The risk of ovarian cancer was one-third higher among women who regularly powdered their genitals with talc, a recent study found.
Researchers asked 2,041 women with ovarian cancer and 2,100 similar women without ovarian cancer about their talcum powder use. Those who said they routinely applied talc to their crotches, sanitary napkins, tampons and underwear had a 33 percent higher risk of ovarian cancer, according to a report in Epidemiology.
Lead author Dr. Daniel W. Cramer, who heads the Obstetrics and Gynecology Epidemiology Center at Brigham and Women's Hospital in Boston, has unsuccessfully called for warning labels on talcum powder.
"This is an easily modified risk factor," he told Reuters Health by phone. "Talc is a good drying agent, but women should know that if it's used repeatedly, it can get into the vagina and into their upper genital tract. And I think if they knew that, they wouldn't use it."
Cramer first reported a link between genital talc and ovarian cancer in 1982. But the current study is the first to confine the association to premenopausal women and to postmenopausal women who used hormone therapy - which might help explain earlier contradictory results on the link between talc and ovarian cancer, Cramer and his team write.
Cramer has testified as a paid expert in lawsuits against talcum powder makers. A St. Louis jury last week ordered Johnson and Johnson to pay $72 million in damages to the family of Jacqueline Fox. After using the company's Baby Powder and Shower to Shower for more than 35 years, Fox died from ovarian cancer last year at age 62.
Johnson and Johnson maintains that scientific evidence shows that talc - long marketed for babies' bottoms - is safe. "With over 100 years of use, few ingredients have the same demonstrated performance, mildness and safety profile as cosmetic talc," a company statement says.
Talc is a moisture-absorbing mineral made of magnesium, silicon and oxygen. In its natural form, it may contain asbestos, a known carcinogen. But all commercial products sold in the U.S. have been asbestos-free since the 1970s.
About 20,000 American women are diagnosed with ovarian cancer and about 14,500 die from it annually, according to the Centers for Disease Control and Prevention (CDC).
In 2006, the World Health Organization's International Agency for Research on Cancer classified genital talc as possibly carcinogenic.
Nonetheless, the CDC does not list talc as a risk factor for ovarian cancer.
Dr. Nicolas Wentzensen, head of the clinical epidemiology unit for the National Cancer Institute, told Reuters Health by email that the new study strengthens the evidence linking genital talc to the deadly reproductive cancer. He was not involved with the current study.
"The recent paper in Epidemiology has provided additional support for an association between talc use and ovarian cancer from a case-control study," he wrote.
Still, Wentzensen isn't fully convinced of the link because even this new study was not of the most rigorous possible design. So-called prospective cohort studies would be particularly strong, he noted, because they would assess exposure at the start of an investigation and follow participants over time to see if they develop the disease.
"Scientific consensus emerges over time, especially in cases like this, where the results have been somewhat inconsistent," he said. "While this recent analysis provides additional evidence supporting an association of talc and ovarian cancer, it will be important to test the methods used in this analysis in other data to see if the findings are confirmed."