation files have been updated.

2010-05-06 ICPSR data undergo a confidentiality review and are altered when necessary to limit the risk of disclosure. ICPSR also routinely creates ready-to-go data files along with setups in the major statistical software formats as well as standard codebooks to accompany the data. In addition to these procedures, ICPSR performed the following processing steps for this data collection:

  • Created variable labels and/or value labels.


  • The public-use data files in this collection are available for access by the general public. Access does not require affiliation with an ICPSR member institution.

  • One or more files in this data collection have special restrictions. Restricted data files are not available for direct download from the website; click on the Restricted Data button to learn more.

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This study is maintained and distributed by the National Archive of Computerized Data on Aging (NACDA), the aging program within ICPSR. NACDA is sponsored by the National Institute on Aging (NIA) at the National Institutes of Heath (NIH).