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| FOR IMMEDIATE RELEASE Sept. 17, 2003, 2:45 p.m. EDT |
Media Contact: Melanie Caudron melanie.caudron@verizon.net |
Mild Thyroid Failure and High Cholesterol May
Go Hand in Hand,
Changing Treatment Protocol
(PALM BEACH, FLA., Sept. 17, 2003) - People who have even mildly high
blood levels of a hormone, called thyroid-stimulating hormone (TSH), may
have elevated blood cholesterol levels, according to the findings of a
new study presented today at the 75th Annual Meeting of the American Thyroid
Association. Elevated levels of lipids, such as cholesterol and triglycerides,
can lead to heart disease and heart attacks by clogging the coronary arteries.
"This finding is important because elevated blood TSH levels are
present in 5 percent of the total adult U.S. population and in about 10
percent of those over age 60," said Elizabeth N. Pearce, MD, lead
author of the study and instructor of medicine at Boston Medical Center
and Boston University School of Medicine in Boston. "Moreover, there
is no clear consensus at present on whether patients with mildly elevated
TSH should be treated with thyroid hormone."
Past studies have clearly shown that patients with more severe hypothyroidism
have elevated total cholesterol and LDL cholesterol levels. However, observational
studies in patients with subclinical hypothyroidism - also known as mild
thyroid failure - have been less consistent, some showing cholesterol
elevations in patients with subclinical hypothyroidism and some showing
no lipid effects.
For this reason, Dr. Pearce and colleagues in Boston analyzed the records
of a group of people from the Framingham Offspring study, which includes
participants who are representative of the general population. The study
sample included 1,742 men and 1,722 women, between the ages of 41 and
61 years old, who had their blood tested for TSH and fasting lipid levels
between 1987 and 1990. Anyone who was taking lipid-lowering medications
was excluded from the study.
Nearly 76 percent of men and 73 percent of women had normal TSH levels
(0.5-2.5 mU/L), nearly 20 percent of men and 16 percent of women had high-normal
TSH (2.5-5 mU/L), less than 2 percent of men and 3 percent of women had
mildly elevated TSH (5-10 mU/L), and nearly 1 percent of men and 3 percent
of women had clearly elevated TSH (>10 mU/L).
Average total cholesterol and triglyceride levels differed significantly
across TSH categories in both men and women. LDL ("bad") cholesterol
levels differed significantly across TSH categories in women, but the
differences were of only borderline significance in men. Total cholesterol,
LDL, and triglyceride levels were greater across increasing TSH categories
for women. There was an overall trend of increasing total cholesterol
and triglycerides across increasing TSH levels in men but it was not a
consistent increase. There were no significant differences in HDL ("good")
levels across TSH categories.
"Our findings provide more evidence that there may be adverse lipid
effects even with minimal elevations in serum TSH values," added
Dr. Pearce. "We would now be more likely to consider thyroid hormone
treatment in patients with mild thyroid failure who also have high cholesterol
levels"
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