I C P S R

National Institute on Aging

Description & Citation--Study No. 21041

Bibliographic Description

Study No.:

21041

Title:

Longitudinal Study of Aging Danish Twins, 1995

Principal Investigator(s):

Christensen, Kaare, University of Southern Denmark. Institute of Public Health

Vaupel, James W., Duke University

Funding:

United States Department of Health and Human Services. National Institutes of Health. National Institute on Aging (Grant # P01AG08761)

University of Southern Denmark

Bibliographic Citation:

Christensen, Kaare, and James W. Vaupel. Longitudinal Study of Aging Danish Twins, 1995. ICPSR21041-v1. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2009-06-09. doi:10.3886/ICPSR21041.v1

Scope of Study

Summary:

The focus of the "Longitudinal Study of Aging Danish Twins (LSADT)" has been on elucidating the causes of variation in survival, health, diseases, loss of abilities, and cognitive functions among the elderly and oldest-old. The LSADT was conducted every two years between 1995 and 2005 and consists of six waves. The study comprises interviews of elderly Danish twins aged 75 years and older (later 70 years and older). At each interview wave, the interview assessment has been based on the interview used in the previous waves, which covers health, physical functioning, cognitive functioning, depression symptomatology, social factors, lifestyle characteristics, and quality of life. The self-report interview assessments have been supplemented with objective indicators of physical strength and agility, behavioral speed, and pulmonary peak-flow. Biological material was also collected from the participants for future DNA analysis.

Subject Terms:

activities of daily living, aging, assisted living, assistive devices, cognitive devices, cognitive functioning, disease, health status, home care, mental health, older adults, physical fitness, physical limitations

Geographic Coverage:

Denmark, Global

Time Period:
  • 1995  (February-April)

Date of Collection:
  • 1995  (February-April)

Universe:

All twins aged 75 years and older born in Denmark and still residing in Denmark, not including the Faroe Islands and Greenland.

Data Types:

survey data

Methodology

Sample:

The LSADT used a cohort sequential design. The sampling for all waves of LSADT is described in M. McGue and K. Christensen. "Social Activity and Healthy Aging: A Study of Aging Danish Twins." Twin Research and Human Genetics 10,2 (2007), 255-266.

Weight:

No weights have been used

Mode of Data Collection:

computer-assisted telephone interview (CATI), face-to-face interview

Response Rates:

Physical functioning: The self-reported assessment of physical functioning is based on an instrument that was developed and previously validated in Denmark (Avlund et al, 1995). It has been used essentially unchanged throughout all waves of LSADT.

Cognitive functioning: The cognitive battery includes the Mini Mental State Examination (MMSE, Folstein et al, 1995) and five brief cognitive tests selected to be sensitive to age-related changes (McGue and Christensen, 2002).

Depression symptomatology: The assessment is based on an adaptation of the depression section of the Cambridge Mental Disorders of the Elderly Examination (CAMDEX, Roth et al, 1986; Johnson et al, 2002).

Social activity: The Social Activity scale was not administered in LSADT until 1997.

Extent of Processing:

All archived data undergo a confidentiality review and are altered when necessary to limit the risk of disclosure. The archive 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, the archive performed the following processing steps for this data collection:

  • Performed consistency checks.
  • Standardized missing values.
  • Checked for undocumented or out-of-range codes.

Access and Availability

Note:

Detailed file-level information (such as record length, case count, and variable count) is listed in the file manifest.

Original ICPSR Release:

2009-06-04

Restrictions:

The data are restricted from general dissemination. Users interested in obtaining these data must complete a Restricted Data Use Agreement form and specify the reasons for the request. A copy of the Restricted Data Use Agreement form can be requested by calling 800-999-0960. Researchers can also download this form as a Portable Document Format (PDF) file from the download page associated with this dataset. Completed forms should be returned to: National Archive of Computerized Data on Aging (NACDA), Inter-university Consortium for Political and Social Research, Institute for Social Research, 330 Packard, Ann Arbor, MI 48104, or by fax: 734-647-8200.