Why Quitting Smoking can cause Hashimoto’s Disease


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Globally, tobacco use is responsible for 6 million deaths each year. In United States alone, more than 16 million people are living with diseases that are caused by exposure to first-hand or second-hand cigarette smoking. On a positive note, the trend of cigarette smoking has markedly reduced in the United States due to vigorous efforts made by both governmental and non-governmental agencies.

Many smoking cessation campaigns are organized by doctors to bring awareness about beneficial health outcomes of quitting smoking, but the conflicting queries and statements regarding smoking cessation make smokers doubtful about their decision. The most controversial question regarding quitting smoking is; why does quitting smoking makes you Hypothyroid?

Smoking and thyroid gland

The disturbing effects of smoking are mainly linked to cyanide, a significant component of cigarette smoke which gets converted into thiocyanate compounds. These compounds can reduce thyroid hormone production by restricting the iodine uptake by gland. Moreover, this compound along with other chemicals can also obstruct the actions of thyroid hormone on our body.

In spite of the negative effects, it has been observed that cigarette smoking has a protective role against some autoimmune and inflammatory disorders.

Quitting smoking can make you hypothyroid

The most common cause of hypothyroidism in the US is Hashimoto’s Disease. Hashimoto’s Disease (or Hashimoto’s Syndrome) is an autoimmune disease in which the body’s own antibodies attack and reduce the thyroid function causing hypothyroidism.

Surprisingly, people who quit smoking are 6 times more likely to develop Hashimoto’s disease. Even more surprisingly, about 85% of the people who developed Hashimoto’s Disease after quitting smoking, would not have develop Hashimoto’s Disease if they had continued to smoke. On the bright side, this increased risk of developing Hashimoto’s Disease after quitting smoking is relatively short lived and after 2 years of quitting smoking there may not be any additional risk.

Why does quitting smoking cause Hashimoto’s Disease?

The possible reasons behind Hashimoto’s disease due to smoking cessation is not clear; but several theories have been proposed:

  • Quitting smoking abruptly reduces the levels of thiocyanate compound in the blood. This also means that iodine uptake also increases suddenly, which can lead to reactionary hypothyroidism (just like suddenly increasing the dietary intake of iodine leads to hypothyroidism).
  • In addition, autoimmune antibodies are less common in smokers, compared with non-smokers. As Hashimoto’s Disease is an autoimmune disorders, the lower levels of antibodies in smokers may prevent Hashimoto’s Disease.
  • Positive effects of smoking on immune system are mainly attributed to an alkaloid compound anatabine. When smokers quit smoking, the source of anatabine is also lost; thereby leading to Hashimoto’s Disease


It is important to keep in mind that cigarette smoking is the number one preventable cause of death. According to latest data released by Centers for Disease Control and Prevention, each year more than 480,000 preventable deaths are attributed to tobacco consumption in the United States. This corresponds to 1,300 deaths per day.

Although, quitting smoking may increase the risk of Hashimoto’s Disease in the short run, once the body resumes its normal biological functions, the risk of developing Hashimoto’s Disease also returns back to normal.

About Sameer Ather, MD, PhD

Sameer Ather MD, PhD is a Cardiologist based out of Birmingham, Alabama and is also the co-founder and CEO of website www.xpertdox.com, which is designed to help patients suffering from rare or serious diseases. His current research focus is to identify heart failure patients who do not benefit from beta-blocker.