What Are the Health Effects and Symptoms of Having an Underactive Thyroid?
How prevalent are thyroid conditions?
Check out these jaw-dropping stats about thyroid conditions in general. According to the American Thyroid Association:1
- More than 12% of the U.S. population will have a thyroid condition at some point in their lives.
- Three out of five individuals have an undiagnosed thyroid condition.
- 20 million Americans have thyroid disease.
- Thyroid dysfunction increases the risk for a number of conditions, including heart disease, osteoporosis, and infertility.
- Women are 5-8 times more likely to have a thyroid abnormality than men (with one in eight developing a thyroid condition at some point in her life).
- Hypothyroidism affects as many as 20% of women over age 50.2
- Pregnant women with an underactive thyroid are at increased risk for miscarriage, pre-term delivery, and giving birth to a baby with a developmental disability.
What are signs and symptoms of an underactive thyroid?
An underactive thyroid produces less than optimal levels of thyroid hormones that are necessary for healthy metabolic functioning – the end result being an overall slowdown of metabolism. The most well-recognized symptoms of low thyroid function include:
- Weight gain
- Joint and muscle pain
- Sensitivity to cold
- Cold hands and feet
- Difficulty concentrating
- Mental fogginess
- Dry skin and hair
- Frequent and heavy periods
- Slowed heart rate (less than 60 beats per minute)
- Slow deep-tendon reflexes
- Swelling in the neck from an enlarged thyroid gland (can also be present with overactive thyroid)
Other less classic symptoms that might not be so easily linked to low thyroid include:
- Low or no sex drive
- Difficulty getting out of bed in the morning
- Unexplained numbness, tingling, or twinges in muscles
- Abnormal sense of taste – things just don’t taste right
Even a borderline-underactive thyroid is associated with certain health concerns.
Recent studies have found that thyroid-stimulating hormone (TSH) levels even at the upper limit of normal can increase the risk for certain health problems (elevated TSH levels are associated with underactive thyroid function).
In a recent study at a large academic health clinic, women with unexplained infertility had significantly higher levels of TSH – although still in the high normal range – than women who weren’t having fertility issues.3
Two studies – one on individuals with heart disease4 and the other on “healthy” individuals having routine medical testing5 – found that those with TSH levels at the upper limit of normal (with normal T3 and T4) were more likely to have elevated cholesterol than individuals with lower TSH levels (but still in the normal range).
A new study (published January 2018) has found an association between abdominal fat accumulation and high-normal TSH levels in women and older subjects of both genders.6 Elevated LDL-cholesterol and triglycerides were also associated with borderline high TSH levels.
More than 700 individuals with “normal” thyroid function were tested with ultrasound for the presence of fatty liver, and 196 met the diagnostic criteria for non-alcoholic fatty liver (NAFLD). Compared to those without fatty liver, subjects with NAFLD had lower free T4 and higher TSH (although still within normal limits).7
What do these results mean? It means a “clean bill of health” after a routine thyroid health screening might merit a second look.
- TSH – the hormone secreted by the pituitary gland in the brain that signals the thyroid gland to produce thyroid hormones. Circulating thyroid hormones then signal the brain to secrete more or less TSH as the brain senses is necessary.
- T3 – one of the two major hormones made by the thyroid gland. T3 is more potent than T4 – meaning it has a stronger action on those bodily tissues with receptors for thyroid hormone. T3 regulates metabolism, body temperature, weight, energy, and heart health.
- T4 – the hormone made in the greatest quantity by the thyroid gland. T4 can also be converted to T3 and it has the same actions as T3, but it’s not as strong.
- TPOAb – antibodies against thyroid peroxidase (an enzyme necessary to produce T3 and T4). TPO antibodies can attack the thyroid gland, causing inflammation and dysfunction.
Who should take the Thyroid Home-Test?
- Anyone who exhibits symptoms described above that can’t be explained by some other health problem.
- An individual with health conditions (such as elevated LDL-cholesterol, fatty liver, or obesity) that can’t be explained by diet and lifestyle or other health-related factors.
- A woman with unexplained infertility.
Keep in mind
Testing is only a tool and it does not replace a health-care practitioner’s expertise and guidance. It is important to consult a professional health-care practitioner if you suspect a thyroid problem.
- American Thyroid Association https://www.thyroid.org/media-main/about-hypothyroidism/ [Accessed 1.16.18]
- https://my.clevelandclinic.org/health/diseases/12120-hypothyroidism [Accessed 1.29.18]
- Orouji-Jokar T, Fourman L, Lee H, et al. Higher TSH levels within the normal range are associated with unexplained infertility. J Clin Endocrinol Metab 2017 Dec 19. doi: 10.1210/jc.2017-02120. [Epub ahead of print]
- Wanjia X, Chenggang W, Aihong W, et al. A high normal TSH level is associated with an atherogenic lipid profile in euthyroid non-smokers with newly diagnosed asymptomatic coronary heart disease. Lipids Health Dis 2012;11:44. doi: 10.1186/1476-511X-11-44
- Wang F, Tan Y, Wang C, et al. Thyroid-stimulating hormone levels within the reference range are associated with serum lipid profiles independent of thyroid hormones. J Clin Endocrinol Metab 2012;97:2724-2731.
- Chen Y, Chen Y, Wang N, et al. Thyroid stimulating hormone within the reference range is associated with visceral adiposity index and lipid accumulation product: a population-based study of SPECT-China. Horm Metab Res 2018;50(1):29-36.
- Tao Y, Gu H, Wu J, Sui J. Thyroid function is associated with non-alcoholic fatty liver disease in euthyroid subjects. Endocr Res 2015;40(2):74-78.
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