The goal of this observational study is to identify the risk factors for post-thyroidectomy hypoparathyroidism in Estonia and to determine whether the magnesium level plays a significant role in the development of hypoparathyroidism. The main questions it aims to answer are:
* How common is post-thyroidectomy hypoparathyroidism in Estonia?
* What are the most significant risk factors for the development of post-thyroidectomy hypoparathyroidism in Estonia?
* Are magnesium levels a risk factor for the development of hypoparathyroidism? Participants will be asked to answer a questionnaire about risk factors. The study collects data on risk factors for hypoparathyroidism following thyroid surgery, including patient questionnaires and comorbidities, pre- and postoperative laboratory tests and surgery-related risk factors.