Sister Study Finds Hazard Ratio Up To 3.34 For Long-Term Talc Users

The NIEHS Sister Study shows that people who use talc for a long time are more than three times more likely to get ovarian cancer, which makes the issue more important for the law and regulators

Friday, June 27, 2025 - The National Institute of Environmental Health Sciences (NIEHS) did longitudinal cohort research and found that women who used talcum powder on their genitals for lengthy periods of time had a hazard ratio of up to 3.34 for getting ovarian cancer. This indicates that people who use it for a long time are more than three times as likely to get sick as people who don't use it. The Sister Study, which followed tens of thousands of women for many years, is one of the most thorough studies on the health dangers of talc to date. A lawyer for people who are suing over talcum powder says that the study's results are a "game changer." He also says that the very high hazard ratio gives strong scientific backing to assertions that manufacturers didn't safeguard consumers even though more and more evidence was coming in. The Sister Study is becoming more and more important in talcum powder cancer litigation as proof that corporate defendants ignored evident and growing safety warnings for years while continuing to aggressively promote their products, especially to women for personal hygiene usage.

The National Institutes of Health (NIH), which is in charge of the NIEHS Sister Study, says that the study design adjusted for a number of factors that could increase the risk of ovarian cancer, including genetics, hormone use, reproductive history, and other possible causes. The results reveal that using talc for a long time causes chronic inflammation that lasts for a long time. Scientists think this may be a direct cause of cancer in ovarian tissue. Talcum powder cancer lawyers say that the strength of these findings should have led to rapid government action years ago, yet manufacturers kept selling talc-based powders without changing warning labels or testing protocols. Experts in public health think that items used on places that absorb a lot of moisture, like the genitals, ought to meet very strict safety criteria, especially since data consistently demonstrates that they raise the risk of cancer. Lawmakers and consumer organizations are now pushing for laws that compel talc-based goods to have cancer warnings on them and that cosmetic companies have to list all of the ingredients in their products. The Sister Study's 3.34 hazard ratio is being used in court as proof that there was serious injury that could have been avoided. Many lawyers think that juries in the future may see the behavior of talc makers in the past as a careless disregard for the safety of consumers. People who work in the industry are worried that this kind of damaging scientific proof could lead to big punitive damage awards, regulatory penalties, and even companies leaving the market as consumer trust continues to drop. The Sister Study's results may have an impact on global talc cases and regulatory oversight for years to come, thanks to more media coverage and more lawsuits.

The NIEHS Sister Study says that long-term talc users had a risk of ovarian cancer that is up to 3.34 times higher than what was thought before. Talcum powder cancer lawyers contend that these results make it hard for manufacturers to defend themselves against charges that they ignored clear safety facts. Researchers at the NIH back up the study's strict methodology and strong conclusions. As more scientists agree on the need for greater safety warnings, transparency standards, and possible market restrictions, regulators and lawmakers are under more and more pressure to act.