1. The influence of lifestyle (obesity, type 2 diabetes mellitus).
2. Autoimmune processes (autoimmune thyroiditis, adrenal insufficiency).
3. Genetic disorders (Klinefelter syndrome, Prader-Willi syndrome).
4. The consequences of surgery (for example, thyroidectomy), radiological treatment (irradiation of the pituitary gland) or as a side effect of drugs (for example, prolonged use of glucocorticosteroids).
5. Exposure to toxic substances, radiation.