Using body powder in the genital area doesn't raise the risk of developing ovarian cancer, according to the authors of the biggest-ever study on the controversial practice.
The study published in the journal JAMA involved 252,745 women from four separate U.S. cohorts who were aged 57 on average. 38 percent said they applied powders such as talcum, baby or deodorizer to their genital area.
Of those, 10 percent had used it long-term, which the team defined as at least 20 years. A further 22 percent administered it frequently, meaning at least once per week; once per week in the past year; or often between the ages of 10 and 13. After an average of 11.2 years, a total of 2,168 of the total women had developed ovarian cancer.
Study co-author Katie M. O'Brien of the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina, told Newsweek the study was the largest to date on the subject.
"The study found no statistically significant association between genital powder use and ovarian cancer," she said.
In a practice that has fallen out of fashion over the past five decades—according to a commentary accompanying the paper in the journal JAMA—some women apply powder either directly to their genital area or to their underwear or menstrual products to absorb odor and moisture. Talc powder is among such products used, which up until a ban in 1976 was at risk of containing the carcinogen asbestos as they occur together in nature.
But high-profile lawsuits, such as women being awarded nearly $5 billion over claims talc products caused cancer, may affect what is known as recall bias and pose problems for researchers investigating the practice, the authors explained. Recall bias is where a participant incorrectly remembers a past event, like using talc.
The World Health Organization's International Agency for Research on Cancer has previously stated talc which contains asbestos is carcinogenic, while inhaled products not containing talc are "not classifiable as to carcinogenicity in humans."
In 2010, the organization said it was possible that talc-based products could cause cancer, its weakest classification. This conclusion was based on what is known as case-control research, which could be affected by recall bias, Kevin McConway, emeritus professor of applied statistics at The Open University who wasn't involved in the JAMA study or the IARC research, said in a statement. This means the body felt the evidence wasn't very clear, he said.
O'Brien told Newsweek the researchers will continue to follow the women to track whether any others develop ovarian cancer.
Experts in the field not involved in the project welcomed the study and praised the team's methods, but highlighted the difficulties of exploring this topic.
Dr. Dana R. Gossett, and Dr. Marcela G. del Carmen, who didn't work on the paper, wrote the commentary published in the journal JAMA. They said the study was "rigorously conducted" and future research would be "strengthened by focusing on women with intact reproductive tracts, with particular attention to timing and duration of exposure to powder in the genital area."
Justin Stebbing, professor of cancer medicine and medical oncology at Imperial College London, described the study in a statement as a "very well conducted rigorous investigation."
"There weren't many cases of ovarian cancer in the group so it's possible a small effect has been missed, but it doesn't look like talc is a carcinogen which is an important and reassuring finding, especially as they also looked at duration and frequency of use, again finding no causative effects," he said.
McConway said there is still uncertainty about whether an association exists between powders and ovarian cancer. If it does exist, it's unclear about whether the powder itself is what causes any increase in cancer risk, he said, as well as what the size of the risk increase is—if it there is one.
"But what the research does establish, I'd say, is that if using talc or other powder on that part of a woman's body does really increase the risk of ovarian cancer, the increase in risk is likely to be small. I'm not a woman, so can't have concerns about my own health in these respects. But if I were a woman, this wouldn't be high on my list of worries," he said.
Professor Iain McNeish, director of the Ovarian Cancer Action Research Centre at Imperial College London, commented: "This is a very well-conducted study by a highly respected group of researchers. Proving causation links of this type is incredibly difficult and the authors are very careful to highlight the potential limitations of their study.
"However, this research is robust, analysing data from 250,000 women followed for an average of over 11 years, and has concluded there is no statistically significant relationship between talc use and the development of ovarian cancer," said McNeish,
