High Cholesterol Check Your Thyroid

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High Cholesterol Check Your Thyroid

By Sally Squires

Washington Post Staff Writer

Tuesday , February 22, 2000 ; HE8

If you're among the 35 million Americans with elevated cholesterol levels,

ask

your doctor about getting tested for thyroid disease. Estimates are that up

to

14 percent of people with elevated cholesterol may also have an underactive

thyroid ­ and that treatment of the thyroid condition can help reduce

cholesterol levels.

" People who have a total cholesterol level of 240 or more should have a

thyroid

test done before they start any diet or drug therapy, " said

Kwiterovich,

chief of the lipid research atherosclerosis program at s Hopkins Medical

Institutions in Baltimore. Having too little thyroid hormone can contribute

to

cholesterol problems, complications and treatment, Kwiterovich says.

None of this means that genes and diet ­ long associated with heart disease

­

are less important. Along with being overweight, eating a high-fat,

high-cholesterol diet and having a family history of cholesterol problems

remain the leading risk factors for developing high blood cholesterol levels

and related risks of heart disease. But growing scientific evidence points

to

thyroid deficiency as a contributor to elevated cholesterol and other health

problems.

" The message here is that hypothyroidism [thyroid deficiency] can also be a

common cause of high blood cholesterol levels, " said Ladenson, director

of

the division of Endocrinology and Metabolism at s Hopkins. The thyroid

condition should be diagnosed, he said, " because reversing it can either

completely correct the high cholesterol or make it easier to treat with

other

measures. "

Tucked below the Adam's apple in the neck, the thyroid is a small,

butterfly-shaped gland that regulates metabolism by releasing hormones. The

brain communicates with the thyroid by sending chemical messages transmitted

via the pituitary gland, which acts as a kind of thermostat, turning thyroid

production up and down as needed. To complete the loop, circulating thyroid

hormones signal the brain to boost or drop thyroid production.

For about 3 percent of people with elevated blood cholesterol levels,

thyroid

deficiency is the sole problem, according to Kwiterovich. Once the

deficiency

is diagnosed and treated, blood cholesterol levels quickly return to normal.

Detection occurs with a simple blood test that costs about $25. Treatment

consists of daily replacement with thyroid hormone ­ thyroxin ­ given in a

tiny

pill that costs less than 50 cents per day. Hypothyroidism is far more

common

among women than men.

Doctors are also coming to appreciate ­ especially with regard to the

cholesterol connection ­ the damage from a less severe form of

hypothyroidism.

Often called " subclinical " because it produces no real symptoms, this type

of

thyroid deficiency occurs in about 10 percent of women, several studies have

suggested. Not only does it complicate treatment of elevated blood

cholesterol

levels, but it may also increase the risk of heart disease.

The latest evidence about subclinical hypothyroidism comes from a Dutch

study

of elderly women published last week in the ls of Internal Medicine.

Researchers from Erasmus University Medical School in Rotterdam found that

women with low levels of thyroid hormone were twice as likely to have

clogged

arteries and to have suffered a heart attack as women with normal levels.

" I was kind of awestruck that hypothyroidism could have such a strong

effect, "

said Ladenson. " It's time to throw out the word 'subclinical' especially in

light of this new evidence that there are clinical consequences associated

with

this mild thyroid deficiency. "

Thyroid function appears to affect heart disease risk in multiple ways. In

the

liver, thyroid hormone determines how well the most harmful form of

cholesterol

­ low-density lipoprotein (LDL) ­ is removed from the blood by increasing

the

number of LDL receptors in the liver.

Thyroid deficiency can also selectively increase diastolic blood pressure

(the

pressure on vessels when the heart rests between beats), increase blood clot

formation and elevate other substances, including homocysteine, that

increase

heart disease risk. It can also cause complications for those taking

cholesterol-lowering medications.

The good news is that detection and treatment of thyroid deficiency can

significantly lower health risks. " I have seen women and men who had

hypothyroidism and a blood cholesterol level of 230 that went down to 200

just

with treatment of their thyroid problem, " said Margo Denke, a Dallas

cardiologist and a member of the National Cholesterol Education Program's

Adult

Treatment Panel.

The problem is that screening for thyroid problems is still spotty at best,

even among high-risk groups. A recent survey by the American Association of

Clinical Endocrinologists (AACE) found that more than half of people with

elevated blood cholesterol had not had their thyroid levels checked. " That's

a

big problem, " said the AACE's president, A. Dickey.

For this reason, the AACE is urging consumers with elevated blood

cholesterol

levels to ask their physicians about thyroid testing.

" If they have an underlying thyroid condition in addition to their high

cholesterol, " Dickey said, " the cholesterol problem will be difficult to

control until normal levels of thyroid hormone are restored. "