The differences in serum thyroid-stimulating hormone levels of patients with thyroid tumors in the areas with different iodine levels in drinking water

Abstract

Objective We investigated serum thyroid-stimulating hormone (TSH) concentrations in patients who had been diagnosed thyroid tumors in areas with different iodine levels in drinking water. We evaluated the significance of serum TSH levels in thyroid tumors. Methods An ecological study of patients from Heze Municipal Hospital, Shanxian Central Hospital and Caoxian People's Hospital was implemented. Variables included age at diagnosis, gender, TSH level, final histology (benign versus cancer), and iodine concentrations in the drinking water. We compared the serum TSH levels of patients with benign and malignant thyroid tumors. The patients were divided into 5 groups based on serum TSH ( 1.50-2.50, > 2.50-5.57, and > 5.57 mU/L), and we analyzed the constituent ratio of patients with thyroid cancer. We analyzed the correlation between serum TSH levels of patients with thyroid cancer and iodine concentrations in the drinking water by the statistical method of Spearman rank correlation. Results Thyroid cancer patients (n= 190) had higher serum TSH levels [2.55 (0.10-20.46) mU/L vs2.24 (0.01-24.90) mU/L, Z=-2.33, P 1.50-2.50, > 2.50-5.57 and > 5.57 mU/L; the constituent ratio of malignant tumor increased with increasing TSH concentration, with respective rates of 21.6% (8/37), 21.2% (39/184), 25.8% (46/178), 27.8% (64/230), and 30.4% (34/112) in the 5 groups, but there was no significant difference (χ2= 4.086, P > 0.05). There was a positive correlation between serum TSH levels of patients and iodine in drinking water (rs= 0.539, P < 0.05). Conclusion Our study has supported an association between preoperative TSH levels and risk of malignant tumors in patients who had been diagnosed thyroid tumors in areas with high water iodine levels. Key words: Drinking water; Iodine; Epidemiology; Thyroid-stimulating hormone; Thyroid tumors