By Dina Martin
Along with her mother, who is a retired teacher, Modoc Teachers Association member Patti Perkins Carpenter has been a participant in the California Teachers Study, a longitudinal study that has tracked cancer and the health of more than 133,000 female teachers.
Little did she know when she became a participant that she would be battling cancer herself in the ensuing years.
She remembers going through the extensive health survey and being amused by questions that asked her how often she eats broccoli or whether she lived near high tension wires or grew up around feedlots. The survey is part of a research project of the Northern California Cancer Center (NCCC), which studies cancer causes, trends and prevention. The center has been collaborating with several California institutions in collecting and analyzing survey data and data on cancer occurrence for the study.
"As I filled it in, I thought how fortunate I was that no one in my family had cancer. I thought I was healthy and that I ate right," says Carpenter. "It just shows you that you never know what's going to happen."
Carpenter, like thousands of other teacher participants, has provided valuable information that is leading to some interesting cancer theories and is likely to be used in research well into the future.
Begun in 1995, the initial study collected data from an extensive questionnaire that focused on lifestyle, medical history, and women's health. Since then, study participants have completed additional surveys. Questionnaires were mailed to every CalSTRS member, which resulted in over 40 percent of the members wanting to be involved in the study. The questionnaire information has been linked with data from the California Cancer Registry, which has tracked all cases of cancer diagnosed in the state since 1988.
"Teachers have been so valuable to us in this study," says Pamela Horn-Ross, a research scientist for the NCCC and a founding investigator of the California Teachers Study. "They've been totally cooperative, enthusiastic and engaged."
"They've given us great data. In some ways, California teachers will be the ‘Harvard Nurses' of the future," says NCCC research scientist Christina Clarke, referring to a landmark study of more than 180,000 nurses that provided a wealth of information about women's health. "In fact, we are now planning a new study involving California teachers that we hope will be as impactful as the nurses' study in providing important new data to inform women about how dealing with menopause will affect their risk of cancer and heart disease in the future."
Early findings from the study confirmed concerns previously expressed by teachers that they experienced a higher rate of breast cancer than comparable women in California.
The study has found that teachers have much lower rates of lung cancer and death from heart disease than the general population because they are a "spectacularly non-smoking group," according to Clarke.
Unfortunately, research also indicates that teachers have a 30 percent higher rate of uterine cancer and a 50 percent higher rate of melanoma (see story, Melanoma: Know the risks), two areas the study's investigators are now actively researching.
Scientists don't yet know why the breast cancer rate is still higher among teachers. One theory is that it may have something to do with teachers' reproductive patterns. Teachers in the study tended to delay childbirth, or did not have any children altogether, both of which have been associated with a higher risk of breast cancer.
Some of the survey information is leading Clarke to some brand-new ideas that may be important in the prevention of breast cancer. For example, data from the survey shows that teachers who grew up among stables, farm animals, and their manure have a lower incidence of breast cancer than the rest of the female population.
Clarke is conducting a study that tests the "hygiene hypothesis" as it relates to breast cancer. This idea holds that reduced or delayed exposures to microbes in childhood, or living in a mostly disease-free, sanitized environment, hampers development of a healthy immune system.
In her grant application, Clarke wrote, "Some of the impetus for this research comes from hearing breast cancer survivors say, ‘I've never been sick a day in my life, and now I get breast cancer!'"
Working in collaboration with the Northern California Cancer Center are several other institutions, including the University of California at Irvine, the University of Southern California, and the City of Hope, all of which are conducting research studies that draw from the teacher data. Researchers from NCCC and their partner institutions are looking at other factors that may have an impact on cancer, including obesity, diet, alcohol, second-hand smoke, and air pollution.
"I am so proud of our teachers," says CTA President David A. Sanchez. "Their participation in this important study shows that their influence goes far beyond the classroom. The information that thousands of our teachers have provided will one day have a major impact on the health of women in this nation and the world."
For more information on this study, visit www.calteachersstudy.org; for prevention tips visit www.nccc.org/preventiontips.
Interested in participating in future cancer research? California teachers are needed to volunteer for new studies. For more information, go to www.teachersresearch.org.