Tens of thousands of Bay Area women and girls are participating in studies to find out why unusually high breast cancer rates appear in large swaths of the Bay Area.

Here are details on some of the major studies under way:

The Child Health and Development Studies

  • Began nearly 50 years ago with 15,000 women in the Kaiser Foundation Health Plan who were pregnant between 1959 and 1967. Now includes the second and third generation of their families. Participants asked about their health, lifestyle and experiences that could influence their pregnancies. Researchers take blood samples to check for exposure to chemicals.

  • One goal is to learn whether there is a link between a mother's environmental exposures and her daughter's risk of developing breast cancer.

  • First study to link the pesticide DDT to breast cancer and show that girls are particularly vulnerable to exposure before puberty.

  • Also first study to link exposure to DDT and PCBs in the womb with reproductive problems in women.

  • Originally a joint project of UC Berkeley and Kaiser Permanente, now overseen by the Public Health Institute in Oakland.

  • Funded by the National Institutes of Health and the California Breast Cancer Research Program.

  • Information at http://chdstudies.org/3gs and http://chdstudies.org.

    Breast Cancer and the Environment Research Program

  • A puberty study involving 1,200 girls ages 7 to 8 in western Contra Costa, Alameda, Marin and San Francisco counties, as well as in Cincinnati and New York.

  • Researchers take blood and urine samples annually to check for environmental exposures. They also track diet, physical activity, smoking and the onset of puberty and menstrual periods.

  • One goal is to find out what may be leading to early onset of puberty, which has been linked to an increased risk of breast cancer.

  • Funded by the National Institute of Environmental Health Sciences and the National Cancer Institute.

  • Information at www.bcerc.org.

    The California Teachers Study

  • This statewide study, set up in 1995, involves 133,400 current and former public school teachers and administrators in the California State Teachers Retirement System.

  • Participants answer questions about everything from diet and exercise to their medications, hormone therapies and environmental exposures.

  • Study has found higher-than-expected rates of breast cancer among teachers compared with statewide averages.

  • Funders include the state of California, National Cancer Institute, California Breast Cancer Research Program, California Tobacco Related Disease Research Program, National Institute of Environmental Health Sciences and Department of Defense Breast Cancer Research Program.

  • Information at www.calteachersstudy.org.

    Immigrant Experience and Breast Cancer Risk in Asians

  • This study will explore what may be causing differences in breast cancer rates among subgroups of the Asian-American population, including immigrants and those born in the United States.

  • Looking at diet and weight gain, family and community influences, social stresses and other factors.

  • Overseen by the Fremont-based Cancer Prevention Institute of California.

  • Funded by the California Breast Cancer Research Program.

  • Information at http://cbcrp.org.127.seekdotnet.com/research/PageGrant.asp?grant_id=13074.