Two years ago, I wrote an article in this column regarding the question of the risk of ovarian cancer in women who had used baby powder containing talc for drying their genital areas after bathing (“Baby Powder and Ovarian Cancer,” Sept. 8, 2022, https://bit.ly/3YSInq2). This concern was originally raised in a study by Daniel Cramer, an epidemiologist at Harvard, who conducted a case-control study that was published in 1982, that reported a relative risk of 1.9 (a 90% increased risk) for the approximately 40% of women who reported using baby powder.
In subsequent years since 1982, at least 15 additional studies were conducted and reported, most of which also reported an increased risk of ovarian cancer, although the results were not entirely consistent. A meta-analysis that averaged the results of all the studies conducted up to that point in time came up with an average increased risk of 1.3, i.e., a 30% increased risk for those who reported using baby powder.
A limitation or weakness of these studies was that virtually all of them were case-control studies. They almost all relied on self-report of the use of the baby powder. Remember that a case-control study compares those with the disease, ovarian cancer patients, to healthy controls, those without the cancer. Thus, the ovarian cancer study subjects, at the time at which the interviews were conducted, were likely to be aware of the hypothesis of the study. This could therefore lead to what is known as recall bias—the tendency of a case to be more likely than a control to respond affirmatively to a known risk factor. Furthermore, lawsuits against the baby powder manufacturers, primarily Johnson & Johnson, were contemplated fairly early and, therefore, the cases might also have been inclined to answer affirmatively as well in order to participate in a lawsuit; this is known as litigation bias.
Indeed, as I mentioned in my prior article two years ago, several large lawsuits have been undertaken and adjudicated mostly in favor of the plaintiffs and with very large awards. Johnson & Johnson has become nearly bankrupt as a result of the awards in this area.
Another development has been the discovery that asbestos has been present in small amounts in the talcum powder. This has helped to clarify the possible carcinogenic mechanism by which the baby powder was causing the ovarian malignancy. So I would state that it has reinforced the causal mechanism and biological plausibility arguments.
But I come back to this topic again because now, in addition to the prior case-control studies, a new cohort study has been published in JAMA that adds to the available data on this interesting subject. A cohort study is a study in which the interviews with the subjects would be undertaken prior to the occurrence of the outcome, in this case ovarian cancer. Thus, while one still has the study limitation that the exposure definition is based on self-report by the study subject, which of course may be imprecise, at least the subject is unaware of whether she is fated to develop ovarian cancer or not. Therefore, the two major potential study biases of recall bias and litigation bias would not or could not be operational or able to affect the study’s results.
The Sisters Study is a cohort study that was conducted by investigators from the National Institute of Environmental Health Sciences. They recruited 50,884 women 35-74 years of age between 2003 and 2009 who had a sister previously diagnosed with breast cancer, but who were cancer-free themselves. The participants filled out questionnaires on multiple subjects. For our purposes, they were queried regarding how frequently they applied talcum powder to their genital area between the ages of 10 and 13 years and during the 12 months prior to enrollment in the study.
These women were followed through 2021 and all cases of ovarian cancer, breast cancer and uterine cancer determined. Various statistical corrections were made to try to minimize recall bias and to correct for missing data. The final estimate was that 40% of the women were categorized as users of genital talc. In the analysis of its association with the subsequent incidence of ovarian cancer, after controlling for a wide variety of demographic and hormonal variables, the relative risk was 1.82 (95% confidence interval 1.36-2.43). No associations were observed with either breast cancer or uterine cancer incidence.
Given the above, I think this recent study reinforces the previous studies regarding the use of genital talcum powder and risk of ovarian cancer. The risk was mainly present for those using this product in the 20-39 year age range.
Alfred I. Neugut, MD, PhD, is a medical oncologist and cancer epidemiologist at Columbia University Irving Medical Center/New York Presbyterian and Mailman School of Public Health in New York. Email: [email protected].
This article is for educational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment, and does not constitute medical or other professional advice. Always seek the advice of your qualified health provider with any questions you may have regarding a medical condition or treatment.
