A study of more than 250,000 women found that those who used talc or other personal-hygiene powders weren't significantly more likely to develop ovarian cancer, news that will affect thousands of legal claims against drugmaker Johnson & Johnson over the products.
The U.S. government-sponsored study, published in the Journal of the American Medical Association on Tuesday, is one of the biggest to date to examine whether women who used the powder products on their genitals are at increased risk of developing the deadly cancer years later.
While the study has some limitations and couldn't rule out the powders as a cause, the findings suggest that if a risk exists, it's quite small.
"Overall, women can be very reassured by this," said Dana Gossett, chief of obstetrics and gynecology at the University of California, San Francisco, who co-authored an editorial accompanying the new research. "The use of genital powders is unlikely to cause a significant increase in ovarian cancer risk."
Health products giant Johnson & Johnson is facing nearly 17,000 lawsuits contending that asbestos-tainted, talc-based personal hygiene products caused women's ovarian cancers and other malignancies. While the research won't eliminate the company's legal exposure, it may help bolster J&J's argument that the link between talc and ovarian cancer found in some previous studies isn't beyond dispute.
"Another study has found there is no statistically significant association between use of talc for feminine hygiene and ovarian cancer," said Kimberly Montagnino, a J&J spokeswoman.
The lawsuits have hurt J&J shares as investors weighed the billions of dollars in potential legal risk to the New Brunswick, N.J.-based company.
The new research pooled data from four studies that followed more than 250,000 women for over a decade. Eventually, 2,168 of the women developed ovarian cancer.
Women in the analysis who reported ever using powder on their genitals had an 8% higher risk of developing ovarian cancer years later compared to women in the studies who said they never used powder on their genitals. This small difference was not considered statistically significant, meaning that under scientific standards there's a reasonable possibility the result could have been caused by chance.
When researchers looked at women who had used genital powder for long periods of time, or more frequently — questions that were asked in some but not all the component studies — there was also no evidence of a strong ovarian cancer risk.
"We found a small positive, but not statistically significant association," said lead author Katie O'Brien, an epidemiologist at the National Institute of Environmental Health Sciences in North Carolina. "It's pretty ambiguous."
A federal judge is weighing whether the science backing up thousands of ovarian claims tied to baby powder is legitimate, a decision with broad ramifications for how the cases will proceed.
U.S. District Judge Freda Wolfson in Trenton, N.J., is overseeing a consolidation of more than 12,000 baby powder cases filed in federal courts across the U.S. Wolfson must decide whether experts hired by the women suing J&J used reliable methods to conclude the company's talc-based products contained asbestos, and that exposure could have caused their ovarian cancers.
According to court filings by J&J's lawyers, the idea that talc — even untainted by asbestos — can cause ovarian cancer isn't supported by science.
The company's lawyers have sought to persuade juries that women's cancers were caused by other factors including genetics and lifestyle. J&J has been on a roll at trial recently, winning eight defense verdicts in talc cases last year while losing five.
Overall, "it is not great data," conceded O'Brien, the study author. But given how hard it is to study rarer tumors like ovarian cancer, it may be the most detailed data researchers get anytime soon. "It is the biggest study and probably will be for a very long time," she said.