In recent years, more and more patients with thyroid nodules have been found in health checkups and clinical clinics, but there is no unified authoritative opinion on the management of thyroid nodules. A significant proportion of thyroid nodules found on physical examination are Hashimoto’s thyroiditis, in addition to nodular goiter, and of course a small proportion are thyroid cancer, which causes alarm and fear. In our real life, the attention to the thyroid gland is far from enough. The previous health checkups of various units did not include the thyroid gland, so the detection rate of thyroid disease was relatively low, but now the checkup centers have prompted the addition of thyroid ultrasound and thyroid function to the routine health checkup program. Among thyroid diseases, hyperthyroidism or hypothyroidism often have obvious symptoms and are easily noticed, but thyroid nodules and early thyroid cancer are often asymptomatic and may be overlooked. 2012 Guidelines for the diagnosis and treatment of thyroid nodules and differentiated thyroid cancer show that the prevalence of thyroid nodules obtained by palpation is 3% to 7%, while the prevalence of thyroid nodules obtained by high-resolution ultrasound is 3%. The prevalence of thyroid nodules is 20% to 76%, and the prevalence of thyroid cancer among thyroid nodules is 5% to 15%, so it deserves attention and attention. The thyroid gland is the largest endocrine organ in the human body, and it is the place where thyroid hormones are synthesized, stored and secreted. Thyroid hormones mainly regulate the body’s metabolism, and fetuses, young children and adolescents need sufficient amounts of thyroid hormones for human growth and development. Therefore, even if there is no obvious discomfort, physical examination of the thyroid gland is very necessary, especially physical examination by a thyroid specialist and high-resolution ultrasound examination are of great significance in assessing thyroid nodules and identifying benign and malignant, and they contribute more to early detection and diagnosis of thyroid cancer. Risk factors for thyroid cancer are more noteworthy: (1) history of radiation exposure to the head and neck during childhood or exposure to radioactive dust; (2) previous or family history of differentiated thyroid cancer, medullary thyroid cancer or multiple endocrine adenomatosis type 2, familial polyposis, certain thyroid cancer syndromes; (3) history of systemic radiation therapy; (4) solitary thyroid nodules in men; (5) nodules with rapid growth, irregular shape (6) persistent hoarseness, dysphonia, and vocal cord lesion can be excluded; (7) difficulty in swallowing or breathing, and pathological enlargement of lymph nodes in the neck. If you have any of these conditions, you don’t have to be shy about it, and you certainly don’t have to be overly alarmed. It’s wise to see a thyroid specialist at a regular hospital. What is the reason for so many thyroid diseases, especially Hashimoto’s thyroiditis and thyroid cancer, the incidence of which is increasing year by year? It can be said that the iodine in our life has an inescapable responsibility. As we know, iodine is an essential trace element for the human body and a raw material for the synthesis of thyroid hormones. Therefore, it is important to promote scientific iodine supplementation. Iodine, as a raw material for synthesizing goitre, can lead to goiter, which can be manifested as diffuse goiter and nodular goiter, and in severe cases, hypothyroidism, while excess iodine can also lead to goiter, almost mainly diffuse goiter. Iodine intake is the most beneficial. High iodine intake can trigger the development of autoimmune thyroid diseases such as Graves’ disease (primary hyperthyroidism) and Hashimoto’s disease (autoimmune thyroiditis, often accompanied by hypothyroidism). The incidence of both diseases is significantly higher in coastal areas with high iodine, and thyroid nodules can be seen in both high and low iodine areas, only slightly more in high iodine areas than in low iodine areas. How to treat the relationship between iodine and thyroid disease? First of all, we should treat the advantages and disadvantages of iodized salt. Although excessive iodine can lead to hyperthyroidism, hypothyroidism and thyroid nodules, after the popularization of iodized salt, the incidence of endemic goiter has been significantly reduced and the intelligence and physical quality of the population have been significantly improved. This is an indisputable fact, so universal iodized salt is still a long-term prevention and treatment strategy in China. In the past, people mistakenly referred to thyroid disease as “thick neck disease” and ate a lot of kelp and other high iodine foods for both hyperthyroidism and hypothyroidism, resulting in excessive iodine intake. Recently, more people have learned that excessive iodine can also lead to thyroid disease, especially in coastal areas with high iodine levels, so many people are afraid of iodine and have gone to the other extreme – avoiding iodine diet. Iodine supplementation in life needs to be individualized, and both high iodine diet and low iodine diet should not be applied across the board, but should vary from place to place and from person to person. Even if people in the same region have different dietary habits, there are also iodine excesses and iodine deficiencies, and since the iodine content varies greatly from one environment to another, a low iodine diet cannot be imposed. The requirements of low iodine diet are also different for different thyroid diseases. Patients with hyperthyroidism should be strictly required to have low iodine diet, while chronic thyroiditis can easily lead to hypothyroidism. It is necessary to prevent the occurrence of thyroid disease in relatives. If a pregnant or lactating woman has thyroid disease, she should eat a diet high in iodine to meet the developmental needs of the fetus or infant. A low iodine diet at this time may lead to goiter in fetuses and infants, and may even affect the development of IQ and height of young children. In conclusion, to prevent and treat thyroid diseases, iodine supplementation should avoid blindness, extremes and one-size-fits-all, and should be individualized according to the location, person, disease and time, so as to care for the thyroid gland and promote scientific iodine supplementation!