Marin Breast Cancer Watch Publishes First Research Study

Group Announces Plans to Create Adolescent Education Program

(San Rafael, Calif., May 5, 2023) - Marin Breast Cancer Watch, a non-profit grassroots organization, announced today the results from its first research project, the Adolescent Risk Factors Study (ARFS), have been published in the scientific journal Breast Cancer Research. The study can be found online at:

Completion of the study marks the conclusion of the first community-based research study in the Bay Area to look at breast cancer.

"This is an important step forward because it shows that the community can not only be a part of the research process, but be part of helping find the causes of breast cancer," said Janice Barlow, executive director of Marin Breast Cancer Watch. "Publication of this study is just one more piece of the puzzle as we try to understand what is causing breast cancer."

In 1997, members of Marin Breast Cancer Watch sought help from researchers and scientists to help them better understand the causes of breast cancer in Marin. Dr. Margaret Wrensch, PhD, a Professor of Epidemiology and Biostatistics at the University of California, San Francisco, answered the call and helped the community organization devise the Adolescent Risk Factors Study. At the time, there was very little research into how the experiences of adolescents might affect their chances of getting breast cancer later in life.

The Adolescent Risk Factors Study was designed to understand if adolescent and pre-adolescent exposures and experiences differ between women with and without breast cancer in Marin County.

Trained interviewers individually interviewed approximately 300 Marin County women diagnosed between July 1, 2023 and June 30, 2023 with breast cancer (cases), and 300 Marin County women without breast cancer (controls), matched for age and ethnicity.

Results of the study found striking similarities between the cases and controls as well as several differences that were significant. Lifetime number of years lived in Marin was 24.2 years for both groups and the mean age first lived in Marin was 28.8 for controls and 29.6 for cases. Other factors that were not significantly different between cases and controls included: having a first degree relative with breast cancer (20% of controls and 18 % of cases); history of non-cancerous breast biopsy; current socioeconomic status; age of first period; age at first birth or pregnancy (mean of 25.1 for controls and 25.3 for cases); use of hormone replacement therapy; height; health insurance status; and frequency of pelvic exams and pap tests.

Significant differences were noted in other factors. Cases were more likely than controls to report: a high socioeconomic status before the age of 21; four or more mammograms in 1990-1994; giving birth without breast feeding; being premenopausal; never having used birth control pills; having a lower highest body mass index; beginning drinking after age 21; drinking on average two or more drinks per day; and being raised in an organized religion.

The similarities between cases and controls in this study, and the high incidence of some breast cancer risk factors that were found in many areas, suggest that both groups are at high risk for breast cancer. Specific findings, in combination with the results of other recent prospective studies, suggest that decreased alcohol consumption and increased breastfeeding after childbirth, modifiable risk factors in adults, might help to reduce breast cancer risk.

"This research project was initiated due to community concerns." Barlow continued. "Early in the process, meetings composed of community members were held to help focus research direction and techniques. At every step in the process, MBCW research members have played an active role."

The principal investigators on the study were Margaret Wrensch, Ph.D, and Georgianna Farren, MD, representing Marin Breast Cancer Watch.

The focus on community-based research as a model has established Marin Breast Cancer Watch as a leading advocate for community concerns and ideas in research projects.

In continuing its leadership role in Marin, Marin Breast Cancer Watch also announced the creation of a new education outreach program aimed at adolescent girls, the "Adolescent Breast Cancer Education and Prevention Program."

The new initiative will take the information learned from the Adolescent Risk Factors Study, and results from other adolescent breast cancer studies, and create an education program that gives young girls the information and tools they need to make informed decisions about their health.

Barlow said the program is currently being developed and interested members of the community are welcome to participate in the process. The first step in creating the program is to conduct a community wide assessment about the current state of health education in Marin County regarding health risk, adolescent health and breast cancer. Then the group will host a series of focus groups with young girls and mothers to learn where breast cancer fits into the agenda of teenage girls in Marin. Finally, an evaluation of other programs around the country will be made to help determine tools and information that may be helpful in Marin.

"The idea for this program came from discussions with women in the community who want to make sure their daughters have information about breast cancer and health," Barlow said. "There is a real need to not only inform, but to work with young people to better understand their concerns and ideas."

Working with health care professionals, educators, young girls and others from the community, Marin Breast Cancer Watch hopes to create a pilot program that can be a model for other communities.

Marin Breast Cancer Watch is a grassroots, non-profit organization dedicated to finding the causes and stopping the epidemic of breast cancer. The organization accomplishes its mission through community-based participatory research, education and public policy advocacy with a focus on creating a healthy environment.

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