سیگار و عملکرد تیروئید

هنگامی که بحث مضرات سلامتی سیگار به میان می‌آید، اغلب ما به اثرات سوء آن بر قلب، ریه و پوست فکر می‌کنیم. However, smoking has a negative effect on other organs of the body, such as the thyroid gland, and disrupts its function. Studies show that smoking has a significant effect on thyroid function, occurrence or exacerbation of thyroid diseases, and even thyroid test results. The compounds in cigarettes prevent the effective absorption of iodine by the thyroid gland and have a negative effect on thyroid hormones. Therefore, the risk of developing thyroid disorders and aggravating existing thyroid problems increases. So, for example, it can aggravate the symptoms of hyperthyroidism and hypothyroidism and make the control and treatment of thyroid diseases more difficult. In the following article, we will examine the effects of smoking on the thyroid.

Tobacco smoke contains substances that affect both the function of the thyroid gland and the thyroid gland itself. One of the components of tobacco is cyanide, which turns into the chemical thiocyanate when smoking. Thiocyanate interferes with thyroid function in three key ways:

• It inhibits the absorption of iodine by the thyroid gland and, as a result, reduces the production of thyroid hormones thyroxine (T4) and triiodothyronine (T3).
• By disrupting the synthesis process in the thyroid gland, it directly inhibits hormone production.
• It increases the excretion of iodine from the kidneys and increases the risk of inflammation of the thyroid gland and general symptoms such as fever, nausea and stomach pain.

Nicotine contained in cigarettes partially moderates the inhibitory effects of thiocyanate on the thyroid gland. In fact, nicotine can temporarily stimulate thyroid function and neutralize some of the negative effects of thiocyanate. But this slight adjustment should not be considered as a justification for smoking. The overall harmful effects of smoking, especially the destructive effects of thiocyanate on the thyroid gland and other body organs, are much greater than this temporary stimulation caused by nicotine.

effect Smoking on hypothyroidism

Smoking can directly affect hypothyroidism (hypothyroidism). One of the most important effects of smoking on this condition is the disruption of iodine absorption. Iodine is a vital substance for the production of thyroid hormones, and smoking, having a substance called thiocyanate, disrupts the absorption of iodine by the thyroid gland. This disorder in iodine absorption reduces the production of thyroid hormones and aggravates the symptoms of hypothyroidism.

In addition, smoking can also affect the performance of hypothyroid drugs and reduce their effectiveness. This issue makes hypothyroidism more difficult to control and leads to symptoms of hypothyroidism such as fatigue, weight gain, depression and dry skin. Also, smoking, by affecting the function of the thyroid gland, directly reduces the production of thyroid hormones and aggravates hypothyroidism; Regardless of the cause of hypothyroidism.

effect Smoking on hyperthyroidism

Nonimmune hyperthyroidism occurs due to thyroid nodules, inflammation of the thyroid (thyroiditis) and excessive use of thyroid hormones. In hyperthyroidism, the thyroid gland produces too much hormone, leading to symptoms such as palpitations, tremors, weight loss, and anxiety. Smoking can aggravate these symptoms and increase the risk of serious complications.

Specifically, smoking reduces the effectiveness of hyperthyroid drugs by interfering with their absorption and metabolism. This makes hyperthyroidism more difficult to control and increases the need for drug dosage adjustments. Also, smoking accelerates the growth of thyroid nodules by stimulating inflammation and changing the function of cells; These nodules can produce too much thyroid hormone. Thyroiditis (inflammation of the thyroid gland) is another cause of non-autoimmune hyperthyroidism, which smoking can aggravate this disease by disrupting the body's immune system and causing inflammation. In summary, smoking not only worsens the symptoms of hyperthyroidism; It also makes its treatment more difficult.

Effect Smoking on autoimmune hyperthyroidism and hypothyroidism

Autoimmune thyroid diseases are disorders in which the body's immune system mistakenly attacks the thyroid gland. Grave's disease and Hashimoto's disease are the most common thyroid autoimmune diseases. Continuous inflammation caused by smoking causes the thyroid gland to enlarge and aggravate its inflammation. This condition can cause many problems for patients with Graves' and Hashimoto's. Also, smoking increases the risk of these autoimmune thyroid diseases by stimulating the body's immune system.

Graves' disease (autoimmune hyperthyroidism)

Graves' disease is an autoimmune hyperthyroidism characterized by an enlarged thyroid gland (goiter). Smokers are twice as likely to develop this disease than non-smokers. In other words, smoking significantly increases the risk of developing this disease.

In addition, smoking in people who already have Graves' disease causes the disease to progress more quickly, worsen symptoms (such as palpitations, tremors, weight loss), worsen eye disease (such as bulging eyes), and have a poorer response to thyroid treatments. This means that smoking not only increases the risk of developing Graves' disease; It also makes its treatment more difficult.

Hashimoto's disease (autoimmune hypothyroidism)

The most common cause of hypothyroidism is Hashimoto's disease, which is a chronic disease. The link between smoking and Hashimoto's disease is not as clear as Graves' disease. However, evidence suggests that smoking can weaken thyroid gland function in people with Hashimoto's and cause goiters, especially in people with iodine deficiency. Iodine deficiency itself can lead to goitre, and smoking increases this risk in susceptible individuals.

effect Smoking on thyroid testing

Several factors affect the results of a thyroid test. This blood test measures the level of thyroid stimulating hormone (TSH), triiodothyronine (T3) and thyroxine (T4); These hormones are essential for thyroid health. Some of these factors cause short-term fluctuations in the level of thyroid hormones, which will be resolved by changing the dose of your medication. But the effect of smoking on thyroid test results is long-term and remains even for some time after quitting smoking.

Smoking can cause changes in thyroid hormone levels that can be seen in blood tests. One of the important effects of smoking on the thyroid test is the increase in the level of free triiodothyronine (free T3) in smokers. This hormone is the active form of thyroid hormone, and its increase can indicate overstimulation of the thyroid gland. In contrast, the level of thyroid-stimulating hormone (TSH), which is secreted by the pituitary gland and regulates thyroid function, is lower in smokers. This decrease in TSH could indicate the suppression of the pituitary gland by thyroid hormones that are increased due to the stimulation caused by smoking.

Also, the level of free thyroxine hormone (free T4) is slightly higher in smokers than non-smokers and ex-smokers. This means that smoking can affect the production of all major thyroid hormones. Interestingly, thyroid tests in people who quit smoking are associated with increased TSH levels and decreased T4 levels. These changes indicate the return of thyroid function to a normal state after quitting smoking.

Summary

Smoking has a negative effect on the thyroid gland, its function and related diseases and even the results of the thyroid test. Impairment of iodine absorption, changes in the level of thyroid hormones and increased risk of autoimmune thyroid diseases are among the negative consequences of smoking on thyroid function. These effects can aggravate hypothyroidism and hyperthyroidism and disturb the results of thyroid tests. Quitting smoking is an effective step towards maintaining thyroid health and improving the quality of life of people with thyroid disorders.