Fig. 2
a, b Correlation analysis between age at diagnosis and tumor size or lymph node metastasis (LNM) in patients with papillary thyroid carcinoma (PTC) aged from 18 to 59 years. Age at diagnosis correlated linearly with tumor size and LNM; tumor size and LNM rate decreased with age (R2 = 0.825, P < .0001 for tumor size and 0.932, P < .0001 for LNM). Tumor size was represented by the mean tumor diameter; LNM was expressed as positive rate. c. Adjusted odds ratio (OR) between patient age at diagnosis and LNM in patients with PTC aged from 18 to 59 years. Covariates included age, sex, race, tumor size, extrathyroidal extension (ETE), multifocality, histology, and distant metastases. Adjusted OR was calculated with reference to 18-year-old PTC patients. The vertical whisker bars represent the 95% confidence intervals (CI). d. Adjusted OR between patient age cut-off and LNM in PTC patients aged from 18 to 59 years. Covariates included: sex, race, tumor size, ETE, multifocality, histology, and distant metastases. Age cut-off was also a covariate, and was incrementally stepped from 21 to 57 years in 1-year increments. The vertical axis represents the adjusted OR for the older group, compared to that of the younger group. The vertical whisker bars represent the 95% confidence intervals (CI). Number of observations: A, 38,741; B, 39,751; C and D, 35,753