Endocrine Abstracts

Objectives: Hearing impairment is mainly described in congenital hypothyroidism and iodine deficiency in children. Hearing impairment has a major impact on behavior, educational attainment, social status and quality of life. In connection with thyroid disease, little attention is paid to hearing impairment. The incidence of hearing impairment in congenital hypothyroidism reaches 35-50%. The pathogenesis, incidence and severity of hearing impairment is even less known in acquired hypothyroidism with a reported incidence of 25%. The aim of our study was to evaluate hearing in acquired hypothyroidism.

Methods: 30 patients with untreated and newly diagnosed peripheral hypothyroidism (H) and a control group of 30 healthy probands (C) were enrolled into the study. Biochemical examinations were performed including the determination of median iodine urine concentration (IUC) μg/l established by 3 morning urine samples. The hearing examination included subjective complaint assessment, otomicroscopy, tympanometry, transitory otoacoustic emission (TOAE), tone and verbal audiometry, and brainstem auditory evoked potential (BERA) examinations. Mann-Whitney U test, Fisher’s Exact test and multivariate regression (a method of orthogonal projections to latent structure, OPLS) were used for statistical analysis.

Results: The H and C groups were significantly different in thyroid hormones levels (medians with 95% CI) TSH mU/l 13.3 (8.1, 19.3) vs. 1.97 (1.21, 2.25) P = 0, fT4 pmol/l 10.4 (9.51, 11.1) vs. 15 (13.8, 16.7) P = 0, anti-TPO IU/ml 335 (164, 520) vs. 28 (4.78, 31) P < 0.01, and thyroid volume (mL) 11.9 (10, 13.2) vs. 9.38 (8.6, 10.5) P = 0.019. The H and C groups were not different in age 39 (34, 43) vs. 41 (36,44) P = 0.767, BMI 25.6 (24,28.3) vs. 23 (21.6, 23,9) P = 0.080, and IUC 142 (113, 159) vs. 123 (101, 157) P = 0.814. The hear examinations as otomicroscopy (P = 1), tympanometry (P = 1), TOAE (P = 1), audiometry (P= 0.179), and BERA (P = 0.505) were not different between H and C groups.

Conclusions: We did not observe any hear impairment in patients with acquired hypothyroidism. We have to conclude that our study did not show any associations between hear impairment and severity of hypothyroidism or iodine status.