Abstract: Objective　To analyze the situation of parathyroid adenoma (PTA) with thyroid disease, and discuss the relationship between the size of PTA and the function of parathyroid and thyroid. Methods One hundred patients with PTA admitted to the Affiliated Hospital of North China University of Technology were selected in this study. Patients were divided into two groups according to whether they were combined with thyroid diseases， including patients with thyroid disease group (n=55) and those without thyroid disease group (n=45). The clinical data of the patients were collected, and the correlation between preoperative indexes: age, course of the disease, alkaline phosphatase (ALP), corrected serum calcium, phosphorus, creatinine, total triiodothyronine (TT3), total thyroxine (TT4), free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), parathyroid hormone (PTH) and the size of PTA were analyzed. Logistic regression was used to analyze the risk factors of large adenoma, and receiver operating characteristic (ROC) curve was drawn to analyze the clinical value of preoperative indicators in predicting the larger adenoma. Results　Compared with patients without thyroid disease, a shorter adenoma course was found in the patients with thyroid disease (P＜0.05). There were positive correlations between the size of PTA and corrected serum calcium, PTH, serum creatinine, and course of disease. There was a negative correlation between the size of PTA and FT4 (P＜0.01). Preoperative PTH was positively correlated with corrected blood calcium, ALP, creatinine levels and disease course, and negatively correlated with blood phosphorus, TT4 and FT4 (P＜0.01). Preoperative TT4 level was negatively correlated with corrected blood calcium, ALP, creatinine levels and disease course, and positively correlated with blood phosphorus and FT4 levels (P＜0.05). Preoperative FT4 level was negatively correlated with adjusted blood calcium, FT3 level and disease course (P＜0.01). Logistic regression analysis found that preoperative PTH and disease course were risk factors for predicting large adenomas. The ROC curve suggested that the combined detection of PTH and disease course before surgery can further improve the sensitivity of predicting large adenomas. Conclusion　The size of PTA is positively correlated with preoperative PTH level. The combined consideration of preoperative PTH and course of disease could be a predictor of larger PTA, suggesting that hyperparathyroidism may inhibit thyroid function.

Key words: parathyroid neoplasms, adenoma, hyperparathyroidism, primary, hypothyroidism, parathyroid adenoma