White, Female Patients May Face Higher Risk of Hypothyroidism
White women with sarcoidosis and multiorgan involvement may be at a higher risk of hypothyroidism, or low thyroid gland activity, than other people with the overactive immune system disorder, according to a study of more than 3,800 patients in the U.S.
In fact, hypothyroidism — which is significantly associated with fatigue, depression, fibromyalgia, obesity, and sleep breathing disorders — was reported in 14% of sarcoidosis patients, the data show.
While the causes of hypothyroidism in sarcoidosis patients remain unclear, these findings suggest that the possibility of an underactive thyroid should be assessed as a potential co-existing condition. That is especially the case in patients with multiorgan involvement, fatigue, and depression, the researchers noted.
The study, “Prevalence and characteristics of self-reported hypothyroidism and its association with nonorgan-specific manifestations in US sarcoidosis patients: a nationwide registry study,” was published in the journal ERJ Open Research.
Sarcoidosis is a highly variable inflammatory disease that can lead to the formation of small abnormal lumps or nodules — called granulomas — in virtually any organ in the body, most commonly the lungs.
Previous studies have suggested that sarcoidosis patients are at higher risk for hypothyroidism, and for the abnormal production of antibodies against the thyroid, also impairing its activity.
However, the exact frequency, clinical characteristics, and impact of hypothyroidism in sarcoidosis patients remain largely unknown.
To address this knowledge gap, researchers in the U.S., in collaboration with the Foundation for Sarcoidosis Research (FSR), analyzed data from 3,822 sarcoidosis patients who responded to FSR’s Sarcoidosis Advanced Registry for Cures Questionnaire between June 2014 and August 2019.
The self-reported, web-based questionnaire provided data related to demographics, diagnostics, organ involvement, manifestations such as hypothyroidism, physical and psychosocial impact, and treatment of sarcoidosis.
According to the researchers, this was the largest published study to assess the frequency, characteristics, and potential impact of an underactive thyroid in sarcoidosis patients.
The results showed that hypothyroidism was reported by 538 (14.1%) patients, who were significantly older (45.1 vs. 43.1 years), and more frequently women (90% vs. 71%) and white (91% vs. 78%) than those who did not report the thyroid condition.
This frequency of hypothyroidism was “remarkably higher than what is reported in the general population, which ranges between 3% and 7% in the United States,” the researchers wrote. It was, however, similar to “what has been observed in other smaller sarcoidosis [groups],” the team wrote.
Notably, 20% of all white female patients involved in the study reported having symptoms of hypothyroidism.
In addition, a significantly greater proportion of patients with self-reported hypothyroidism reported multiorgan involvement (51% vs. 46%), and more of them had manifestations in the skin, eyes, joints, liver, and lacrimal glands, involved in tearing of the eyes.
Simultaneous health conditions related either to sarcoidosis or to corticosteroid use also were significantly more frequent in the hypothyroidism group than among those without an underactive thyroid.
The researchers then looked at potential links between hypothyroidism and other manifestations, since the condition has previously been associated with depression, obesity, sleep apnea — when breathing stops and restarts during sleep — chronic fatigue, and fibromyalgia in the general population. Of note, fibromyalgia is a condition associated with widespread pain and fatigue.
When adjusting for potential influencing factors, self-reported hypothyroidism was significantly associated with obesity, sleep apnea, chronic fatigue, depression, antidepressant use, and fibromyalgia.
Sarcoidosis patients with hypothyroidism also were significantly more likely to have missed more than seven work days in the previous year, or to terminate their jobs due to their illness, suggesting they experienced greater physical impairment.
When a University of Florida database with an additional 2,189 adults with sarcoidosis were examined, the researchers obtained similar findings. Notably, a greater proportion of African American patients were included in this group as compared with the online survey respondents (38% vs. 18.5%).
Those results showed that 15% of patients had hypothyroidism, which was significantly associated with depression, fatigue, fibromyalgia, obesity, and sleep apnea, suggesting that the study’s findings may be generalized to the overall sarcoidosis patient population.
Also, given that chronic fatigue was previously associated with depression, obesity, sleep apnea, and fibromyalgia, this study’s findings suggest that “fatigue in sarcoidosis is multifactorial and may also be linked to hypothyroidism,” the team wrote.
The data highlighted that “hypothyroidism is a frequent comorbidity in sarcoidosis patients, is often associated with sarcoidosis multiorgan involvement, and might be a potentially reversible contributor to fatigue, depression and physical impairment in this population,” they added.
“We recommend considering routine screening for hypothyroidism in sarcoidosis patients especially in those with multiorgan sarcoidosis, fatigue and depression,” the researchers wrote.
Still, whether hypoparathyroidism in this patient population is caused by the formation and accumulation of granulomas inside the thyroid, by sarcoidosis-associated abnormal immune responses, or by the use of certain hypoparathyroidism-causing medications remains unclear, the team noted.
Further research is needed to better understand the causes of hypothyroidism in sarcoidosis, identify common disease-associated pathways, and assess the impact of hypothyroidism in non-organ-specific symptoms in sarcoidosis patients.
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