Even Mild Thyroid Problems Double Risk

 Of Heart Condition

Science Daily —
Individuals with subclinical hypothyroidism—a mildly underactive
thyroid only detectable by a blood test—are twice as likely to develop
heart failure, compared to those with normal thyroid levels, according
to a new study. Heart failure, also called congestive heart failure, is
when the heart can’t pump enough blood to the body’s other organs,
which can cause fatigue, ankle swelling and shortness of breath.

Although previous studies have shown that
hyperthyroidism—an overactive thyroid—and hypothyroidism can cause
heart problems, this is the first time that a large study found a
negative effect on heart function when the thyroid was only mildly
under-active.

“If other studies confirm these findings, then
physicians might want to consider treating mild thyroid problems to
prevent potential cardiac problems or to avoid increasing the severity
of an existing heart condition,” said Doug Bauer, M.D., an author of
the study and a Professor of Medicine, Epidemiology and Biostatistics
at the University of California at San Francisco School of Medicine in
San Francisco.

Subclinical thyroid disorders are detected by a
blood test that evaluates the levels of thyroid-stimulating hormone
(TSH). Subclinical hypothyroidism is defined by TSH levels greater than
4.5 mU/L and normal free thyroxine levels. Individuals with subclinical
hypothyroidism can evolve into overt hypothyroidism, where the free
thyroxine levels fall below normal, which always requires thyroid
hormone therapy.

The Cardiovascular Health Study involved over
3,000 adults 65 years and older, who were evaluated to determine if
those individuals who had subclinical hypothyroidism had an increased
risk of developing heart failure over a twelve-year period. The study
shows that individuals who had a TSH level equal or greater than 10
mU/L had a two-fold risk of developing heart failure, compared to those
who had normal thyroid levels.

This research was presented on Oct. 4, at the 78th Annual Meeting of the American Thyroid Association (ATA) in New York.

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