In this article:
- How hypothyroidism affects the body
- Long-term consequences of untreated hypothyroidism
- Long-term outcomes of treated hypothyroidism
The thyroid is a powerful organ situated at the nape of the nape. Although small compared to most other organs in the body, the thyroid is considered the metabolic powerhouse. As part of the endocrine system, it is responsible for regulating your metabolism, growth, and development. The thyroid produces thyroid hormones, which travel through the bloodstream to communicate to every cell in your body.
Untreated thyroid disease puts patients at risk for other ailments, such as cardiovascular diseases, osteoporosis, and infertility. However, people who are treated with thyroid hormone replacement medication consistently have an average life expectancy.
How hypothyroidism affects the body
Hypothyroidism is when the body cannot produce enough thyroid hormones—thyroxine (T4) and triiodothyronine (T3)—to support metabolic demands. When your thyroid hormone production drops, your body processes slow down and change, affecting virtually every system in your body.
Common symptoms of hypothyroidism include:
- Changes in the menstrual cycle
- Dry hair and hair loss
- Dry skin
- Elevated cholesterol
- Greater sensitivity to cold
- Hoarse voice
- Joint pain, stiffness, and swelling
- Problems with memory
- Muscle aches and stiffness
- Muscle weakness
- Puffy face
- Slow heart rate
- Swelling of the thyroid gland (goiter)
- Unexplained weight gain or difficulty losing weight
People who have hypothyroidism can develop these symptoms within a matter of days to over several years. It can also start at any point in life, although diagnosis is most common in women during and after menopause. Often these symptoms are confused with other conditions, resulting in a misdiagnosis or missed diagnosis.
If you're experiencing symptoms, consider taking a thyroid blood test to understand how your thyroid is functioning. Many labs only look at thyroid-stimulating hormone (TSH). Still, we believe it's important also to measure free triiodothyronine (fT3), free thyroxine (fT4), and TPO antibodies. These four markers help you understand the big picture of what's happening with your thyroid function and where specifically to make improvements.
What are the long-term consequences of untreated hypothyroidism?
If hypothyroidism is left untreated, it can lead to several health problems, including infertility, congenital disabilities, obesity, joint pain, heart disease, and goiter.
Low thyroid hormone levels may result in irregular menstrual cycle patterns, ovulation problems that lead to abnormal endometrial development, high prolactin levels, or sex hormone imbalances. All of these can affect fertility, making it harder for a woman to conceive.
As such, normal thyroid function is necessary for fertility and healthy pregnancy. You should test your thyroid function if:
- You plan to get pregnant
- Have a history of thyroid problems or irregular periods
- Have miscarried
- Are unable to conceive after one year of unprotected sex
Untreated maternal hypothyroidism can lead to preterm birth, low birth weight, and respiratory distress in the baby. Evidence also shows that thyroid hormones are essential for the normal development of the fetal brain.
Thyroid dysfunction may affect body weight and composition, body temperature, and energy expenditure regardless of physical activity. Clinical evidence suggests that even mild thyroid dysfunction may link to body weight changes and represent a risk factor for obesity. Excess weight can lead to a series of other health complications, including osteoporosis, sleep apnea, diabetes, and heart disease.
Musculoskeletal manifestations often accompany hypothyroidism, ranging from muscle and joint pains to arthritis or disease of muscle tissue. Having joint pain can make it harder to stay active, increasing your risk for weight gain. Furthermore, chronic pain can also lead to depression, which is another symptom of hypothyroidism.
Thyroid hormone significantly affects the cardiovascular system. Both clinical and subclinical thyroid dysfunction associate with an increased risk of coronary heart disease, heart failure, and mortality.
Underactive thyroid increases your risk for heart problems, including:
- Slowed heart rate
- Blood vessel constriction
- Increased blood pressure
- Fluid retention causing swelling
- High cholesterol levels
When thyroid hormones are low, the pituitary gland continually stimulates the thyroid to produce more hormones. This excessive stimulation can result in a large swelling of the thyroid, which eventually creates a bulge in your neck, called a goiter.
Myxedema coma is the extreme manifestation of hypothyroidism. It is an uncommon but potentially life-threatening complication of extremely low thyroid hormone. In this condition, the metabolism slows to the point where it puts a person into a coma. It usually occurs in people who have had untreated hypothyroidism for a long time.
What are the long-term outcomes of treated hypothyroidism?
Hypothyroidism is a treatable health condition. The earlier you start treatment, the less likely you are to experience long-term consequences.
You will likely need to take a thyroid hormone replacement medication for the rest of your life. There are many different ways to treat hypothyroidism, including trying different thyroid medication types and taking combination therapy (like T3 and T4 together).
Once you start medication, it can take some time to find the right dose for you. Within a few months, many people find the optimal dose for managing their symptoms and have stable thyroid hormone levels.
Beyond taking thyroid hormones, you can support your thyroid with nutrition and lifestyle modifications.
Some studies link hypothyroidism to increased longevity
As mentioned, thyroid hormone significantly affects the cardiovascular system. The Rotterdam Study, a population-based, prospective cohort study, aimed to investigate thyroid function association with overall life expectancy and life expectancy with and without cardiovascular disease.
This study, published in the Journal of the American Medical Association, suggests that people with low thyroid function live up to 3.5 years longer overall.
Furthermore, the study suggests that people with low thyroid function may live up to 3.1 years longer without cardiovascular disease than people with high/normal thyroid function. There is some thought that a low-normal thyroid function may cause energy conservation. Other theories indicate there may be a genetic component linked to hypothyroidism that increases longevity.
This research has some limitations to consider. For instance, this study includes predominantly white people older than 45 years, so the findings require confirmation in other populations. Additionally, while the study included TSH and thyroid hormone, thyroxine (T4), it did not have data on triiodothyronine levels (T3).
Heart disease is one of the primary concerns when it comes to life expectancy and thyroid disease. One study identified that both undertreating or overtreating hypothyroidism could increase heart disease risk, which is the leading cause of death in Americans.
A note from Paloma Health
Thyroid patients who consistently take the right dose of thyroid replacement medication can lead healthy lives and may even have increased longevity. However, untreated hypothyroidism can lead to a decreased quality of life and increase your risk for long-term complications like heart disease.
Schedule a consultation with a Paloma Health thyroid doctor to optimize your thyroid function to reclaim your health and improve your quality of life.