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Last Edited: 5/11/2005

Environmental Tobacco Smoke Exposures in California Teachers Study Cohort
07/1998 - 11/2002

There is strong evidence that environmental tobacco smoke (ETS) poses a hazard to human health.  There remain, however, substantial and important gaps in our knowledge, particularly with respect to the prevalence and correlates of ETS exposures and the role of ETS in diseases other than lung cancer.  This study is designed to directly address these limitations in our knowledge.  Specifically, the study aims to:

  • Characterize both temporal and cohort-specific patterns of historical ETS exposures in the home, the workplace and in other settings.
  • Characterize the correlates of ETS exposures.
  • Conduct a preliminary short-term assessment of the associations between reported historical ETS exposures, active smoking and targeted health outcomes including cancer incidence and acute asthma episodes.
The study is based on data collected as part of the California Teachers Study (CTS) from a cohort of 133,479 female California professional school employees who completed detailed questionnaires concerning personal and family medical history, diet, physical exercise, environmental exposures, reproductive history, alcohol consumption, and active and passive smoking.  Health outcome data is derived from linkage of cohort to California's statewide cancer registry and hospital discharge data sets.  The health outcome of primary interest to this study is breast cancer.  To date, literature on the relationship between tobacco smoke and breast cancer is equivocal.  The California Teachers Study (CTS) offers a promising opportunity to evaluate this relationship.  In addition to information on lifetime active smoking history, the CTS has collected extensive information on ETS exposures. Many studies of ETS-related health risks, particularly those examining cancer outcomes, have relied on spousal smoking as an index of exposure and have been limited in their ability to adjust for other risk factors of interest.  Additionally, most ETS research has focused on exposures in the home as adults; very little is known about cancer risks associated with childhood ETS exposures.  The data collected from the CTS surveys offer extensive lifetime ETS exposure histories encompassing exposures in the home, at work and in other settings during childhood and each subsequent decade of life.  Information on dose and duration of exposure for each of these settings and time periods was collected as well.  This allows study the examination of risks associated with exposures at different ages and in all types of settings.

The unique detail for ETS historical exposures in this large and ethnically diverse cohort, together with rich covariate information and short-term prospective health outcome information for target diseases of special interest, provide an exciting opportunity to address many of the important data gaps in this area of inquiry.

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