Hypothyroidism, also known as underactive thyroid, is a common condition where the thyroid gland does not produce enough thyroid hormone. Thyroid hormone plays an important role in regulating metabolism, growth, development, and many other body functions. When thyroid hormone levels are low, it can cause a variety of symptoms like tiredness, weight gain, feeling cold, and more.
What causes hypothyroidism?
There are a few main causes of hypothyroidism:
- Hashimoto’s thyroiditis – This is an autoimmune disorder where the immune system attacks the thyroid gland, damaging it and reducing hormone production. It is the most common cause of hypothyroidism.
- Thyroid surgery – Removal of part or all of the thyroid gland can lead to hypothyroidism.
- Radiation therapy – Radiation treatment for cancers of the head and neck can affect the thyroid.
- Medications – Some medications like lithium and amiodarone can impact thyroid functioning.
- Congenital hypothyroidism – Some babies are born with an underactive thyroid.
- Iodine deficiency – Lack of sufficient iodine in the diet can lead to hypothyroidism.
- Pituitary disorders – The pituitary gland helps control thyroid hormone production. Pituitary issues can disrupt this.
Does hypothyroidism run in families?
Research has shown that there is often a genetic link or family history associated with hypothyroidism. Some of the key points on hypothyroidism running in families include:
- Having a first-degree relative with autoimmune thyroid disease like Hashimoto’s significantly increases your risk. First-degree relatives include parents, siblings, and children.
- Identical twins have a 55% chance of both developing Hashimoto’s if one twin has it.
- Children with one parent who has Hashimoto’s have a 30% chance of developing it.
- The genes HLA-DR3 and HLA-DR4 are associated with a heightened risk of Hashimoto’s thyroiditis.
- Congenital hypothyroidism resulting from thyroid dysgenesis can cluster in families.
Overall, scientists recognize that genetics and family history definitely play an important role in the likelihood of developing hypothyroidism. There are likely complex interactions between various genes that predispose people to thyroid problems.
What health conditions tend to co-occur with hypothyroidism in families?
There are several other autoimmune and endocrine disorders that tend to commonly occur in family members with hypothyroidism or Hashimoto’s thyroiditis. These include:
- Type 1 diabetes – Individuals with type 1 diabetes are more prone to Hashimoto’s. About 20% of people with type 1 diabetes also have thyroid antibodies.
- Vitiligo – This skin condition causes patchy loss of skin color. It co-occurs in about 8% of people with Hashimoto’s.
- Rheumatoid arthritis – This autoimmune form of arthritis is more common in those with Hashimoto’s.
- Addison’s disease – This adrenal insufficiency has a genetic link with Hashimoto’s.
- Celiac disease – This autoimmune disorder can be seen alongside Hashimoto’s.
- Multiple sclerosis – This neurologic autoimmune disease has an association with Hashimoto’s.
There are also some other thyroid disorders like Graves’ disease (overactive thyroid) and thyroid cancer that can cluster in families alongside hypothyroidism or Hashimoto’s thyroiditis.
Why does hypothyroidism run in families?
There are a few key reasons why hypothyroidism and related autoimmune thyroid disorders tend to run in families:
- Genetics – As mentioned, certain genes are linked to a higher risk of Hashimoto’s thyroiditis. These genes can be passed down in families.
- Shared environment – Family members often share environmental exposures like infections, toxins, or diet that could potentially trigger autoimmunity.
- Learned behavior – Families share habits and behaviors around things like diet, smoking, stress management, etc. that influence health.
While genetics play a very strong role, lifestyle and environmental factors shared within families also contribute to clustering and higher risk of thyroid disorders within families.
How is hypothyroidism diagnosed when it runs in families?
The diagnosis of hypothyroidism generally involves:
- Thyroid function blood tests like TSH, T4, T3 to check hormone levels
- Potential antibody testing for Hashimoto’s – Thyroid peroxidase (TPO) and thyroglobulin (Tg)
- Physical examination of the thyroid
- Assessing for symptoms of hypothyroidism
- Ultrasound of thyroid gland in some cases
The process is the same even when thyroid disease runs in the family. However, doctors will take family history into account when interpreting results. They may have a lower threshold to test antibodies and diagnose Hashimoto’s if hypothyroidism is prominent in family members. The diagnosis may be made earlier or with less pronounced symptoms if hypothyroidism is expected due to family history.
Should family members be screened for hypothyroidism?
If you have several family members with hypothyroidism or thyroid disease, it is reasonable to consider screening thyroid tests. Some recommendations include:
- Test TSH annually starting at age 35, or earlier if symptoms present
- Screen siblings, children and parents of those with Hashimoto’s or autoimmune thyroid disease
- Test for TPO and Tg antibodies to identify autoimmune thyroiditis
- See a doctor promptly if experiencing any potential thyroid symptoms
Early detection and treatment in those predisposed due to family history may help prevent complications and maintain quality of life.
Can hypothyroidism in families be prevented or avoided?
It is difficult to completely prevent hypothyroidism in familial or genetic cases. However, the following measures may help reduce risk of developing thyroid problems:
- Eat a healthy balanced diet with nutrients that support thyroid function like selenium, zinc, iodine, omega-3s, etc.
- Avoid very low calorie diets for prolonged periods
- Manage stress levels with relaxation, mindfulness, etc.
- Optimize sleep habits and get 7-9 hours of quality sleep nightly
- Achieve or maintain a healthy body weight
- Moderate alcohol intake and quit smoking
- Stay physically active with regular exercise most days of the week
- Take thyroid hormone replacement medication if prescribed
Avoiding known thyroid disruptors like certain medications, supplements, or environmental toxins may also lower risk. While hypothyroidism can’t always be prevented, living an overall healthy lifestyle can help reduce susceptibility.
Conclusion
In summary, there is strong evidence that hypothyroidism and Hashimoto’s thyroiditis run in families and have a genetic predisposition. The risk is highest for first-degree relatives of someone with autoimmune thyroid disease. Several other autoimmune conditions also tend to co-occur in family members. The exact genes involved are still being researched but DNA is a major factor, along with some environmental triggers shared by families. Frequent screening and early diagnosis in families with thyroid disease can help identify problems sooner and improve outcomes with treatment. While not always possible to prevent, living an overall healthy lifestyle may help reduce risk of developing thyroid issues, even in high-risk families.