PFAS and metabolic syndrome: Some studies have found a positive association between PFAS and MetS (Yang et al. 2018; Chen et al. 2019; Christensen et al. 2019; Yu et al. 2021), but others have shown the opposite association (Lin et al. 2009, Zare Jeddi et al. 2021) or the results did not reach statistical significance (Fisher et al. 2013; Lin et al. 2020; Zare Jeddi et al. 2022).