Serum per- and polyfluoroalkyl substances in relation to circulating thyroxine levels and thyroid cancer risk: results from the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial cohort

= 0.092). These associations remained in analyses additionally adjusting for PFAS. No consistent evidence of a positive association with thyroid cancer was observed for other PFAS. In the meta-analysis, PFOA was positively associated with thyroxine (P = 0.006), including after adjustment for PFOS (P = 0.03). Our findings provide evidence in support of effects of some PFAS on thyroxine production, and against PFAS associations with increased thyroid cancer risk. These findings in a low-exposed population have important public health relevance, given their comparability in the distribution of serum PFAS concentrations to that of the general population.