The correlation between thyroid nodules and body composition: a large-scale cross-sectional study from a health screening cohort

Thyroid nodules (TNs) are among the most common thyroid disorders, and identifying modifiable risk factors is important for screening. This study aimed to assess body composition factors related to TNs through a large-scale retrospective analysis, providing valuable insights into potential predictors for TNs. This hospital-based retrospective study included individuals who underwent health screenings between 2022 and June 2025. On the basis of the inclusion and exclusion criteria, 21,011 individuals were included in the analysis. LASSO regression and multivariable logistic regression were applied to identify independent correlates of TNs. In all participants, older age (OR = 1.028, 95% CI: 1.025–1.031, P < 0.001), male sex (OR = 0.539, 95% CI: 0.507–0.573, P < 0.001), and higher systolic blood pressure (OR = 1.008, 95% CI: 1.006–1.010, P < 0.001) were independently associated with TN risk. Among body composition parameters, higher visceral fat area also showed a positive association (OR = 1.002, 95% CI: 1.001–1.003, P < 0.001). In sex-stratified analyses, age and systolic blood pressure remained significant in both sexes, and extracellular water was positively associated with TNs in males (OR = 1.055, 95% CI: 1.033–1.078, P < 0.001) and in females (OR = 1.078, 95% CI: 1.005–1.156, P = 0.035). In addition to sex, age, and systolic blood pressure, visceral fat area is significantly associated with the risk of TNs. When sex differences were considered, extracellular water is significantly correlated with TN risk in both males and females.