Thyroid nodules can be caused by iodine deficiency, excessive iodine intake, genetics or emotional factors. 1. Iodine deficiency: Iodine deficiency in life may affect the normal physiological function of the thyroid gland, in order to increase iodine intake, secretion of thyroxine, will make the thyroid tissue cells proliferation, which may lead to thyroid nodules. 2. Excessive iodine intake: Iodine plays a crucial role in thyroid disease, too much or too little iodine can lead to thyroid disease, and excessive iodine intake will also stimulate the thyroid gland, which will lead to the emergence of thyroid nodules in the long term. 3. Heredity: Thyroid disease has a certain hereditary tendency. When someone in the family suffers from this disease, the chance of their children suffering from this disease will be relatively higher. 4. Emotional factors: If your mood is often irritable or depressed, it will easily affect your immunity and resistance. If the mood can not be regulated for a long time, the immune system will have problems, and nodules will appear. Once thyroid nodules are found, it is important to consult a doctor in a timely manner and follow the doctor’s instructions for examination and treatment, so as not to delay the condition.