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Filling out a survey

How did the California Teachers Study begin?

In 1995, using cigarette sales tax revenue set aside for breast cancer research, the State of California provided one-time funding for an epidemiologic study designed to understand why female teachers had higher rates of breast and other cancers. The CTS officially began in 1995-1996, when 133,477 female active or retired public school professionals (primarily teachers or administrators) completed and returned a mailed, self-administered questionnaire. 


Why teachers?

Research has long shown that teachers may be at higher risk of breast cancer. In 1987, the California Department of Health services noted high levels of breast cancer diagnoses among California teachers, although the rate of death from breast cancer remained low. The California Teachers Study was founded to study this excess risk and to examine the causes of breast and other cancers among teachers in California.

What is a cohort study?

Cohort studies are designed to investigate the relationship between risk factors and health outcomes. In a prospective cohort study like the CTS, cohort participants are followed over time to track the development of diseases and other health outcomes.


The California Teachers Study is a closed cohort study, which means that all study participants were enrolled at one time (in 1995) and additional participants will not be enrolled for the duration of the study.

What is epidemiology?

Epidemiology is the study of how disease spreads and can be controlled. Epidemiology examines how and where disease occurs among populations.

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