This explanation, of course, is much needed. CFS, already a complicated disorder, cannot be explained by any underlying medical condition. At best, there are theories on how people get the condition, which range from viral infections to psychological stress. According to the Centers for Disease Control and Prevention (CDC), up to 2.5 million people in the U.S. have CFS; however, most of them remain undiagnosed. Currently, there is no effective cure for the condition, with treatments mainly focusing on addressing symptoms as they appear.
The study, however, pointed out that these symptoms are very similar to hypothyroidism, an endocrinal disorder where the thyroid gland does not produce enough hormones. What differs, however, is how the body reacts to the condition: In hypothyroidism, the body releases hormones to stimulate thyroid function, which does not happen in cases of CFS. This led researchers to suggest the link between CFS and lower thyroid activity. (Related: Hypothyroidism Reaches Epidemic Proportions, Causing Fatigue and Weight Gain.)
To test their theories, the researchers, led by Dr. Begoña Ruiz-Núñez of the University Medical Center Groningen in the Netherlands, examined thyroid function and inflammation markers for both people with CFS and those without the condition – a total of 98 patients with CFS and 99 healthy people used as controls. Based on the results, they found that those with CFS had lower levels of key thyroid hormones such as triiodothyronine (T3) and thyroxine (T4), but normal levels of thyroid-stimulating hormone. T3, in particular, is a hormone that regulates functions such as metabolic rate, heart and digestive functions, muscle control, cognitive development and function, and bone maintenance. T4, the main hormone released into the bloodstream by the thyroid gland, is mainly used by the liver and kidneys.
CFS patients also had lower levels of iodine in their urine and low-grade inflammation, both of which are also symptoms of hypothyroidism. A stark difference between the two conditions, however, is the increased level of a thyroid hormone called "reverse T3" or rT3 in patients with CFS. Researchers posited that this could be an indication of a shift in hormone production, where the body converts T4 to rT3 instead of T3. This leaves the body severely starved of T3 hormones in tissue.
"One of the key elements of our study is that our observations persisted in the face of two sensitivity analyses to check the strength of the association between CFS and thyroid parameters and low-grade inflammation," explained Dr. Ruiz-Núñez. "This strengthens our test results considerably."
The team also suggested that adding certain information in future studies could establish a stronger link between the condition and a patient's biochemical profile. While the study explores a possible link between CFS and certain thyroid levels, they maintain that there is still no definitive cause for CFS.
"Our study needs confirmation and extension by others," the researchers concluded. "If confirmed, trials with, e.g., T3 and iodide supplements might be indicated."
Learn more about CFS and hypothyroidism by heading to Health.news today.