What is the link between diabetes and thyroid problems?

People living with diabetes are more likely to develop thyroid problems. Read on to find out more about diabetes and thyroid dysfunction.

January, 2021


Diabetes does not cause thyroid problems. However, people living with diabetes are more likely to develop hyperthyroidism or hypothyroidism than the general population.

It is important to note that there are two types of thyroid disorder: hypothyroidism (where the body doesn’t produce enough thyroid hormones) and hyperthyroidism (where it produces too much).

People living with diabetes, particularly those with Type 1 diabetes, experience thyroid problems more commonly than those without diabetes. The body’s cells within those living with diabetes can attack the thyroid similarly to how the insulin-producing cells in the pancreas are destroyed.

The body doesn’t produce sufficient thyroid hormones more commonly in those people living with Type 1 diabetes, but it is unclear why those with Type 2 diabetes also develop thyroid problems.

Just like diabetes, there is no cure for thyroid dysfunction, but people can manage it with medication and lifestyle changes.

How are diabetes and thyroid dysfunction connected?

The thyroid is a butterfly-shaped gland in the lower neck, just above the collarbone. It releases the thyroid hormone, which the body needs to convert food and drink into energy. Experts call this process metabolism.

About 6% of the general population have a thyroid disorder. In people with diabetes mellitus, that figure is around 10%. Both conditions affect the hormones or the endocrine system.

People with Type 1 diabetes are more likely to develop thyroid dysfunction because they are both autoimmune conditions. That means problems with the immune system cause them both.

The connection between thyroid dysfunction and Type 2 diabetes is less clear. Scientists are currently working on finding out more.

Are there different types of thyroid dysfunction?

There are two main types of thyroid dysfunction: hyperthyroidism and hypothyroidism.

Hyperthyroidism, or overactive thyroid, means the gland makes too much thyroid hormone. When this happens, the person’s metabolism runs too fast. Symptoms are different for everyone, but they might include:

  • pounding heart
  • fast pulse
  • sweating more than usual
  • losing weight despite eating the same amount or more
  • shortness of breath during exercise
  • diarrhoea
  • weakness in the muscles
  • muscle tremors
  • difficulty concentrating
  • menstrual cycle changes
  • thick skin on the knees, elbows, and shins

Hypothyroidism, or underactive thyroid, means the gland does not make enough thyroid hormone. This slows the metabolism and other bodily processes down. Some of the typical symptoms might include:

  • fatigue, or feeling extremely tired
  • feeling sluggish
  • feeling depressed
  • feeling cold even when others do not
  • constipation
  • unexplained weight gain
  • low blood pressure
  • a slow pulse

How can thyroid dysfunction affect diabetes?

According to the American Diabetes Association, thyroid dysfunction can impact on someone’s ability to manage their diabetes.

In hyperthyroidism, medicines are metabolised, or go through the body, quicker. That means blood glucose levels might rise quicker than people expect them to.

It can be difficult to tell the difference between hyperthyroidism and hypoglycaemia, or low blood glucose levels. People experiencing tremors or sweating often blame the symptoms on low blood sugar. They might then eat more food to compensate, causing their blood sugar to rise. That is why it is important to check blood glucose levels before acting.

Hyperthyroidism and diabetes both increase the chances of someone developing cardiovascular disease. It means that if someone has both conditions, they are at a higher risk than people who have just one of them.

When hypothyroidism slows the metabolism, the person’s blood glucose level may drop. This is because their diabetes medicine is not passing through their body as quickly as usual. Simply, it stays active in the blood for longer.

The condition causes changes in the blood, including higher levels of low-density lipoprotein (LDL), or “bad cholesterol”. This can increase the likelihood of heart disease and stroke.

How is thyroid dysfunction diagnosed and treated?

Some of the symptoms of thyroid dysfunction and diabetes are similar. Both hyperthyroidism and diabetes can cause unexplained weight loss and fatigue, for example. This can make diagnosis tricky.

Anyone who has diabetes and suspects they may have thyroid dysfunction should speak to their healthcare team. Doctors will usually recommend a blood test that looks at the level of thyroid hormones. The test is quick and easy and will help doctors make sure people get the treatment they need.

People with diabetes and thyroid dysfunction will usually need to work with their healthcare team to adjust their diabetes medication. Those with hypothyroidism, for example, tend to need lower doses of insulin because their body’s take longer to process it.

The most common treatment for hypothyroidism is a medication that experts call levothyroxine. It is a pill that people usually take once a day. Their healthcare team will then carry out regular blood tests to check the drug is working.

It can take several months for the treatment to have an effect. Most people will need to take the medicine for the rest of their lives.

Doctors might recommend one of a variety of treatments for hyperthyroidism. Medicines like methimazole and propylthiouracil can help to control the amount of thyroid hormone the body makes. They tend to take between one and two months to work.

Other options include radioactive iodine therapy. This is a type of radiotherapy that destroys cells in the thyroid gland, stopping it from making too many thyroid hormones. Most people only need one treatment, but it might take a few weeks or months to work.

What about exercise?

Staying active is important in both diabetes and thyroid problems. It reduces body fat, lowers blood pressure, and decreases “bad” cholesterol (LDL) in the blood. This will cut the chances of someone developing long-term complications, like stroke and cardiovascular disease.

However, lots of people with thyroid problems feel very tired, have muscle aches, and feel low. This can make it hard to exercise. But it is worth remembering that the more someone exercises, the more energy they will have in general. Physical activity also releases endorphins that make people feel good.

The British Thyroid Foundation offers the following tips for getting started and feeling the benefits of staying active:

  • speak to your healthcare team: your diabetes team will be able to give you advice on exercises that will suit you, your health conditions, and your medication.
  • pace yourself: try starting small. Even going for regular walks will start to increase your strength and fitness. Aim to build up to 30 minutes of physical activity, five times a week.
  • think about activity, rather than exercise: taking the stairs instead of the lift or doing some gardening both count as physical activity, for example.
  • motivate yourself: try a step counter or a fitness tracking app to log your activity and challenge yourself.
  • find something you enjoy doing: you are much more likely to carry on exercising if you are doing something fun. Try different things – dancing, cycling, or swimming, for example – to find out what works for you.

Remember, there is no one best exercise for thyroid problems or for diabetes. The best way to stay active will depend on the person, their lifestyle, and what they enjoy doing.