biostudies-literatureLi ZNational Key Research and Development Program of China563https://www.ebi.ac.uk/biostudies/studies/S-EPMC12225033biostudies-literatureUnknown30(1)Estrogen and thyroid hormone interact extensively in vivo, but the relationship between phytoestrogens and thyroid function and thyroid hormone sensitivity remains unclear. Using 2007-2010 NHANES data of United States, we analysed the association of six urinary phytoestrogens with thyroid function and thyroid hormone sensitivity using a weighted multivariate linear regression model. The final analysis included 2521 euthyroid participants. After weighted multivariable adjustment (excluding dietary patterns and serum iodine levels), urinary phytoestrogen concentrations showed significant sex- and compound-specific associations with both thyroid function indicators and thyroid hormone sensitivity indices. For thyroid function, in males, Equol and Enterodiol showed negative associations with fEuropean journal of medical researchUrinary phytoestrogen levels and reduced thyroid hormone sensitivity: a cross-sectional analysis of NHANES 2007-2010.PMC122250332020YFC2008905Hu FLi ZYao YLu YYu HfalseUrinary phytoestrogen levels and reduced thyroid hormone sensitivity: a cross-sectional analysis of NHANES 2007-2010.Estrogen and thyroid hormone interact extensively in vivo, but the relationship between phytoestrogens and thyroid function and thyroid hormone sensitivity remains unclear. Using 2007-2010 NHANES data of United States, we analysed the association of six urinary phytoestrogens with thyroid function and thyroid hormone sensitivity using a weighted multivariate linear regression model. The final analysis included 2521 euthyroid participants. After weighted multivariable adjustment (excluding dietary patterns and serum iodine levels), urinary phytoestrogen concentrations showed significant sex- and compound-specific associations with both thyroid function indicators and thyroid hormone sensitivity indices. For thyroid function, in males, Equol and Enterodiol showed negative associations with f2025-01-01T00:00:00Z2025 Jul2025-07-28T03:04:19.876Z2025-07-28T03:04:19.876ZS-EPMC122250334060492810.1186/s40001-025-02800-3