Endocrine Abstracts

Background: We investigated the frequency for diagnosis of Hashimoto’s thyroiditis (HT) in obstructive sleep apnea (OSA) patients, based on rising interest in potential links of OSA’s pathogenesis with impaired auto-immune mechanisms.

Design and methods: Polysomnography was performed to 245 euthyroid eligible subjects consecutively. Study population divided according to apnea-hypopnea index (AHI) as control (n=59, AHI<5), mild OSA (n=59, 5≤AHI<15), moderate OSA (n=61, 15≤AHI<30) and severe OSA (n=66, AHI≥30) groups. All subjects undergone thyroid ultrasound; serum anti-thyroglobulin (anti-TG) and anti-thyroid peroxidase (Anti-TPO) levels were measured for diagnosis of HT.

Results: Diagnosis of HT was significantly lower in control subjects (32%) compared to severe OSA patients (51%) (P=0.02). Among OSA patients the HT frequency was %42 and %46 for mild and moderate groups respectively (P=0.05). HT was detected in 62% of females, 29% of males and 43% of overall study population (P<0.001). While 73.3% of severe female OSA patients were found to have HT, the ratio was %18.7 in male control subjects (P<0.001). OSA patients had the highest antibody levels compared to controls; as 1000 U/ml versus 400 U/ml for Anti-TG, and 4490 IU/ml versus 650 IU/ml for Anti-TPO respectively (P<0.001). There was no significant correlation between thyroid volume and severity of OSA but isthmus thickness was significantly correlated to AHI (P<0.01, r=0.22).

Conclusions: OSA patients were found to have higher HT prevalence parallel to severity, especially among women. These results may lead to further investigations on potential casual relation between OSA and auto-immune thyroid diseases, besides may lead to development of screening schemas for OSA patients for early diagnosis of HT before development of hypothyroidism, which are clinically overlapping.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector