California Twin Program (CTP)
The CTP is a population-based registry of over 50,000 twins born between 1908 and 1982 in the state of California in the United States of America. Eligible twins were identified from California birth records, contact addresses obtained from government vehicle records, and letter invitations sent out between 1991 and 2000 across four waves of recruitment. Participants represented individuals from 25,725 same-sex and 11,240 opposite-sex twin pairs.
Study design
Registry, Cohort - twin
Number of participants at first data collection
51,069 (participants)
Age at first data collection
Varied (participants)
Participant year of birth
1908 - 1982 (participants)
Participant sex
All
Representative sample at baseline?
The original twin cohort was representative of the 1990 California born population.
Sample features
Country
Year of first data collection
1991
Primary Institutions
University of Southern California (USC)
Profile paper DOI
Funders
Leukemia & Lymphoma Society (LLS)
National Institutes of Health (NIH)
Ongoing?
Yes
Data types collected
- Interview – phone
- Secondary data
- Self-report questionnaire – paper or computer assisted
- None
- None
- Healthcare data
- Medical birth registry
- Mortality data
- Other government data
Engagement
Keywords
Consortia and dataset groups
