Hypothyroidism (underactive thyroid) is when the thyroid gland doesn't create enough thyroid hormones to meet your body's metabolic needs. The thyroid gland is a small, butterfly-shaped gland in the front of your neck that produces thyroid hormones that control the way your body uses energy. Thyroid hormones affect essentially every organ in the body. Your body's functions slow down and change with too low thyroid hormone levels.
In the United States, hypothyroidism is most commonly caused by Hashimoto's disease. This autoimmune condition causes inflammation of the thyroid gland. Other causes can include congenital hypothyroidism, surgical removal of all or part of the thyroid gland, radiation treatment, some medicines, or an iodine deficiency.
How many people have hypothyroidism?
If you go online to search for information about hypothyroidism, one thing is clear. No one agrees on the numbers! How many people are hypothyroid? You'll see estimates ranging from 13 million Americans up to 30 percent of Americans—more than 100 million people! What's the reality?
Researchers at the American Thyroid Association did a retrospective study, attempting to answer that very question. They started with statistics from 1988 to 1994, which estimated that 4.6% of the population had hypothyroidism.
The researchers looked at claims data for more than 67 million people between 2012 and 2018.
The data showed:
- Around 7 million (10.5%) had claims indicative of hypothyroidism.
- Based on a yearly assessment, the prevalence grew from 9.5% in 2012 to 11.5% in 2018
- Around 81% of patients received treatment for hypothyroidism, and the rate of untreated patients went from 12.7% to 15.4%
According to the Census Bureau, in 2020, there were 258.3 million adults aged 18 years or older in the United States. Using the study's estimates, an estimated 29.7 million Americans—at a minimum—are hypothyroid.
How many hypothyroid patients are left untreated?
We can also estimate that 4.6 million Americans with hypothyroidism are not being treated for the condition.
Hypothyroidism can lead to complications when left untreated, including congenital disabilities, infertility, elevated cholesterol, or mental health problems. Rarely, untreated hypothyroidism can cause severe heart failure or a myxedema coma.
To note: there's a significant gap in this study's methods and findings. The study looked only at data from patients with medical insurance, excluding the 29.6 million people—8 percent of the population—that the Census Bureau estimated were uninsured in 2019. That would suggest that an estimated 3.4 million more Americans are hypothyroid, bringing the total hypothyroid population to 34.1 million.
The study also does not show how many people complained of potential thyroid symptoms or requested thyroid testing but was refused tests by their practitioners. Unfortunately, this situation frequently occurs, even in patients with medical insurance. So, there's no doubt that this study missed some thyroid patients who never had testing and remain undiagnosed with hypothyroidism.
Common symptoms of hypothyroidism include:
- Cold intolerance
- Dry skin
- Weight gain or difficulty with weight loss
- Puffy face
- Muscle weakness
- Elevated blood cholesterol level
- Muscle pain, tenderness, and stiffness
- Joint pain, stiffness, or swelling
- Heavy or irregular menstrual periods
- Thinning hair or hair loss
- Slowed heart rate
- Impaired memory
- Enlarged thyroid gland (goiter)
Cases of hypothyroidism are on the rise
However, it's clear from the research that the prevalence of hypothyroidism is on the rise. This increase could be the result of more testing. Empowered and informed patients may be requesting that doctors run thyroid tests more frequently. Or greater awareness of hypothyroidism may be prompting doctors to test more of their patients. At the same time, there may also be a genuine increase in hypothyroidism in the population. This increase could be due to environmental factors, diet and nutrition, or other causes that require further study.
An equally perplexing question is why there is an increase in hypothyroid patients who are not receiving treatment from their healthcare provider. Is this a result of patients refusing medication? Are providers deciding that mild or subclinical hypothyroidism doesn't warrant treatment? Do patients think that treatment is unaffordable, even with medical insurance? Unfortunately, the study did not explore these issues.
A note from Paloma Health
Findings like these are, in part, why Paloma Health exists. We offer easy, at-home thyroid blood tests and virtual consultations with thyroid doctors to safely restore your thyroid function. Our services are fast, private, personalized, and very affordable—whether or not you have health insurance. Paloma Health's providers are experts in diagnosing and treating hypothyroidism—effectively. And, with Paloma Health's personalized follow-up and a high degree of patient support, no hypothyroid patients who want or need testing and treatment are left behind!
- Pinsky, Brett et. al. "Prevalence of Hypothyroidism in a Commercially Insured US Population: A Retrospective Claims Database Study from 2012 – 2018," American Thyroid Association Annual Meeting Clinical Poster, Poster 251, https://www.liebertpub.com/doi/10.1089/thy.2021.29118.lb.abstracts
- US Census Bureau, Population Under Age 18 Declined Last Decade, August 12, 2021, https://www.census.gov/library/stories/2021/08/united-states-adult-population-grew-faster-than-nations-total-population-from-2010-to-2020.html