Incidence of Hormone-Related Cancers and Intimate Care Products

Introduction

In recent years, there has been an increasing concern about the safety of intimate care products that may contain potential endocrine disrupting chemicals, such as phthalates, parabens, and bisphenols. These chemicals are believed to alter endogenous hormone levels, influencing the risk of hormone-related diseases such as breast cancer, ovarian cancer, or uterine cancer. Also, these products might contain other known or suspected carcinogens, such as volatile organic compounds and asbestos.

Although previous studies have shown that the use of genital talcum powder is associated with ovarian cancer, these conclusions are marred by recall bias and misclassification of exposure. This research aims to reassess the relationship between the use of intimate care products and the incidence of hormone-related cancers in women, taking into account potential bias factors in the data.

Source of the paper

The principal authors of this paper include Katie M. O’Brien, Nicolas Wentzensen, Kemi Ogunsina, Clarice R. Weinberg, Aimee A. D’Aloisio, Jessie K. Edwards, and Dale P. Sandler. They are from the National Institute of Environmental Health Sciences (NIEHS) and the National Cancer Institute (NCI). This paper was published in the Journal of Clinical Oncology on May 15, 2024, with a DOI number https://doi.org/10.1200/jco.23.02037.

Research Methods

Study Participants

The data for this study comes from the “Sister Study”, which involves 50,884 women aged between 35 and 74 years who do not have breast cancer, but whose sisters do. The participants all live in the US and have provided written informed consent.

Data Collection

Data on use of genital talcum powder and douching was collected at enrollment (2003-2009) and during follow-up (2017-2019). Relations between the use of intimate care products and breast cancer, ovarian cancer, and uterine cancer were estimated using Cox proportional hazards models, and quantitative bias analysis was performed to account for potential exposure misclassification and recall bias.

Exclusion Criteria

Five women who dropped out of the study and 79 women diagnosed with breast cancer or with an unclear status were excluded. An additional 994 women were excluded due to missing key covariates. This left a total of 49,806 women included in the study. For the ovarian cancer analysis, an additional 225 women were excluded as having unclear status or diagnosed with ovarian cancer, and also 8,753 women who had undergone bilateral oophorectomy. For the uterine cancer analysis, 416 women with unclear status or previously diagnosed with uterine cancer were excluded, along with 15,202 women who had previously undergone a hysterectomy.

Exposure Assessment

Participants were asked in a questionnaire how often they used douching and talcum powder between the ages of 10-13 and in the 12 months prior to admission. The research focused mainly on the use of douches and genital talcum powder before enrollment, as well as their frequency, duration, and timeframe of use.

Results

In different scenarios, between 41%-64% of the participants reported having used douches, and 35%-56% reported having used genital talcum powder. Models adjusting for exposure misclassification showed that the use of genital talcum powder was positively associated with ovarian cancer (with a hazard ratio, HR, between 1.17 and 3.34). The frequent use of douches and their use in adolescence were also positively associated with ovarian cancer, but there were no clear connections with breast or uterine cancer for either douches or talcum powder. Despite differential reporting introducing positive bias, the adjusted estimates still supported a positive association between genital talcum powder and ovarian cancer.

For example, when assuming a reclassification of 25% exposed cases and 10% unexposed controls, the HR is 1.40 (95% confidence interval, 1.04 to 1.89).

Conclusion

Results indicated that even though differential recall might overestimate the measurements, adjustment still supports a positive correlation between intimate care products’ use (including genital talcum powder) and ovarian cancer. However, these findings do not reveal specific carcinogenic mechanisms or components. Future research should focus on identifying the potential biological mechanisms and specific carcinogens.

Research Highlights

1. Key Findings: A positive association between the use of genital talcum powder and ovarian cancer is the key discovery, supplementing existing research evidence.
2. Broad Data Coverage: The study uses a large size, long-term follow-up data to comprehensively assess the use of intimate care products.
3. Quantitative Bias Analysis: With several bias analysis models