California Teachers Study (CTS): Whole Genome Sequences From Under-Represented Populations

The California Teachers Study (CTS) is a prospective observational cohort of N=133,477 adult women who have been followed since 1995. Participants completed up to six surveys and have been linked with cancer, hospitalization, and mortality data. In 2013-2016, over 14,000 CTS participants donated blood samples for future research. For this project, DNA was extracted in 2023 from 1694 buffy coats and 56 blood clots from N=1750 CTS participants whose self-reported race/ethnicity was Asian (398), Asian or Pacific Islander (18), Black or African American (189), Native American (128), Native Hawaiian or Other Pacific Islander (66), White Hispanic (719), or more than one race (232). Whole genome sequencing (WGS) was performed at CIDR in 2023-2024. WGS data and accompanying phenotype data are available through dbGaP. In addition, all CTS data are available to the research community via the CTS Researcher Platform (www.calteachersstudy.org), a secure cloud-based environment that includes data, software, documentation, and collaboration workspaces. ]]>
When the CTS began in 1995, participants had to be adult females who were active or recently retired members of the California State Teachers' Retirement System (CalSTRS). The CalSTRS provided the source population from which the CTS cohort was drawn. The CTS biobanking projects had additional inclusion/exclusion criteria. Participants had to live in California, be under age 80 years, and consent to have their biospecimen used for future research. A total of 56 biospecimens of the N=1750 were obtained during a 2015-2019 nested case-control study of breast cancer; for this project participants had to either have been diagnosed with breast cancer before age 80 or have no personal history of cancer. ]]>
The CTS is approaching its 30th year of continuous follow-up and ongoing high-quality research. Although its original focus was female breast cancer, the study has always collected diverse exposure and phenotype data that can support wide-ranging research on other cancers, clinical conditions, and aspects of women's health. Six study-wide surveys collected data on reproductive history, diet, physical activity, family history, personal health, medication use, social support, and other lifestyle exposures. Annual linkages have provided detailed and individual-level data on cancers diagnosed and inpatient hospitalizations (plus emergency department and ambulatory surgery visits) during follow-up. Extensive geospatial-based and environmental exposure data have been added. The CTS is also one of the first NCI-funded observational cohort studies to adopt a data-commons approach and make its all data and resources available to the research community via a secure cloud environment. The CTS Researcher Platform, available at the “For Researchers” tab on the CTS website, offers data, documentation, interactive data visualizations, software, and collaboration workspaces for exploring CTS data or conducting hypothesis-driven research. ]]>