Epidemiology of talc exposure and ovarian cancer: A critical assessment

Epidemiologic reasoning is based on a progression of scientific studies that begins with a hypothesis and proceeds with hypothesis testing. Subsequently it is necessary to test the validity of observed statistical associations by excluding possible alternative explanations. In the epidemiology of ovarian cancer, there have been several case-control studies that have consistently shown small but increased risks in women using cosmetic talcum powder. These statistical associations have raised concerns that there may be a cause-effect relationship between perineal exposure to talc and ovarian cancer. Currently, such concerns cannot be supported because the validity of these findings has not been evaluated. This paper discusses why the results from all case-control studies could have arisen from inaccuracies in exposure ascertainment, bias, or confounding.