Vaginal powder use results in 50% increased risk for ovarian cancer, study suggests.

VAGINAL POWDER DUSTING, DEODORANT SPRAY "MODEST" EFFECT ON OVARIAN CANCER found by a study published in the March 3 issue of the American Journal of Epidemiology. "Our results suggest that a history of perineal dusting or use of genital deodorant sprays has a modest influence on the development of epithelial ovarian tumors," authors Linda Cook, Mary Kamb and Noel Weiss, University of Washington, report.

Cook et al. conducted a case-control study evaluating 313 women with ovarian cancer from western Washington state and 422 ovarian cancer-free women from the same region. The women were questioned about powder use via four possible exposure routes: storing diaphragms in powder, dusting the perineal area with powder post-bathing, powdering sanitary napkins and using genital deodorant sprays.

Powder-users, defined as "women who reported any method, type or frequency" of powder application, were asked follow-up questions to ascertain exposure duration, frequency of application and type of powder used (cornstarch, talcum powder, baby powder, deodorant powder, scented body/bath powder).

The epidemiologists used logistic regression to determine the relative risk for ovarian cancer associated with genital powder application. Researchers calculated relative risk for "women who reported exclusive use" of a single powder application method; risk "among women who reported any use of the four methods"; and risk by "exclusive and nonexclusive use" by type of powder.

Data were also adjusted for education, income, marital status, body mass index, oral contraceptive use and parity; this adjustment "did not alter the estimated relative risks," Cook et al. report. However, less education, lower household income and higher body mass index "were more common among women with ovarian cancer," while use of oral contraceptives and full-term births "were less common" in the sample of women with ovarian cancer.

For women who used only one method of genital powder application, "ovarian cancer risk was most strongly elevated among those who dusted perineal areas with powder after bathing," the study concludes.

"Perineal dusting was associated with an increased risk of ovarian cancer...although there was no clear pattern of increasing risk with increasing duration of use," the study states. The researchers cite an age-adjusted relative risk of 1.8 with a 95% confidence interval range of 1.2-2.9.

"The use of genital deodorant sprays was also associated with an elevated ovarian cancer risk," the researchers report, with an age-adjusted relative risk of 1.9 (95% CI = 1.1-3.1). Fifteen deodorant spray users "with the strongest elevation in risk" used the sprays for more than one year, the study states.

Cook et al. note that the deodorant spray "preliminary results require confirmation in other studies" because "it is difficult to postulate that an increased risk for ovarian cancer may specifically be due to powder and associated constituents when some of the deodorant sprays do not contain aerosolized powder." The study states: "It is possible that...other unidentified chemical substances present in deodorant sprays...may influence the development of ovarian cancer."

Storing a diaphragm in powder or applying powder to sanitary napkins "was not related to the risk of developing an ovarian tumor," according to Cook et al.

For all forms of powder use, "there was an overall 50% elevation in risk for ovarian cancer" (95% CI = 1.1-2), according to the study. Of the women with ovarian cancer, 50.8% applied powder to the genital area compared to 39.3% of the control population, the investigators state.

While "no specific type of powder...was strongly related to ovarian cancer risk...there was a suggestion of elevated risk associated with any use of talcum powder and bath/body powders," the researchers state.

Concern over talc safety has been brewing for almost five years. The scare over the potential for increased ovarian cancer risk due to perineal talc exposure first surfaced in 1992 in a Harvard Medical School study citing a "modest" association between talc and ovarian cancer. Additional talc safety concerns were raised following the release of a National Toxicology Program talc inhalation study that reported "clear evidence" of carcinogenicity in female rats. FDA, in its review of the study, attributed the positive results to an "overloading" dose of smaller-than-cosmetic grade talc ("The Rose Sheet" Nov. 7, 1994, p. 4).

FDA is reviewing a citizen petition from the Chicago-based Cancer Prevention Coalition that requests carcinogenicity warnings on talc-containing products ("The Rose Sheet" Dec. 5, 1994, p. 6). The Cosmetic, Toiletry and Fragrance Association has disputed the basis for such a warning ("The Rose Sheet" June 26, 1995, p. 2).

Addressing limitations in the study, Cook et al. note that use of condoms packed in talc could have contributed to genital powder exposure. "There was insufficient information...to address the influence of condom use on the risk for ovarian cancer." Furthermore, the study notes, "the specific constituents of powders that may influence the development of ovarian cancer is unknown, although attention has been focused on fibrous talc particles and asbestos."

The researchers recommend cohort studies to more accurately determine the prevalence of genital powder use; the control group in the Cook et al. study and similar studies show genital powder exposure varying from 28% to 51% of women. "These studies could eliminate concerns regarding the potential differences in the reporting of genital powder exposures between cases and controls."