Wisdom Wednesday: Your Thyroid Could Be Working Against Your Heart

Middle-aged and older adults with an elevated thyroid hormone may be at higher risk of heart disease and death, researchers found. In the new Dutch study, high and even high-normal levels of a hormone called free thyroxine (FT4) doubled the odds of having calcification of the coronary arteries. This can be a sign of atherosclerosis, commonly called hardening of the arteries.

Higher FT4 levels were also linked to an 87% greater risk of having a heart attack or stroke and twice the risk of dying from one. “High FT4 is indicative of an overactive thyroid,” explained lead researcher Dr. Arjola Bano, of Erasmus University in Rotterdam.

FT4 is produced in the thyroid gland at the front of the neck. It helps control the body’s rate of energy use, she said. Atherosclerosis means you have fatty deposits called plaque that can clog arteries. As plaque builds up, the artery narrows, reducing blood flow. Atherosclerosis can progress from thickening and hardening to the artery walls to heart disease, stroke and death, Bano said.

“Our findings suggest that FT4 measurement can help identify people at increased risk of atherosclerotic events,” she added.



This study shows an association, but doesn’t prove that FT4 boosts the risk for heart disease, said Dr. Byron Lee, director of electrophysiology laboratories at the University of California, San Francisco. “The FT4 could be the cause or simply a marker,” Lee said. “Either way, this warrants further exploration, and patients with high FT4 should be on the lookout.”

The report was published online Oct. 31 in the journal Circulation Research.

My Take:
FT4 is the inactive form of thyroid hormone. Chemically, it is a molecule of cholesterol with four iodine molecules attached, hence the name T4. As noted above, it is produced in the thyroid gland and released into general circulation. The active form, T3 is created in the liver by chopping one of the iodine molecules off. This chemical process is under the control of the adrenal glands.

Clinically, a clear majority of patients I see with a high or normal-high FT4 are taking Synthroid. Synthroid is synthetic T4 and is the third most commonly prescribed drug in the world. It was number one for many years, but was displaced by a couple of statin drugs.

Underactive thyroid metabolism is one aspect of metabolic syndrome and has long been associated with heart disease. Hypothyroidism has been on the rise in the United States since iodine was removed as a preservative in all baked goods in the early ‘60’s. It was replaced by BHT and other carcinogens.

Autoimmune disease is also a big factor in the rise of hypothyroidism as fully a third of women diagnosed with this disease are thought to have Hashimoto’s thyroiditis, producing antibodies that attack and destroy the thyroid gland.

The Bottom Line:
Please request that the lab perform a T3 and T4 in addition to the routine TSH on your annual laboratory testing. Pay attention to all the lab values, even if they are within medical norms. The TSH should be between 1 and 2, although the “medical norm” is 0.4 to 4.5.

If you are taking Synthroid or any other thyroid medication, I highly recommend you have a high-speed CT scan of the heart. The calcium score from this test will identify vulnerable plaque ten years before it may show on a cardiac stress test.

Source: October 31, 2017 National Institutes of Health