Thyroid diseases are among the most common in the general population. Women are particularly exposed to the risk of developing thyroid dysfunction, which is particularly important because of the possible impact on fertility. Scientific societies and the world of research have often questioned whether adult screening for thyroid diseases should be carried out in the absence of clinical symptoms. In fact, who should undergo a health check to monitor the health of their “butterfly” gland? We asked Professor Andrea Lania, Professor of Endocrinology at Humanitas University and Head of the Endocrinology Operating Unit at Humanitas.
Because of the role of the thyroid in the endocrine system, its dysfunctions can compromise the quality of life of the people who are affected. The gland, situated a little lower than the Adam’s apple, produces thyroid hormones that regulate many metabolic processes in the body. Therefore, in the presence of alterations in hormone secretion by the thyroid gland, symptoms can be varied and affect different functions.
Hyperthyroidism, for example, with an acceleration of thyroid function and an increase in hormone production, will be accompanied by weight loss, heart rhythm acceleration and insomnia. Conversely, hypothyroidism, a condition characterized by a reduction in levels of thyroid hormone circulating in the blood, will be accompanied by apathy and drowsiness, hair loss, constipation, dry skin and hoarseness.
These symptoms are not always present. Hypothyroidism and hyperthyroidism may be present in a subclinical form. Subclinical hypothyroidism is defined as a condition in which, in the absence of symptoms, levels of thyroid stimulating hormone (TSH) exceed a certain threshold; while the level of thyroxine, thyroid hormone, is normal. Similarly, subclinical hyperthyroidism has lower levels of TSH together with normal thyroid thyroxine and triiodothyronine hormones.
Categories most at risk
According to the U. S. Preventive Services Task Force, a screening in the general population is not recommended. Evidence to support this practice among adults who are asymptomatic and not pregnant is inadequate. It is not yet sufficiently clear whether screening can be combined with an improvement in quality of life, cardiovascular health and individual well being.
Pregnant women, on the other hand, represent a population to be monitored more closely. This is because pregnancy has a significant impact on thyroid function: it increases the size of the thyroid gland and the secretion of hormones in the blood. Untreated dysfunction poses serious health risks to women and fetuses. In pregnant women, therefore, the function of the gland will have to be evaluated with care, in particular it will be possible to carry out targeted screening in women who are most at risk: those with family history of thyroid diseases, those with autoimmune diseases and those already affected by thyroid dysfunction in the past.
Another category to be monitored consists of older people over 65 years of age. In these individuals the function of the thyroid changes, its ability to assimilate iodine, the essential mineral for the formation of hormones, decreases, and hypothyroidism can be associated with metabolic and even cardiovascular disorders. Furthermore, its symptoms are often non-specific and do not immediately give rise to suspicion of gland dysfunction. In addition, the prevalence of less severe forms of hyperthyroidism among elderly people increases compared to the general population, in particular associated with the presence of thyroid nodules.