Study on the incidence and etiology of subclinical thyroid function disorders

Objective: To study the incidence and etiology of subclinical thyroid function disorders in 12592 subjects tested. Methods: The etiology of 874 patients with abnormal serum TSH (with IRMA) found in the tested 12592 patients, whose serum T3, T4, FT3 , FT4, TSH, TGA and TMA were also detected with RIA was analyzed. Results: 874 of 12592 patients had abnormal TSH levels (6.94%). Among them, TSH was elevated in 397 patients (3.15%) and decreased in 477 patients (3.79%). Most of them were associated with obvious related thyroid or other thronic diseases such as hyperthyroidism after therapy, thyroxine replacement treatment of hypothyroidism and other thyroid diseases (thyroiditis, diffuse nontoxic goiter). In the remaining apparently disease-free 143 subjects, there were with subclinical hypothyroidism and 34 (3.89% of 874) with subclinical hyperthyroidism. Also among the 874 patients, 30.78% (n=269) patients had elevated TGA and TMA[16.82% (n=147) had elevated TSH and TGA, TMA simultaneously, 13.96% (n=122) had decreased TSH and elevated TGA and TMA simultaneously]. In the 874 patients, 256 (29.29%) were older than 60. Conclusion: Elderly people has higher incidence of subclinical thyroid function disorders. We should pay more attention to the detection of this condition, especially in elderly patients. (authors)