Diabetes and thyroid disease can have similar signs and symptoms which means the presence of one should alert a healthcare provide to look out for the other. Dr Angela Murphy expands on this.

Thyroid disease and diabetes are both common conditions and so it’s not unexpected that many people may be diagnosed with both. There are genetic and pathological reasons why the conditions may co-exist. In addition, the presence of one condition may make it difficult to diagnose and control the other. This is the challenge the healthcare professional must tackle.

The thyroid gland

The thyroid is a small, butterfly-shaped gland found in the neck that secretes two hormones: T4 (90%) and T3. Most of T3 is made by conversion of T4 in the tissues where it is to be used; thus, T3 is considered the active hormone.

The production of thyroid hormones is controlled by the pituitary gland in the brain which secretes thyroid stimulating hormone (TSH). This feedback loop ensures that all the levels are in the normal range.

The role of thyroid hormones is to regulate all the functions in the body, including heart rate and blood pressure, gut function, and cognition.

When a disease process alters the thyroid hormone levels, specific conditions occur: hyperthyroidism (over active thyroid function) or hypothyroidism (underactive thyroid function).

Thyroid disease

*Named after the doctors who first described the conditions.   **Viral, environmental toxin.

Autoimmune thyroid disease

Autoimmune disease occurs when circulating antibodies inadvertently attack normal tissue. In the case of autoimmune thyroid disease, different antibodies cause an inflammatory response in the different cells of the thyroid gland. This is called a thyroiditis.  The damage from some antibodies blocks thyroid hormone production causing an underactive thyroid. Other antibody damage results in overproduction of thyroid hormone causing an overactive gland.

Type 1 diabetes

Type 1 diabetes is an autoimmune condition where antibodies attack the insulin producing cells of the pancreas. When considering its association with thyroid disease we must remember:

• Up to 25% of children with Type 1 diabetes develop autoimmune thyroid disease. Adult females with Type 1 diabetes have a two times increased risk of developing hypothyroidism and males with Type 1 diabetes have a four times higher risk. The combination of autoimmune thyroid disease and Type 1 diabetes is part of the Polyglandular syndrome.
• Patients should be screened (with blood tests) for abnormal thyroid function annually.
• All pregnant women should be screened.
• Hypothyroidism causes hypoglycaemia.
• Hyperthyroidism worsens glucose control.

Type 2 diabetes

Type 2 diabetes develops when insulin secretion decreases from the pancreas and at the same time peripheral tissues (liver and muscle) becomes resistant to insulin. Thyroid disease has an impact in patients with Type 2 diabetes and so:

• Screening should start age 45 years or earlier if person is overweight, has had gestational diabetes, has co-morbidities like high cholesterol and hypertension. Screening should be done every three to five years depending on risk.
• Increase glucose monitoring until normal thyroid hormone levels achieved with levothyroxine.
• Adjust diabetes regimen as necessary.

Effect of thyroid hormones on diabetes management

Excess circulating thyroid hormones (T4 and T3) increases blood glucose levels by:

• Increasing absorption of glucose from the gut.
• Increasing the production of glucose in the liver.
• Increasing insulin resistance.

This implies that the diabetes regimen might need to be changed and insulin doses adjusted. It’s worth remembering to check for thyroid disease if a patient is reporting a sudden need to increase insulin doses for no apparent reason.

The medications used to treat diabetes can affect thyroid hormone levels. Metformin has been found to reduce TSH levels whereas pioglitazone increases TSH and decreases T4.

This means that the relevant thyroid medication may need to be adjusted to compensate for this. These medications for both hypothyroidism and hyperthyroidism (Levothyroxine and NeoMercazole respectively) tend to lower blood glucose, both fasting and after meals. This increases the risk for hypoglycaemia, particularly in a patient with relatively good diabetes control. It also implies that there may be an improvement in blood glucose levels such that there is a decrease in the risk of developing Type 2 diabetes in certain people.

Subclinical- hypothyroidism and hyperthyroidism

Both hyperthyroid and hypothyroidism can exist in a subclinical form. This is when the bloods are partially outside of the normal range but not in diagnostic range. Usually there are no symptoms (subclinical) at this point.

Subclinical hypothyroidism is associated with high blood pressure and high cholesterol and so may present increased risk of cardiovascular disease in the patient with diabetes.

Subclinical hyperthyroidism can cause cardiac arrhythmias and bone loss (osteoporosis), especially in older adults. As patients with diabetes already have an increased risk of heart disease and osteoporosis this condition may need to be treated.

Diabetes, thyroid disease and pregnancy

The health of both mother and baby are significantly impacted by diabetes and thyroid disease, either hypo- or hyperthyroidism. There is an increased prevalence of hypothyroidism in women diagnosed with gestational diabetes.

It’s important to screen and diagnosis this timeously to avoid pregnancy complications and a low-birth-weight baby. One quarter of women with Type 1 diabetes are at risk of developing hyperthyroidism in the weeks after giving birth. Again, healthcare providers need to be aware of this risk and look out for signs, symptoms, and blood level changes in these women.

In summary

Diabetes and thyroid disease can have similar symptoms and signs: weight changes, water retention, fatigue. Indeed, there is a concern that one condition can mask the other. This means the presence of one should alert a healthcare provide to look out for the other. There is no consistent advice with respect to screening, but general advice would be:

TYPE 1 DIABETES screen for thyroid disease:

• At diagnosis
• Annually
• Six weeks after giving birth

TYPE 2 DIABETES screen for thyroid disease:

• If an enlarged thyroid (goitre) is found on examination
• If high blood cholesterol levels and high blood pressure
• History of gestational diabetes
• Family history of thyroid disease
• Repeat screening every three to five years depending on risks

THYROID DISEASE screen for diabetes:

• At diagnosis
• Once thyroid function is normal
• In autoimmune thyroid disease consider annually

Overall, we observe that thyroid disease affects glucose metabolism and abnormal glucose metabolism affects the risk of thyroid disease. This is further complicated by overlap of symptoms and how the drugs for each condition interact with each other. It’s important to be aware that there is an increased connection between the two conditions and screen when appropriate. The influence each condition has on the other can make it challenging to manage both.

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Dr Paula Diab describes several treatment fears that stand in the way of well-managed diabetes.

“Nothing in life is to be feared. It is to be understood.” – Marie Curie

Marie Curie is often spoken about in recognition of her pioneering work in radioactivity that allows us to walk into an X-ray department, casually and fearlessly, and view if a bone is broken or if we have pneumonia. She was the first woman to win the coveted Nobel Prize and the first person to ever win it twice in two different scientific fields! She and her husband were also the first married couple to win a Nobel Prize and she became the first woman to become a professor at the University of Paris. And all of this she achieved almost four decades before she was even allowed to vote. She clearly didn’t fear progress or change at all.

How fear plays a role

People with diabetes tend to live in a constant state of fear: What happens if I eat this? Will my blood glucose drop? Is it safe to go for a run? What will my doctor say if s/he sees my results? The list is endless. However, fear is counteractive to any type of progress and if we’re going to conquer diabetes and manage it correctly, we need to be one step ahead and not afraid of progressing.

A few years ago, I saw a young lady who was taking maximum oral therapy. She had been a patient of mine for a few years and we had developed a rapport between us. Her HbA1c had increased over time and at every visit, I had gradually started introducing the topic of insulin. My persuasions were met with absolute fear and obstinate rejection. So much so that I was surprised that she continued to return every six months as I thought that she would seek care elsewhere. Her fears to commencing insulin were rooted in her contextual story that included relatives passing away from complications of diabetes and the perception that she had failed in her diabetes management if I was suggesting that she needed insulin.

Fast forward to a few months ago when a happy, content and well-managed patient walked briskly into my office laughing, saying she can’t believe how silly she must have look a few years ago when she was crying and refusing insulin. This patient now injects twice a day with no problems, knows how to adjust doses depending on her activity and meals, and feels so much healthier. Her HbA1c has improved, the mild retinopathy she had has resolved, she has lost weight and now manages her diabetes instead of her diabetes managing her.

Changing treatment fears

What changed? She no longer fears insulin but understands it; that insulin comes in the form of an injection just like oral medications come in the form of tablets. That is how insulins are manufactured. She understands that insulin isn’t the end of the road in diabetes and that many new research papers are starting to advocate the benefit of early onset, very low dose insulin in some cases. She also understands that timely intervention can resolve some complications and prevent others. Now, she understands that there is no such thing as failure in diabetes but rather a different treatment path that needs to be followed.

Diabetes isn’t a disease that can be treated with a bi-annual, 15-minute check-up and six-monthly script. There are so many daily influences on how glucose levels react, and we need to understand how these factors relate to manage diabetes correctly. When you fear insulin initiation or any other aspect of diabetes management, you’re placing unnecessary obstacles in your way that will hinder progress. Hopefully, in understanding these obstacles, they can be overcome.

Fear of insulin

This is probably the most common fear that people with diabetes have. It’s a misconception that only children with Type 1 diabetes will need insulin. If you live long enough with diabetes, you’ll eventually need insulin.

Insulin isn’t dangerous if used correctly and shouldn’t be painful to inject. Using insulin doesn’t have to place restrictions on your lifestyle. Make sure that your healthcare provider shows you how to inject correctly and change the needles. Very often, preventing a painful injection can be as simple as using the correct technique and changing needles regularly.

If given in the correct dose and monitored correctly, insulin isn’t dangerous. It reduces your blood glucose levels but that is what it’s meant to do.

You need to monitor your glucose levels and understand what will cause a precipitous drop and how to avoid those situations. This requires a good doctor-patient relationship, specialised diabetes education and regular glucose testing. Knowing how to manage a lower glucose level and what to do in the case of an emergency are just as important as knowing how to inject the insulin.

Many people also have the idea that to inject, you have to leave the room and do so in private without anyone knowing. Again, this doesn’t have to be the case.

In addition, many newer regimens involve insulin given only at night or an injection given in the morning to control glucose levels throughout the entire day. It may not be necessary to take insulin before each meal when you first start insulin. It can be as simple as when you brush your teeth at night, you take your injection. These are just a few examples of the fears surrounding insulin usage, all of which can be managed through understanding more about the medication and seeking professional advice.

Fear of disease progression

Diabetes is a chronic, progressive disease which means that from the day that you’re diagnosed with diabetes, it will naturally become more of a threat to your general health. In fact, recent evidence shows that by the time you’re diagnosed with Type 2 diabetes, you’ll already have lost 50% of your beta cell functioning in the pancreas and that this loss of function will decline throughout the course of the disease.

This is a good reason to always be one step ahead of your diabetes. Don’t wait until your vision deteriorates before you seek help, get your eyes checked regularly even if you think you can see fine. Don’t wait until wounds start healing poorly or you have cardiac symptoms before you seek specialised care. From the very outset, your healthcare team should be looking for these complications and advising on how they can be prevented.

The disease will progress. The medication that you took two years ago may no longer be effective. Complications will occur. But the trick is to manage these complications, mitigate the risk factors and regularly seek specialised care to help you understand where the risks are and how they can be managed.

Fear of hypos

In a previous article, I spoke about the fears of hypoglycaemia and how to manage them. Hypoglycaemia is a very real threat and is the cause of significant morbidity and mortality every year. However, if you know how to predict and treat hypos and have the correct support in place, this risk can be managed.

Newer insulins and medications have a far lower hypo risk than previous preparations did and are generally safer to use. However, being educated and aware of hypoglycaemia is still the best solution.

Fear of seeing the doctor

Often, I joke with my patients that I don’t have a police hat nor a big stick. As healthcare providers, our role isn’t to chastise patients who don’t behave or to point out all the negative aspects of their management. Our role is rather to guide and educate. Obviously, we do have to identify the short-comings to know where to make changes but thereafter, the solution to fixing the problem is to understand it and give guidance on how to change.

Don’t delay in seeking healthcare and seeking the best type of care you can access because you’re afraid of what the doctor will think or say. The patients who cause us distress are those who are unstable, and we don’t understand, not the ones who need and ask for our help.

Get rid of treatment fears by understanding

The only time diabetes needs to be feared is when left unmanaged as it has complications that can be life-threatening. It requires careful lifestyle management and daily attention to manage it correctly. But it shouldn’t be feared, rather understood.

If you have never seen a diabetes educator, ask your doctor or pharmacist who you can contact in your area to help you understand this curious disease. Seek to understand and embrace your diabetes. In the end, a diabetes lifestyle is a healthy lifestyle that everyone should be following.

Being afraid of diabetes is going to be an obstacle to managing it well. Seek to understand more about the disease, its complications and how it can be managed, and you’ll find yourself walking briskly into your doctor’s office laughing at how unfounded your initial fears really were.  

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