Invited Perspective: Challenges in Evaluating the Effect of Per- and Polyfluoroalkyl Substance Mixtures on Polycystic Ovarian Syndrome

The health effects of chemical mixtures are an imperative research priority for environmental epidemiology, but there are numerous challenges in evaluating and interpreting the available evidence for these effects.New work by Zhan et al. 1 published in this issue addresses some of the key challenges related both to the specific outcome of interest and to disentangling relationships for any outcome with complex mixtures.Zhan et al. use both novel and traditional statistical models to estimate both individual and joint associations between 23 different per-and polyfluoroalkyl substances (PFAS) and risk of polycystic ovarian syndrome (PCOS)-a departure from most past human health studies, which examined coexposures to PFAS primarily as confounders or not at all.