Women's Health: Searching for Clues

"Can antiperspirants cause breast cancer?" a Green Guide reader asked recently, on the heels of an Internet rumor. Reassuringly, the first-ever study to investigate the issue, published in the October 16, 2002, Journal of the National Cancer Institute, found no difference in antiperspirant or deodorant use between 813 women with breast cancer and 793 without.

Here are some other recent looks at what environmental exposures may play a causative role in diseases.

Breast cancer

The Long Island Breast Cancer Study, published in August 2002, compared 1,508 women with breast cancer to 1,556 women without. Researchers concluded that some organochlorine chemicals, including the pesticides chlordane, dieldrin, DDT and its breakdown product DDE, as well as PCBs-all banned in the 1970s and '80s-did not increase the risk of breast cancer. However, Shanna H. Swan, Ph.D., professor of family and community medicine at the University of Missouri, Columbia, protested in a letter to The New York Times that "the Long Island Breast Cancer Study could not have found links between breast cancer and all past environmental exposures, since it could only examine levels of persistent organochlorines that were still detectable in women's bodies around the time of diagnosis—long after cancer was initiated."

The Long Island study did report a 50 percent increased risk from polycyclic aromatic hydrocarbons (PAHs), found in vehicle exhaust, cigarette smoke and smoked or grilled foods. Also found in foods is dioxin, an organochlorine. In a 2002 follow-up study of women who had been exposed to dioxin from a 1976 chemical plant explosion in Seveso, Italy, "We found an approximate twofold increased risk for breast cancer among women, associated with a tenfold increase in serum dioxin levels, shortly after the accident," says study coauthor Marcella Warner, Ph.D., a research scientist at the University of California at Berkeley.

In July 2002, a long-term study of estrogen-containing hormone replacement therapy (HRT) was terminated because HRT was found to increase subjects' risk of breast cancer. Looking forward, researchers at Ohio State University are studying whether, in women who eat beef, zeranol, a growth hormone given to cattle, stimulates the proliferation of breast-cancer cells--as it does in lab tests.

Ovarian cancer

Asbestos, linked to ovarian cancer, has been banned as an ingredient in talcum powder since 1973. In a study published in 2000 in the Journal of the National Cancer Institute, Dorota Gertig, Ph.D., and other Harvard researchers questioned nearly 80,000 women about talcum-powder use in 1982, then looked at numbers of ovarian-cancer cases diagnosed in the group by 1996. "We found that women who used talc were not at increased risk of ovarian cancer overall, although there was a modest increase [of about 40 percent] with a particular common subtype of ovarian cancer, invasive serous cancer," says Gertig, now a senior research fellow at the University of Melbourne, Australia. Talc itself has a structure similar to that of asbestos, Gertig says.

A study of 329 ovarian-cancer patients in the July 17, 2002, Journal of the American Medical Association reported an increased risk in women who used estrogen-only replacement therapy, particularly for ten or more years.

Endometriosis

Endometriosis, a painful condition in which tissue lining the uterus spreads to other organs, can cause internal bleeding, scarring and infertility. In a January 2002 report in Environmental Health Perspectives (EHP), Linda Birnbaum, Ph.D., director of experimental toxicology at the EPA, said that a connection with dioxin is "a viable hypothesis, based on animal data and on some human data that is supportive of an association." The good news, Birnbaum says, is that dioxin exposure is going down in the population, "so hopefully endometriosis will become less of a problem."

Premature Puberty

According to a study reported in the September 2002 EHP, Puerto Rican girls who had developed breasts before age eight were found to have higher levels of phthalates-solvents widely used in plastics and personal-care products-in their blood.

Emory University scientists are studying Michigan families who ingested milk and meat contaminated with polybrominated biphenyl (PBB), a flame retardant accidentally mixed into cattle feed in 1973. "We found that the girls who were born to the mothers with the highest PBB exposure, and were also breastfed, had their first menstrual period a year earlier than the unexposed girls," says researcher Michele Marcus, Ph.D. "They also had earlier pubic-hair development, but we did not find earlier breast development."

What you can do

•Use nontoxic cleaners and pest control. (See page 8.)
•Choose personal-care products that don't contain talc and phthalates. (See Green Guide #94.)
•Avoid storing foods and beverages in #3 PVC plastics, which can contain phthalates.
•Choose organic or local produce grown with fewer pesticides, and hormone-free or organic meat. (For brands, see Product Reports at thegreenguide.com.)
•Reduce consumption of fatty animal products, which contain higher levels of dioxins and PCBs.
•Use non-chlorine-bleached paper and sanitary products. (See page 7.)
•Take Action: Ask your congressional representatives to fund more research on environmental exposures and for stricter regulation of polluters. Get involved in efforts to reduce pollution in your community. "The most important thing we can do is to become engaged in the political process at the local level," says Barbara Brenner, executive director of Breast Cancer Action (BCA).

--additional reporting by M. Pennybacker and P. W. McRandle