Compendio degli studi più significativi con riferimento a proprietà, assunzione, effetti.

Non vi è unanimità di conclusioni, da parte della letteratura scientifica, sulla pericolosità e genotossicità del talco, per cui abbiamo raccolto in due sezioni gli studi che ritengono il talco non dannoso per la salute umana e gli studi che attribuiscono al talco evidenti conseguenze negative.

Talco non pericoloso

Hildick-Smith GY. The biology of talc. Br J Ind Med. 1976 Nov;33(4):217-29. doi: 10.1136/oem.33.4.217. 

Abstract. Data are presented on the effects on health of talc dusts from exposure in industry and use of talc-containing health products. The mineralogy of talc and the composition of cosmetic and industrial grade talc dusts are described. Studies in animals are reviewed, and epidemiological data are considered in relation to exposures that occur during industrial and consumer uses of talc dusts. Hamsters exposed to 8 mg/m3 of respirable cosmetic grade talc dust for up to 150 minutes a day for 300 consecutive days showed no difference in incidence or nature of pathological lesions from those observed in a group of untreated animals. A retrospective study of the causes of death of 227 talc mine millers exposed to cosmetic grade talc at the threshold limit value for talc (20 million parts per cubic foot) for an average of 15-8 years showed that the causes of death were no different from those in a control cohort not exposed to talc dust. The available data indicate that talc dust exposure in the modern mining of cosmetic grade talc does not appear to be injurious to health. The significantly lower dust exposure in the normal use of cosmetic grade talc dusts in talc-containing health and cosmetic products confirms that their use is not a hazard to health.

Muscat JE, Huncharek MS. Perineal talc use and ovarian cancer: a critical review. Eur J Cancer Prev. 2008 Apr;17(2):139-46. doi: 10.1097/CEJ.0b013e32811080ef. 

Abstract. Talc, like asbestos, is a silicate that has been studied in relation to cancer risk. Several studies conducted over the past 25 years found an association between perineal talc powders and ovarian cancer. The summary relative risk is about 1.3 (95% confidence intervals 1.2-1.5) and these data have been interpreted as supporting a causal role. In this review article, we discuss the chemical and morphological features of talc and asbestos, and explain why despite their similar chemical classification talc does not possess asbestos-like carcinogenic properties. The heterogeneity in the perineal dusting studies has raised important concerns over the validity of the exposure measurements, and the lack of a consistent dose-response effect limits making causal inferences. Perhaps more importantly, whereas it is unknown whether external talc dust enters the female reproductive tract, measures of internal talc exposure such as talc-dusted diaphragms and latex condoms show no relationship with ovarian cancer risk. In addition, the therapeutic use of high dose cosmetic grade talc for pleurodesis has not been shown to cause cancer in patients receiving these treatment modalities. Talc is not genotoxic. Mechanistic, pathology and animal model studies have not found evidence for a carcinogenic effect. In summary, these data collectively do not indicate that cosmetic talc causes ovarian cancer.

Fiume MM, Boyer I, Bergfeld WF, Belsito DV, Hill RA, Klaassen CD, Liebler DC, Marks JG Jr, Shank RC, Slaga TJ, Snyder PW, Andersen FA. Safety Assessment of Talc as Used in Cosmetics. Int J Toxicol. 2015 Jul-Aug;34(1 Suppl):66S-129S. doi: 10.1177/1091581815586797.

Abstract. The Cosmetic Ingredient Review Expert Panel (Panel) assessed the safety of talc for use in cosmetics. The safety of talc has been the subject of much debate through the years, partly because the relationship between talc and asbestos is commonly misunderstood. Industry specifications state that cosmetic-grade talc must contain no detectable fibrous, asbestos minerals. Therefore, the large amount of available animal and clinical data the Panel relied on in assessing the safety of talc only included those studies on talc that did not contain asbestos. The Panel concluded that talc is safe for use in cosmetics in the present practices of use and concentration (some cosmetic products are entirely composed of talc). Talc should not be applied to the skin when the epidermal barrier is missing or significantly disrupted.  © The Author(s) 2015.

Talco pericoloso

Tran TH, Steffen JE, Clancy KM, Bird T, Egilman DS. Talc, Asbestos, and Epidemiology: Corporate Influence and Scientific Incognizance. Epidemiology. 2019 Nov;30(6):783-788. doi: 10.1097/EDE.0000000000001091. 

Abstract. Despite the Cosmetic, Toiletry, and Fragrance Association’s attempts to downplay the elevated risks of ovarian cancer associated with perineal talcum powder use reported in epidemiologic studies, both of the National Toxicology Program scientific panels voted to list talc “not containing asbestos” as a carcinogen. The Cosmetic, Toiletry, and Fragrance Association then threatened the United States National Institutes of Health and National Toxicology Program Report on Carcinogens budgets,and the National Toxicology Program management overruled the science panels. Talc was the only one of the 21 substances nominated for the Report on Carcinogens that the National Toxicology Program withdrew.

Cramer DW. The association of talc use and ovarian cancer: biased or causal. Gynecol Oncol Rep. 2021 Dec 4;41:100896. doi: 10.1016/j.gore.2021.100896. 

Abstract. In a recent review published in Gynecologic Oncology (Wentzensen and O'Brien, 2021), Wentzensen and O’Brien summarized epidemiologic evidence on the association between genital talc use and ovarian cancer. They noted that retrospective case-control studies have shown associations between genital powder use and ovarian cancer with summary relative risk estimates from 1.24 to 1.35. ... The apparent synergistic effect of estradiol with talc provides a biologic basis for our observation that postmenopausal women using estrogen replacement had greater risk for a ovarian cancer with talc use than postmenopausal women who had used talc but hadn’t taken hormone replacement.

Chang CJ, Tu YK, Chen PC, Yang HY. Talc exposure and risk of stomach cancer: Systematic review and meta-analysis of occupational cohort studies. J Formos Med Assoc. 2020 Apr;119(4):781-792. doi: 10.1016/j.jfma.2018.07.015. 

Abstract.  Background/purpose: Talc powder is widely used in various industries, but the carcinogenic effects associated with talc are not well understood. The objective of this study was to estimate the risk of stomach cancer after occupational talc exposure....Conclusion: The available data showed a positive association between occupational talc exposure and risk of stomach cancer. The association between talc not containing asbestiform fibers and risk of stomach cancer was not significant. Further epidemiological studies are required to evaluate the safety of talc. Copyright © 2018. Published by Elsevier B.V.

Moline J, Patel K, Frank AL. Exposure to cosmetic talc and mesothelioma. J Occup Med Toxicol. 2023 Jan 18;18(1):1. doi: 10.1186/s12995-023-00367-5. 

Abstract.  Aim: Mesothelioma is associated with asbestos exposure. In this case series, we present 166 cases of individuals who had substantial asbestos exposure to cosmetic talc products as well as some who had potential or documented additional exposures to other asbestos-containing products and who subsequently developed mesothelioma....Conclusion: Cumulative exposure to asbestos leads to mesothelioma; for individuals with mixed exposures to asbestos, all exposures should be considered. Use of cosmetic talc is often overlooked as a source of asbestos exposure. All individuals with mesothelioma should have a comprehensive history of asbestos exposure, including cosmetic talc exposure. © 2023. The Author(s).

Stoiber, T., Fitzgerald, S., & Leiba, N. S. (2020). Asbestos contamination in talc-based cosmetics: An invisible cancer risk. Environmental Health Insights, 14, 1178630220976558.

Abstract. The aim of this study was to assess asbestos contamination in talc-based cosmetics and to call attention to the outdated methods for screening as well as bring awareness to the potential hazard in cosmetics. With nearly 15% of products contaminated in a small study, methods used by industries to screen talc supplies are not adequate.

Steffen, J. E., Tran, T., Yimam, M., Clancy, K. M., Bird, T. B., Rigler, M., ... & Egilman, D. S. (2020). Serous ovarian cancer caused by exposure to asbestos and fibrous talc in cosmetic talc powders—a case series. Journal of Occupational and Environmental Medicine, 62(2), e65-e77.

Abstract. Objective: Asbestos is a known cause of ovarian cancer. We report 10 cases of serous ovarian cancer among users of Johnson & Johnson (J&J) asbestos-containing “cosmetic” talc products....Conclusion: We provide evidence that the inhaled dose of asbestos/fibrous talc from “cosmetic” talc use causes ovarian cancer. The unique combination of the types of asbestiform minerals detected in cancerous tissue and “cosmetic” talc is a fingerprint for exposure to asbestos-containing talc.