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In recent years, women have taken talcum powder manufacturers to court because of the concern that the use of the product in the genital area may cause ovarian cancer. Now, a new study finds no significant association between the use of talc or other powders and ovarian cancer.
Researchers at the NIH National Institute of Environmental Health Sciences and the National Cancer Institute conducted the largest study to date of use on genital powder and ovarian cancer. The study, published on Tuesday in JAMA It uses data from 252,745 women who answered questions about whether the powder was used on their genitals. This was a combined analysis of four large studies collecting data on the frequency and duration of time that women used the powder.
According to epidemiologist Katie O & # 39; Brien, who led the study, women report applying the powder directly to their genital area or sanitary pads, tampons, underwear or diaphragms. O & # 39; Brien doesn't know exactly what kind of dust women use. It could have been talcum powder alone, corn starch alone or a combination of both.
The research findings that women who had used powder had an 8% higher risk of ovarian cancer compared to those who never used it. "That is not a statistically significant increase," says O & # 39; Brien. And he adds that this increase has to be understood in context. Ovarian cancer is very rare and the lifetime risk of getting it is 1.3%, so an increase of 8% is "small". O & # 39; Brien says it represents a 0.09% increase in estimated risk at 70 years.
But among the subgroup of women who had the uterus and fallopian tubes intact, their highest risk of ovarian cancer from using dust in their genital area was 13%, which is an estimated 0.15% increase in risk to 70 years and still considered very small increase
Unlike most other studies of talc and ovarian cancer, which focused on women who have been diagnosed with cancer, this study was prospective, and asked about the use of dust before the study subjects had developed ovarian cancer. This means that the study is free of memory biases, says O & # 39; Brien. It eliminates the possibility that study subjects "search for reasons why they have ovarian cancer, and may over-report on certain things they have heard may be associated with it."
Dust consumption rates have declined over the past 50 years, but it is still common practice for some women, says Dr. Dana Gossett, a professor of obstetrics and gynecology at the University of California, San Francisco. She wrote an editorial that accompanies the study but did not participate in the study itself.
"Women have powders used for genital hygiene for decades to absorb odors and moisture," she says.
Previous research into an association between the use of talcum-containing powders for genital hygiene and the risks of ovarian epithelial cancer has provided inconsistent results, says Gossett, and has resulted in a "continuing controversy." Concerns have been raised about the possible contamination of mineral talc with asbestos, a known cancer risk. Most powdered products include some mineral talc.
The researchers say that it has been the hypothesis that dust could induce an inflammatory response by irritating the epithelial tissue of the ovary or fallopian tubes directly which, in turn, could trigger a cascade of increased levels of oxidative stress, damage of DNA and cell division, all of which could contribute to carcinogenesis
Gossett says the new study finding "doesn't really admit any association [of powder use with ovarian cancer]".
"No study can ever say what the cause of cancer is, but this study shows that at least it is not a substantial increase in the risk of ovarian cancer," she says.
The study has several limitations. The researchers were unable to document the frequency or how long the women used powder nor were they able to identify exactly what ingredients were in the powder. It also mainly included white women. As an anecdote, black women are more likely to dust baby use.
Obstetrician Gossett says the results of the study should be "reassuring to women that if they are opting for the use of powders on their genitals they are not doing something horrible."
Gossett also notes that due to the small number of cancer cases in the data, the study was "low potency." She suggests that future analyzes would be strengthened, focusing on women with intact reproductive tracts, with special attention to time and duration of exposure to dust in the genital area.
Meanwhile, since there is no medical reason for the use of talcum powder, researcher O & # 39; Brien suggests that women weigh perceived benefit with possible risk. Study participants will continue to be followed to continue the development of ovarian cancer in the future, she says.