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The CTS at 25

The first CTS questionnaire was mailed to participants back in 1995, when a gallon of gas cost $1.15, had just sold its first book, and the world population was 5.7 billion. Since we first began this study, a lot has changed!

As we ring in 25 years, we want to commemorate how much we have accomplished together. Over the next few blog posts, we’ll be celebrating the researchers, data, technology, and study participants that have made this tremendous work possible for two and a half decades.

Where We Began

In the late 1980's and early 1990's, the California Department of Public Health noted high rates of breast cancer diagnosed among women who worked in California schools. Using funds from cigarette sales tax revenue set aside for breast cancer research, the California Teachers Study was founded to study this risk.

In late 1995 and early 1996, 133,477 participants completed Questionnaire 1. That 16-page paper questionnaire laid the foundation for what would become the California Teachers Study.

In the years that have followed, the CTS has collected survey data and multiple biospecimens from study participants, maintained linkages with the California Cancer Registry and the Office of Statewide Health Planning and Development, and combined those data to assess risk factors for breast and other cancers.

Where We are Now

Since you completed that first questionnaire, the California Teachers Study has:

  • Received more than 515,000 questionnaires from study participants, creating millions of data points for analysis

  • Collected more than 35,000 biospecimens for research

  • Identified nearly 40,000 different cancer diagnoses among study participants

  • Gathered data on more than 730,000 participant hospitalizations

Using this robust research resource over the past 25 years, researchers have generated important scientific contributions about risk factors for breast and other cancers, chronic health conditions, and how genetics, reproductive health, body size, diet, physical activity, and other factors contribute to health outcomes.

Today, there are more than 200 scientific publications using California Teachers Study data. Use the visualization to explore the science made possible by your participation!


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