Thyroid hormone treatment intensity linked to higher death risk in heart disease

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One synthetic thyroid hormone, levothyroxine, lands itself on the United State’s list of top three prescribed medications in the country over the last decade.

Simultaneously, despite all efforts to reduce its prevalence, heart disease remains the leading cause of death in Americans, affecting nearly half of the population aged 20 years and older.

In a study from the University of Michigan, scientists found that thyroid hormone treatment intensity is linked to an increased risk of heart death.

In the study, the team aimed to examine the link between thyroid hormone treatment intensity and heart death in more than 705,000 U.S. veterans who received thyroid hormone therapy between 2004 and 2017.

The team followed an observation that up to half of the patients who receive thyroid hormone therapy have exogenous hyperthyroidism or hypothyroidism, which is having thyrotropin levels inappropriately below or above the normal range, respectively.

They found that these patients did have an increased risk for heart death compared to those with normal thyroid function.

The findings suggest that the intensity of thyroid hormone treatment could be a modifiable risk factor for heart disease, and that thyrotropin levels lower than 0.1 mIU/L and higher than 20 mIU/L are of particular concern for this outcome.

Notably, the team found those in older age categories are a vulnerable population for these adverse health outcomes and should be targeted for interventions to avoid over-and under-treatment with thyroid hormone.

Patients with a history of thyroid cancer were excluded from the study because lower thyrotropin levels are often targeted in these patients to reduce the risk of cancer recurrence.

Additionally, patients prescribed lithium or amiodarone were excluded because of the medications’ link with abnormal thyroid function results.

These findings emphasize the importance of maintaining euthyroidism to decrease heart disease risk and death among patients receiving thyroid hormone treatment.

If you care about heart health, please read studies about how eating eggs can help reduce heart disease risk, and herbal supplements could harm your heart rhythm.

For more information about heart health, please see recent studies about how espresso coffee affects your cholesterol level, and results showing Vitamin C, but not vitamin E, linked to a lower risk of heart failure.

The research was published in JAMA Network Open and conducted by Maria Papaleontiou et al.

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