In recent years, a number of lawsuits have highlighted concerns regarding a possible link between ovarian cancer risk and the use of talc-containing cosmetic powders in the genital area. However, a large pooled analysis now published in JAMA reports no statistically significant association between genital powder use and ovarian cancer.
The potential connection between genital powder use and ovarian cancer risk was first investigated because of the relationship between talcum powder and asbestos, a known carcinogen which is often naturally found in the same locations as talc and can contaminate talc during the mining process. Asbestos was banned from all US-based manufacturing of cosmetic talc in 1976. Case-control studies have reported a correlation between ovarian cancer and ever use of powder in the genital area; however, these data were based on participant recollections and therefore may have been impacted by bias, particularly in light of the media coverage of talc-related lawsuits.
The investigators of the current pooled analysis examined data from four large, US-based cohorts, including the Nurses' Health Study, which enrolled 81,869 women in 1976 and followed them from 1982 to 2016; the Nurses' Health Study II, which enrolled 61,261 women in 1989 and followed them from 2013 to 2017; the Sister Study, which enrolled 40,647 women between 2003 and 2009, with follow-up between 2003 and 2017; and the Women's Health Initiative Observational Study, which enrolled 73,267 women between 1993 and 1998, with follow-up between 1993 and 2017.
In total, the pooled sample comprised 252,745 women, with a median baseline age of 57 years. Thirty-eight percent of study participants self-reported powder use in the genital area, with 10% reporting long-term use and 22% reporting frequent use. Participants were followed for a median of 11.2 years.
During follow-up, 2,168 women in the sample developed ovarian cancer, which translated to 58 cases per 100,000 person-years. The incidence of ovarian cancer was slightly higher among ever users compared with never users (61 cases vs 55 cases per 100,000 person-years), for an estimated risk difference at age 70 of 0.09%. Estimated hazard ratios were 1.09 for frequent use compared with never use and 1.01 for long-term use versus never use.
A possible positive association was found in women with patent reproductive tracts (women who had not undergone hysterectomy or tubal ligation), with a hazard ratio of 1.13; however, the association did not reach statistical significance.
"This observation [of a potential association with patent reproductive tracts] lends support to the hypothesis that powder with or without asbestos could irritate and inflame the reproductive tract, as patency is required for there to be a direct physical path between the genitals and the fallopian tubes or ovaries," note the researchers in their publication, led by first author Katie O'Brien, PhD, a staff scientist in the Epidemiology branch of the National Institute of Environmental Health Sciences.
"There was not a statistically significant association between self-reported use of powder in the genital area and incident ovarian cancer," conclude the authors. "However, the study may have been underpowered to identify a small increase in risk."
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