Have Scientists Really Linked Talcum Powder To Ovarian Cancer?

Talcum powder has been in use for more than a century, and in that time, the soft, absorbent mineral dust has become an element of personal hygiene every bit as essential as a hairbrush. Women started using talcum powder as a feminine hygiene product, either shaking an amount into their underwear or applying the powder directly to the perineum, soon after its introduction to the US market.

But 100 years later, medical researchers have yet to sign off on this particular use. In fact, scientists have been worrying over a potential link between talcum powders and cancer, specifically ovarian cancer, for decades.

Early Warnings: Talc “Embedded” In Tumors

Perhaps their suspicions began as a theory. In the early 1970s, researchers began to suspect that if a powder, like baby powder, was applied directly to the genitals, it might be able to migrate through the reproductive organs, eventually reaching the ovaries.

In 1971, a group of UK researchers led by W.J. Henderson discovered evidence of exactly that. Publishing their results in the Journal of Obstetrics and Gynaecology of the British Commonwealth, Henderson’s team reported on 13 ovarian and cervical cancer tumors, all removed from living patients, which were studded with particles of talc. Was the “world’s softest mineral” responsible for irritating the patients’ ovarian cells, to the point of becoming malignant?

Asbestos & Talc Share Deep Relationship

A similar mechanism had been observed in the case of asbestos fibers. During the 70s, scientists were in the process of conclusively linking asbestos, a widely-used industrial material, to increased cancer risks. Talc, like asbestos, is a silicate mineral. Could it share asbestos’ carcinogenic properties on a chemical level?

Talc Production Mine

Talc ready for processing at a mine.

The intimate relationship between talc and asbestos, however, goes even deeper. Prior to 1976, much of the talc mined from the earth also contained asbestos, because both minerals are often found together in natural deposits. But since few researchers, and fewer industrialists, were worried about asbestos before the 1970s, many products sold as “talcum powder” during the early 20th century also contained fibers of asbestos. While the consumer care industry began to enforce strict screening requirements in 1976, hoping to eliminate asbestos from talc products, the fact that both minerals were once bottled in the same package has come to cloud the debate around talc’s potential link to ovarian cancer.

Cramer’s Harvard Team Discovers Evidence Of Cancer Link

At this time, Henderson’s identification of talc particles in cancerous tumors only served to buttress a theory, namely that powders dusted on the perineum could migrate through a woman’s reproductive organs and potentially irritate her ovarian cells. It still wasn’t clear whether or not women who did so were at an increased risk of actually developing cancer.

Evidence of that possibility would only emerge 11 years later, in 1982. Led by Dr. Daniel Cramer, an epidemiologist at Harvard-affiliated Brigham and Women’s Hospital, a team of academics identified 215 women with ovarian cancer, and another 215 without the disease. Surprisingly, over 42% of the cancer patients reported using talcum powder regularly. Only around 28% of the women without cancer did. After adjusting their data for other potential risk factors, Cramer’s group estimated a 92% increased risk among women who routinely included talc in their hygiene routines.

Even more shocking, women who applied talcum powder in two ways, both as a dusting directly on the perineum and as an application to sanitary napkins, were more than 3 times as likely to develop ovarian cancer.

Talc Research Goes International

Slowly but surely, Cramer’s groundbreaking study set off a flurry of research, inspiring scientists around the world to investigate the “controversial” link between talcum powder and ovarian cancer.

Researchers at Stanford conducted a similar study in 1988, comparing the rate of talcum powder use among 188 female patients with ovarian cancer to the product’s use in 539 women from the general population. Of the cancer patients, 52% used talcum powder regularly. In the group of women without cancer, 46% reported using talcum powder. While lower than Cramer’s result six years earlier, the study’s estimate of a 40% increased risk was statistically significant.

In England, a team from the London School of Hygiene and Tropical Medicine used hospital records to identify 235 women diagnosed with ovarian cancer between 1978 and 1983 and compared them to a pool of 451 women without cancer. Patients who reported using talcum powder “weekly” were twice as likely to have developed cancer. Strangely, women who reported “daily” powder use were only at a 30% increased risk, although several studies have reported no connection between how often a woman uses talcum powder and how likely she is to develop ovarian cancer.

Chinese academics were next, and their findings would shock the medical community further. Comparing 112 ovarian cancer patients in Beijing to 224 women without cancer, a group from Peking Union Medical College found that women who had used talcum powder on the perineum for more than 3 months were nearly 4 times as likely to have been diagnosed with ovarian cancer. Their study, published in a 1992 edition of the International Journal for Epidemiology, was quickly followed by another, and this time, Dr. Daniel Cramer was again involved.

Cramer Finds Risk May Change Based On How, How Often, Women Use Talc

Searching through Boston-area hospitals, Cramer and his colleagues at the Harvard Medical School interviewed 235 women, all of whom had been diagnosed with ovarian cancer between 1984 and 1987, about their use of talcum powder. Turning to the general population, the researchers found 239 women without cancer, asking them if they had regularly used baby powders. Nearly half, 49%, of the women with cancer reported self-exposure to talc, either directly applying the powder to their perineum or shaking it on undergarments, sanitary napkins or diaphragms. A smaller proportion, only 39%, of the disease-free women, who were filtered to match the cancer patients in age, race and socioeconomic level, had regularly used talc.

As a result, Cramer’s group estimated a 50% increased risk for ovarian cancer, but due to some fine-tuning, their study yielded even more detailed results. Women who applied talc:

  • directly as a body powder were at a 70% increased risk
  • on a daily basis were at an 80% increased risk
  • for more than 10 years were at a 60% increased risk
  • more than 10,000 times, and had done so when they were ovulating, were at a 280% increased risk

In their paper, published by the journal Obstetrics and Gynecology in July of 1992, Cramer and his co-authors concluded that while talcum powder may not cause the majority of ovarian cancers, their evidence suggested that the product could increase the risk for cancer.

Talc Migration Theory Returns

One year later, a 1993 paper in the Journal of the American Medical Association (JAMA) presented “intriguing,” albeit understated, data on the habitual use of talcum powder. Dr. Susan Hankinson and her colleagues at Boston’s Channing Laboratory weren’t looking for evidence of the product’s link to ovarian cancer at all. Instead, they analyzed data from the Nurses’ Health Study, one of the nation’s longest-running studies on chronic disease in women, looking for clues to the relationship between tubal ligation or hysterectomy and ovarian cancer.

Medical Researcher In Laboratory

Their study’s sample size was large: 121,700 female nurses had enrolled in the Nurses’ Health Study in 1976, the same year asbestos had been removed from talc products. Each nurse agreed to regular follow-up, so the study’s administrators could monitor relevant health and lifestyle factors closely. The study’s primary goal was to see whether or not tubal ligation and hysterectomy reduced the rate of ovarian cancer and, indeed, both forms of female sterilization were linked to drastic decreases in risk.

Hankinson also noted the body of research linking talcum powder to ovarian cancer, although her paper failed to “highlight” these results, Dr. Ann-Louise Silver would note in a letter to the editor published by JAMA five months later. In her letter, Silver raised a fundamental question: why do hysterectomy and tubal litigation seem to lower the risk for ovarian cancer? Hankinson’s paper proposed few theories to explain the observed decrease, so Silver proposed her own, a theory elegant in its simplicity and one that echoed Henderson’s findings in 1971. Tubal ligation, Silver wrote, could “limit the upward flow” of toxins, essentially cutting off the route through which particles applied to the outer genitals would reach the ovaries. Wasn’t it possible that cutting off that route stopped talcum powder, or other possible carcinogens, from traveling to a patient’s internal reproductive organs?

A European Distinction

In a paper published the same year by the International Journal of Cancer, six Harvard epidemiologists (a group that did not include Dr. Daniel Cramer) reported the results of an interview series conducted between 1989 and 1991 in two Athens hospitals. The team questioned 189 female cancer patients on their use of tranquilizing drugs, painkillers and talcum powder, all of which have been implicated as causal factors in ovarian cancer, and then interviewed 200 random hospital visitors without ovarian cancer.

While their study found that cancer patients were only 5% more likely to have used talcum powder, a result the researcher’s considered statistically insignificant, they noted that “the frequency of reporting talc use was low in the study population.”

Importantly, this study was performed in Greece, where government regulators exert more rigorous restrictions on cosmetic products than those found in the US. Compared to the work of our own Food & Drug Administration, Europe’s regulation of the cosmetic industry is stunning. In the US, only 10 cosmetics have been banned from the market over health risks. Europe has banned a total of 1,372, according to Refinery29. Is talc one of them? Yes, talc-based cosmetics are currently banned throughout the European Union.

In 1995, Australian researchers set out to conduct the largest case-control study on ovarian cancer risk factors ever performed. Interviewing 824 women who had been diagnosed with ovarian cancer between 1990 and 1993, and comparing their answers to 860 “controls,” women who had not been diagnosed with cancer, the team’s results confirmed many previous findings.

Ovarian cancer risks appeared to decrease along with the number of pregnancies a woman experienced, as well as her use of oral contraceptives. Increases in risk were observed along with smoking, a family history of ovarian cancer and “use of talc in the abdominal or perineal region.”

Going Back To Methods

Does how a woman applies talcum powder matter? Talc can be dusted directly on the perineum or used to powder sanitary napkins. Some women store their diaphragms in baby powder, while others use aerosol sprays designed for female hygiene. Does one of those methods appear to heighten the risk for ovarian cancer more than others? Recall that in 1987, Dr. Daniel Cramer found evidence that a direct application of talcum powder could increase the risk for ovarian cancer by up to 70%, much higher than the 50% increase he observed for talcum powder use in general. A decade later, in 1997, a group led by Linda Cook of Seattle’s Fred Hutchinson Cancer Research Center tried to find a new answer to the question of application methods.

Setting up another case-control study, Cook’s team interviewed 313 women who had been diagnosed with ovarian cancer in Washington State, asking them, not only if they had regularly used talcum-based powders, but also how they had applied those powders. The researchers then presented the same questions to 422 women without cancer. Overall, talcum powder use was associated with a 50% increase in the risk for ovarian cancer, but that risk increased to 80% for women who chose to dust their genitals directly with powder.

Lower, but elevated, risks of 50% were observed in relation to two other application methods: powdering sanitary napkins with talcum powders and using genital deodorant sprays. Only one method, storing a diaphragm in powder, was not associated with an increased risk. The results, Cook wrote in a paper published by the American Journal of Epidemiology, “offer[ed] support for the hypothesis, raised by prior epidemiologic studies, that powder exposure from perineal dusting contributes to the development of ovarian cancer.”

Duration & Frequency

Yale University researchers also joined the discussion in 1997, publishing their own case-control study in the journal Cancer. Comparing 450 Canadian women with ovarian carcinomas to 564 members of the general population, Doctors Sandy Chang and Harvey Risch found that women who reported a history of applying talcum powder to the genitals were 42% more likely to have been diagnosed with ovarian cancers. Perhaps more importantly, Chang and Risch also observed a possible relationship between the duration of exposure and an increase in cancers. Although the bump in risk was small, at 9%, and could only be considered of “borderline” significance, this was one of the first studies to suggest that women who had been using talcum powder for years may be more likely to develop ovarian cancer.

Cramer’s 1987 study had also reported a possible link to the duration of application, a modest risk increase of 60% in women who had used powders for more than 10 years, compared to the 50% increase in risk seen among talcum powder users generally. But unlike Cramer’s team, who had identified an even higher risk among women using talcum powders on a daily basis, Chang and Risch found no correlation between cancer and the frequency of powder application in their own data. Thus the authors could not conclude that ovarian cancer was more likely in women who used talcum powder more often, but an association between the length of time a woman had been using the powders was possible.

Researchers at the Roswell Park Cancer Institute in Buffalo, New York came to a conflicting result in their 1999 study of 499 cancer patients and 755 women without cancer. Analyzing interviews on talcum powder usage with each subject, the team found no “significant association” between talcum powder and ovarian cancer, even among women who had been using powders for more than 20 years.

Are Other Risk Factors “Confounding” The Results?

Most well-designed studies attempt to eliminate “confounders,” factors associated with both the exposure under investigation (in this case, talcum powder) and its potential outcome (ovarian cancer). A study published in the journal Obstetrics and Gynecology highlighted this very problem in 1998.

Reviewing 1,206 women who had been studied in previous talcum powder research, Dr. Karen Rosenblatt and her team of public health scientists discovered that people who use talcum powder regularly are also more likely to smoke, drink and rank high on body mass index.

Here’s the problem of confounding in action: if smoking, drinking and having a high BMI are all risk factors for ovarian cancer, then maybe talc users appear to have higher risks of ovarian cancer, not because of the talc, but because they’re more likely to smoke, drink or have a high BMI. Maybe researchers are missing the real risk factor, like a high BMI, because it just happens to be more prevalent in people who use talcum powder, Rosenblatt suggested.

Probably Not.

There are three problems with this line of thinking, according to Dr. Daniel Cramer.

  1. Drinking alcohol has never been linked to an increased risk for ovarian cancer.
  2. While studies suggest that tobacco use may increase the risk for ovarian cancers, smoking has only been linked to a specific type: mucinous ovarian cancers. Studies on talcum powder, however, have observed only a weak relationship between talc and mucinous ovarian cancers. In other words, it seems likely that talcum powder may be able to cause certain types of ovarian cancers, but not the kind that smoking can cause.
  3. Several previous studies have already controlled for BMI and weight in their results. Even after removing these potential confounders from the question, researchers still found a link between ovarian cancer and talcum powder.

And if other factors, rather than exposure to talcum powder, are causing ovarian cancer in these cases, shouldn’t we expect women who use talc-free body powders, like the many products that now contain only corn starch, to be at an equal risk of developing tumors? We should expect that, but it’s not actually the case.

In a 2000 study, toxicologists from the American Health Foundation compared studies on corn starch powders to studies on talcum powder, concluding that “whereas associations between talc exposure and ovarian cancer have suggested but not proved a causal relationship, the application of perineal powder containing cornstarch exclusively is not predicted to be a risk factor for ovarian cancer.”

Evidence “Warrants More Formal Public Health Warnings”

By this time, Dr. Cramer’s work on talcum powder had come under significant attack, primarily from industry-funded groups like the Cosmetic, Toiletry and Fragrance Association (CTFA). Backed by Johnson & Johnson, the nation’s largest manufacturer of talcum-based powders, the CTFA had established its Talc Interested Party Task Force to “develop talking points and find experts to rebut studies linking talc to ovarian cancer,” according to FairWarning.org.

Stethoscope On Book

It’s not surprising, then, that Cramer began his next study, a paper published in the May 1999 edition of the International Journal of Cancer, by noting that “the biologic credibility of the association ha[d] been questioned.” The study itself was a case-control involving 563 patients who had been recently diagnosed with ovarian cancers and 523 women without cancer. Again, Cramer’s research yielded a significant association: after eliminating potential confounders, women who used talc regularly on their genitals were still 60% more likely to have ovarian cancer.

Cramer, though, was not satisfied with simply reporting his results. Gesturing to the wealth of similar studies, all of which had found a significant relationship between talcum powder and ovarian cancer, the researcher and his colleagues ended their paper by writing, “when viewed in perspective of published data on this association, [our new finding] warrants more formal public health warnings.” No such public health warnings would ever appear.

Link Between Talc & Ovarian Cancer “Consistently Demonstrated”

We’re often told that the research around talcum powder remains “inconclusive.” Why, then, did public health researchers from the University of Pennsylvania begin a 2000 study by writing that “previous epidemiologic observations consistently suggest […] that perineal talc use increases the risk” of ovarian cancer? In their paper, published by the journal Epidemiology, the team sought to investigate the theory first proposed by Dr. Henderson in 1971, that particles of talc may irritate cells within the ovaries, thereby increasing the likelihood of malignancy.

But they looked beyond talcum powder, to other conditions that can cause local inflammation of the ovaries, including thyroid disease, pelvic inflammatory disease, endometriosis and ovarian cysts. Each of these inflammatory conditions was associated with an increase in ovarian cancer. So was talcum powder. Even after the researchers controlled for “potentially important confounding factors,” women who regularly applied talcum powder to their underwear were at a 70% increased risk. Women who applied the powder directly to their genitals were at a 50% increased risk.

More evidence of a modestly increased risk for ovarian cancer would follow. In 2003, Harvard researchers returned to the Nurses’ Health Study and found, among a cohort of 78,360 nurses, that women who had used talc powder as a feminine hygiene product were 40% more likely to develop invasive serous ovarian cancer. Studying women in central California, scientists at the Public Health Institute came to a similar result in 2004, finding women who used talc to be 37% more likely to develop ovarian cancer and 77% more likely to develop invasive serous ovarian cancer.

Recent Meta-Analysis Finds 24% Increase In Ovarian Cancer

Noting that several studies had identified a link between ovarian cancer and talc, while others had proved inconclusive, researchers at Brigham and Women’s Hospital in Boston set out to find a definitive answer in 2013. Rather than gather together cancer patients, interview them about their use of talcum powder and compare those findings to women without cancer, the scientists studied other studies. In all, they pooled together the data from eight previous papers, ultimately including 8,525 patients with ovarian cancer and 9,859 patients without the disease.

After a sophisticated statistical analysis, the numbers revealed a real, albeit “modest,” association between the use of baby powders and cancer. Women who said they had used talc regularly as a feminine hygiene product were 24% more likely to develop an ovarian cancer. When the researchers estimated how long, and how often, each woman used baby powder, their findings remained the same. Increasing the frequency of use, in other words, did not appear to increase the risk of developing cancer.

But perhaps most importantly, the study, published in the journal of the American Association for Cancer Research, noted that women who use talcum powder do so for almost purely cosmetic reasons. Every woman in the study, particularly those with ovarian cancer, could have lived without using talcum powder. Sharima Rasanayagam, science director for the Breast Cancer Fund, teased out a similar implication, speaking to Yahoo! in February 2016, when she said, “we take a precautionary approach, especially because it’s not a product you need to be using. Why increase your risk for these cancers at all?”