Despite undergoing treatment for an underactive thyroid, or hypothyroidism, that successfully restores normal levels of hormones produced by the thyroid gland, nearly 15 percent of people with the condition complain they still feel depressed, sluggish and suffer from mental fog, according to recent findings published in the Journal of Clinical Endocrinology and Metabolism, ScienceDaily reports.
Hypothyroidism occurs when the thyroid gland, located in the neck, stops producing enough hormones, most commonly due to an autoimmune disorder. Since one of the thyroid’s primary jobs is to regulate metabolism, a faulty gland can affect almost every organ and function in the body. Hypothyroidism affects an estimated 10 to 12 million Americans, and women are much more likely to develop the condition. To treat an underactive thyroid, physicians routinely prescribe levothyroxine, a synthetic version of the thyroid hormone thyroxine (T4), that stabilizes blood levels of TSH, or thyroid-stimulating hormone. (Until the 1970s, doctors used pills containing thyroxine and another thyroid hormone, triiodothyronine, a.k.a. T3, to treat the disease.)
For the study, researchers at Rush Medical School in Chicago evaluated the health of 469 adults on levothyroxine therapy in the U.S. National Health and Nutrition Examination Survey (NHANES) and compared them to 469 individuals who were not on it. Both groups were matched for age, sex, race and serum TSH levels.
Next, researchers checked to see how 52 clinical measures differed between the two groups. Findings showed that individuals taking levothyroxine weighed about 10 pounds more than their peers of the same height despite consuming fewer calories. In addition, these patients were significantly more likely than those with normal thyroid function to take antidepressants and to use beta-blockers and statins. (Doctors frequently prescribe beta-blockers to lower blood pressure; statins help reduce cholesterol levels.)
“They have difficulty losing weight. They complain of feeling sluggish and have less energy. Yet we doctors keep telling them ‘I’m giving you the right amount of medication and your TSH is normal. You should feel fine,” said Antonio C. Bianco, MD, PhD, a professor of medicine at Rush and former president of the American Thyroid Association, one of the study’s authors.
Scientists feel these results offer patients strong evidence that they’re not just imagining the persistence of their symptoms. They suggested that hypothyroid patients on levothyroxine monotherapy with normal TSH levels who still suffer from signs of the disease talk to their physicians about modifying their therapy to help them feel better.
The American Thyroid Association is currently conducting clinical trials of a combination therapy that, once again, features T3 and T4 in one pill. So far the treatment has worked for some patients but not others. In addition, researchers urged physicians to change the way they talk about hypothyroidism with patients and to acknowledge that better medications are needed to treat the condition.
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