Older adults with hypothyroidism face elevated risk of death

by The Endocrine Society

Credit: CC0 Public Domain

While older adults with hypothyroidism face an elevated risk of death, individuals with subclinical hypothyroidism, a milder form of underactive thyroid, did not face the same risk, according to new research published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism.

15 dec 2019--Hypothyroidism occurs when the body produces too little thyroid hormone. Thyroid hormone controls a person's metabolism and affects the way the body uses energy, consumes oxygen and regulates temperature. The condition occurs more often in women and people over the age of 60.

"Our meta-analysis is the first to evaluate and confirm the association between hypothyroidism and mortality, specifically focusing on an older population," said Carol Chiung-Hui Peng, M.D., of the University of Maryland Medical Center Midtown Campus in Baltimore, Md., and one of the study's authors.

"Our analysis found individuals with hypothyroidism aged 60 years or older were 26 percent more likely to die from all causes than individuals in the same age range who did not have the thyroid condition," said co-author, Huei-Kai Huang, M.D., of Hualien Tzu Chi Hospital and Tzu Chi University in Hualien, Taiwan.

The researchers reviewed the results of 27 published articles including over 1.1 million older individuals. Although hypothyroidism was associated with all-cause mortality risk, the studies did not find a higher incidence of cardiovascular mortality. Interestingly, studies published in Asia and North America were associated with increased all-cause mortality in the hypothyroid population, while those published in Europe and Oceania were not. Among individuals with hypothyroidism who were 80 years old or older, the researchers found no increased risk of all-cause or cardiovascular mortality.

The mortality difference was not seen in older patients with milder forms of thyroid disease. This study provides further evidence to help guide management of hypothyroidism in older adults.

"In accordance with guidelines, our findings imply that individuals with subclinical hypothyroidism—those who have milder thyroid dysfunction—may not benefit from being treated with synthetic thyroid hormone," said Kashif M. Munir, M.D., associate professor in the division of endocrinology, diabetes and nutrition at the University of Maryland School of Medicine in Baltimore, Md., and another of the study's authors. "However, treatment should be considered in individuals diagnosed with hypothyroidism, given increased all-cause mortality."

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More information: Tou-Yuan Tsai et al, Association of hypothyroidism and mortality in the elderly population: A systematic review and meta-analysis, The Journal of Clinical Endocrinology & Metabolism (2019). DOI: 10.1210/clinem/dgz186

Journal information: Journal of Clinical Endocrinology & Metabolism 

Provided by The Endocrine Society 

Overtreating patients for hypothyroidism could raise their risk of stroke, study finds

For patients who take medication to treat hypothyroidism, being treated with too much medication can lead to an increased risk of atrial fibrillation, a common heart rhythm disorder associated with stroke, a new study of more than 174,000 patients has found. Credit: Intermountain Medical Center Heart Institute

14 nov 2018--For patients who take medication to treat hypothyroidism, being treated with too much medication can lead to an increased risk of atrial fibrillation, a common heart rhythm disorder associated with stroke, a new study of more than 174,000 patients has found.
The findings were presented by researchers from the Intermountain Medical Center Heart Institute in Salt Lake City at the American Heart Association Scientific Session conference in Chicago.
"We know patients with hypothyroidism have a higher risk of atrial fibrillation, but we didn't consider increased risk within what's considered the normal range of thyroid hormones," said lead researcher Jeffrey L. Anderson, MD, Distinguished Clinical and Research Physician at the Intermountain Medical Center Heart Institute, which is part of the Intermountain Healthcare system. "These findings show we might want to re-consider what we call normal."
In the new study, researchers surveyed the electronic medical records of 174,914 patients treated at Intermountain Healthcare facilities whose free thyroxine (fT4) levels were recorded and who were not on thyroid replacement medication. Researchers then took what's considered a normal range of fT4 levels, divided it into four quartiles, then looked at those patients' records for a current or future diagnosis of atrial fibrillation.
They found a 40 percent increase in existing atrial fibrillation for patients in the highest quartile of fT4 levels compared to patients in the lowest, and a 16 percent increase in newly developing atrial fibrillation during 3-years of follow up.
These findings, said Dr. Anderson, suggest that the optimal healthy range of fT4 should be reconsidered and redefined.
"Thyroid hormones are associated with losing weight and having more energy, which may lead to people being treated at the high end of the normal range," said Dr. Anderson. "Are we harming people by putting them at a higher risk of atrial fibrillation, and therefore stroke?"
The study also showed that fT4 should be measured, along with thyroid-stimulating hormone (TSH), which is more commonly tested for in patients with irregular thyroid hormone levels but was not helpful within the normal range in refining risk.
The link between fT4 and atrial fibrillation was recently recognized in the Rotterdam Study, a population-based cohort study first started in 1990. However, with any new and unexpected report requires replication and independent confirmation. The new study by Intermountain Medical Center Heart Institute researchers establishes the link between fT4 level and atrial fibrillation in patients treated in the United States.
"The next step for researchers is to conduct a randomized trial to see if targeting a lower versus a higher upper range of fT4 in patients receiving thyroid hormone replacement therapy leads to a lower risk of atrial fibrillation and stroke along with other possible heart-related issues, like atherosclerosis," Dr. Anderson said.


Provided by Intermountain Medical Center

Hypothyroidism linked to liver cancer in women

NEW YORK, 16 may 2009– Women with long-standing hypothyroidism, commonly referred to as an "underactive thyroid," are at increased risk of liver cancer, the results of a new study suggest. By contrast, hypothyroidism is not significantly associated with this malignancy in men.

Hypothyroidism is a condition in which the thyroid gland fails to produce enough thyroid hormone. The thyroid gland normally releases the hormones, T4 and T3, that control metabolism and underproduction may affect all body functions. Risk factors for hypothyroidism include: being older than 50 years of age, exposure of the neck to X-ray or radiation treatments, female gender, obesity and thyroid surgery.

Thyroid hormones are known to be involved in lipid metabolism and fatty acid oxidation and there is evidence linking hypothyroidism with nonalcoholic steatohepatitis - the fatty inflammation of the liver cells -- according to the report in the current issue of Hepatology. However, whether thyroid disorders are associated with liver cancer has been unclear.

To answer this question, Dr. Manal M. Hassan, from the University of Texas M. D. Anderson Cancer Center, Houston, and colleagues compared the occurrence and nature of thyroid disease in 420 patients with hepatocellular carcinoma, the most common type of liver cancer, and a group of 1104 healthy individuals without hypothyroidism.

After accounting for factors that could influence the patients' outcome, such as demographic factors, alcohol use, family history of cancer, and other possible confounders, Hassan's group found that women who had hypothyroidism for longer than 10 years were 2.9-times more likely to develop liver cancer than those without thyroid disease. If the patients also had diabetes and chronic hepatitis virus infection, the odds ratios increased to 9.4-times and 31.2-times, respectively.

As noted, hypothyroidism did not affect the risk of liver cancer in men.

Hyperthyroidism, an "overactive thyroid," also had no impact on the risk of liver cancer in either sex.

"Further studies among different populations are warranted to confirm the association between hypothyroidism and (liver cancer) and to identify the underlying biological mechanisms and the genetic predisposition factors that may contribute to susceptibility to hepatocellular carcinoma development in the presence of thyroid disorders," the authors conclude.

SOURCE: Hepatology, May, 2009.