Unmasking thyroid trouble

Could this little gland be the cause of all your ills?

Let's say you're a woman in your late 40s. You've embarked on menopause, the big ship of change. You feel a little blue; you've gained a little weight; your energy's a little low. Drying skin, thinning hair, a nonstick memory. They're only natural, you think. But menopause ends, and the symptoms persist. You don't feel awful--you just feel off.

"Most women accept problems like that because they're so common in menopause," says Prevention reader Mary-Beth Hayden, RN. "I would have disregarded them, too, if it weren't for my walking."

Instead of the pep they usually gave her, power walks were sapping her strength. "I felt like a snail," she says. That was so peculiar and went on so long that the nurse from Long Island asked her doctor to check her thyroid. Sure enough. Hayden's problem wasn't change of life but change of hormones--not estrogen but the thyroid gland's main elixir, thyroxine. Her thyroid wasn't producing enough thyroxine and so was underactive (a condition called hypothyroidism). This scarcity of thyroxine put her metabolism on SLOW, which sapped her energy and caused a host of other menopause-like symptoms.

The solution was simple. Hormone medication bolstered Mary-Beth Hayden's low supply. Her logy thyroid started purring again.

Remember the movie Zelig, where actor Woody Allen turned into an assortment of historical figures? Well, mild hypothyroid symptoms are the Zelig of the diagnostic world. They can mimic many conditions and they're often mistaken for signs of menopause, aging or stress.

The list of possible symptoms is as long as the credits of a movie, too. "The fact is, almost any symptom that somebody has could theoretically be related to thyroid," says Gilbert H. Daniels, MD, co-director of Thyroid Associates at Massa-chusetts General Hospital, Boston. Fatigue, weakness, irregular menses, infertility, dry hair, loss of hair, dry skin, coarse skin, hoarse voice, constipation, cold intolerance, depression, mood swings, memory loss, decreased concentration, sore muscles, painful joints, muscle cramps and more--you might have one; you might have many. You may notice nothing at all. In any case, an underactive thyroid can produce so many symptoms that researchers at Johns Hopkins University School of Medicine, Baltimore, are developing a kind of symptom index to sort them out.

But the sneakiest, most serious effect of this mild thyroid failure comes symptom-free: "An elevation of cholesterol is one of the characteristic features of an underactive thyroid gland," says Paul W. Ladenson, MD, director of endocrinology and metabolism at Johns Hopkins University School of Medicine.

It's major stealth, says Lawrence C. Wood, MD, president and medical director of the Thyroid Foun-dation of America, an educational organization in Boston. High cholesterol puts you at risk for atherosclerosis--hardening of the arteries--and heart disease. The Thyroid Foundation estimates that almost 7 million Americans walk around with no idea they have an underactive thyroid that may be hiking their cholesterol and harming their hearts. You don't have to be one of them. Here are Prevention's guidelines for uncovering a balky thyroid--not just after you have symptoms but before they have a chance to make you miserable.
THYROID 101

It's all hormones. People use that popular piece of folk wisdom to explain almost everything that happens in the body. With thyroid hormone, though, it's just about true. The thyroid gland, which looks like a butterfly hugging your windpipe, culls the nutrient iodine out of the bloodstream and makes the hormone thyroxine out of it. Thyroxine seeps into almost every cell of every organ, regulating growth, metabolism, digestion, body temperature and the very beat of our hearts. That's why too little thyroxine (or too much) can produce such a large number of symptoms. But nobody knows for sure what sickens and slows the thyroid. They do know it's an autoimmune disease, like rheu-matoid arthritis or diabetes. Those conditions, for mysterious reasons, cause the body to turn against itself; in the case of the thyroid, it wages war on its own gland.

PHOTO (COLOR): Woman pointing to her thyroid gland

It's not the amount of thyroxine in the bloodstream that first blows the whistle on work. The amount of thyroid-stimulating hormone (TSH) is more telling. That hormone, made by the pituitary gland at the base of the brain, actually directs the production of thyroxine.

When a thyroid starts to fail, the pituitary pumps up the level of TSH to stimulate more hormone production. So a higher than normal level of TSH is the first clue to a slowing thyroid. (A lower than normal level of TSH warns about the opposite disorder--called hyperthyroidism. It's less common than its hypothyroid cousin. And its symptoms, which include jitteriness, sleeplessness and a rapid heartbeat, are usually more obvious.)
CHECKING OUT TSH

Until the 1970s, labs had no way of pinpointing TSH levels precisely. Then the supersensitive TSH test was developed to measure the amount of thyroid-stimulating hormone in the blood. Now physicians who order it can detect even the most furtive case of thyroid dysfunction. But many doctors don't order the test until symptoms rear up and bite their patients. Even then, TSH may be one of the last tests ordered--after all other diagnoses have been discarded. But it's a simple blood test like the cholesterol test. They both can be done from a single blood sample. The TSH test is also less expensive than a mammogram or cholesterol test.

So shouldn't everyone be tested? Shouldn't you be tested? Technically, testing large groups of people even if no symptoms are present is known as screening, and testing only those who do have symptoms is testing. Right now, despite the impact that hypothyroidism can have on people's lives and the relatively low cost of the TSH test, there are no national, generally recognized guidelines for thyroid screening, as there are for cholesterol screening.

Doctors disagree on when and whether to screen people for underlying thyroid disease. The U.S. Preventive Services Task Force does not recommend routine screening for people without symptoms, with a few exceptions. Endocrinologists and thyroid specialists, however, usually recommend screening anyone with certain risk factors. Depending on the professional group or individual physician, the recommended age for initial screening may be 40 or 45 or 50 or at pregnancy or after delivery. Risk factors for mild thyroid failure: being over 50 if you're a woman, being over 60 if you're a man, having a family history of thyroid problems or autoimmune disease, having an autoimmune disease yourself, past treatment with radioactive iodine or radiation to the head or neck, thyroid surgery, and current treatment with certain drugs.

But Prevention goes further than any professional group does in making recommendations for screening. After talking with top thyroid experts and reviewing all available scientific data, we believe that it is in the best interests of all our readers to be screened for thyroid trouble, especially since the screening costs individuals so little and can be so easily combined with cholesterol screening. We don't think any reader should walk around with an underactive thyroid harming her heart, fomenting symptoms or foiling a pregnancy when the problems are readily detected and corrected.
OUR GUIDELINE FOR GENERAL SCREENING

All adults should be screened for mild thyroid failure when they get their cholesterol checked--every 5 years from the age of 20.

Why this sweeping recommendation? Getting both cholesterol and thyroid checked at the same time is simple. The doctor, nurse or technician takes one blood sample and does two tests. The National Cholesterol Education Program (NCEP) recommends that you start screening for cholesterol at the age of 20 and rescreen every 5 years as long as levels are normal. The 5-year schedule works with thyroid screening, too, says Dr. Ladenson. It's a slow-growing disease. And, of course, because the link between high cholesterol and thyroid disease is so strong, it makes even more sense to get your thyroid checked along with your cholesterol, especially if you have high cholesterol.

Screening for thyroid problems early is as reasonable as screening for cholesterol early. The incidence of hypothyroidism rises with age. So the numbers of young people detected with early hypothyroidism wouldn't be huge. But catching the disease before a woman's childbearing is in full swing would thwart the conception problems, low birth weight and miscarriages that a slow thyroid can bring in its wake. Then "by age 35, 5% to 7% of women have mild thyroid dysfunction," says Dr. Ladenson. "That's a large number of women."

There's also the problem of postpartum symptoms. "I think early screening is reasonable in part because it helps predict which women are going to have postpartum thyroid problems," says Dr. Daniels. Childbirth can cause temporary thyroid dysfunction. In about 5% of new mothers, the gland malfunctions. In most mothers, it goes into overdrive, producing too much hormone. Then it may kick back and not produce enough. In the meantime, a mother may suffer what she thinks is postpartum depression. The real problem--postpartum thyroiditis--usually goes away on its own, but for 3 to 6 months a new mother may not be feeling her best when she needs maximum energy. "Somewhere between one-quarter and one-half of mothers who develop postpartum thyroiditis go on to have persistent thyroid dysfunction, too," says Dr. Daniels. "So we're talking about 2% to 3% of women who've ever had a baby. That's a lot."

Finally, we know that many (if not most) physicians favor thyroid testing for people with a family history of thyroid risk factors. That's because such family history is an extremely strong risk factor for thyroid disease. But Prevention recognizes that people often simply don't know their family medical histories. Lots of us just don't know whether Mom or Dad had a sluggish thyroid--or whether Mom's arthritis was rheumatoid (an autoimmune disease) or the osteoarthritis of age. She may not have known herself. So thyroid screening would catch those who simply don't know about their family medical histories.

Your insurance company may not pay for screening (although it will pay for testing if you've already developed symptoms). But for all of the above reasons, Prevention thinks the test is worth the $25 to $50 it costs. And the cost may actually decrease in 2 or 3 years. That's when Franklin Diagnostics in Cedar Knoll, NJ, expects to introduce its $20 home TSH test. Developed by endocrinologist Joel Ehrenkranz, MD, ThyroChek has recently been introduced to primary-care doctors as an office test.
OUR GUIDELINE FOR AT-RISK SCREENING

There are circumstances when you need to speed up screening or testing--if you know for sure Mom was on thyroid hormone, for instance, or if you know your cholesterol's high. These situations suggest that you're at higher risk for thyroid trouble. Here's what those special circumstances are and how often to screen:

You've reached 50 and you're a woman. From three to eight women develop thyroid disease for every one man. By the half-century mark, 10% of American women show elevated TSH levels. When you celebrate that birthday, start checking your TSH levels every 3 years.

You've reached 60 and you're a man. Men aren't immune to thyroid failure. By the time they're 60, 8.7% show high TSH numbers, too. In the thyroid unit at Massachusetts General Hospital, Dr. Wood has treated older folks whose memory loss and lack of concentration had been pinned on dementia or Alz-heimer's disease instead of an underactive thyroid. So men, be sure to schedule a regular screening every 3 years as you hit that significant birthday.

You have a family history of thyroid problems. If you're sure Mom or Dad or Sis was treated for thyroid disease, get your TSH level checked every 3 years no matter what your age. Even if your TSH is normal, your doctor may also test you for the presence of thyroid antibodies--to see if the gland has actually started the process of attacking itself. If you are producing antibodies, you'll probably need to be retested once a year.

You have an autoimmune disease. There are 70 or so autoimmune diseases. Some of the most common are diabetes, rheumatoid arthritis, vitiligo (which leaves white patches on your skin) and premature (before the age of 30) gray hair. If you're diagnosed with such a disorder, ask to have your thyroid checked. Then get a TSH test whenever you have a physical--once every 2 or 3 years.

You were treated with radiation to the head or neck for cancer, or with radioactive iodine for hyperthyroidism, or you had thyroid surgery. Any one of these circumstances may have predisposed you to develop an underactive thyroid gland. In that case, consider having a TSH test done once a year.

You're taking certain drugs. Lithium can do marvels for people with certain forms of depression, especially manic depression. But it also increases thyroid-disease incidence. So does the heart drug amiodarone (Cordarone) and many other drugs containing iodine. If you're taking lithium or amiodarone, be sure your doctor is monitoring your thyroid function with TSH tests 6 weeks after your first treatment, then at 3 months and then once a year.

Your cholesterol is high. A hidden thyroid problem can thwart all your efforts to lower cholesterol with diet and exercise, Dr. Ladenson says. So it's crucial to test for thyroid failure if your numbers are high. Dr. Ladenson uses the NCEP's definition for increased risk: over 200 milligrams/deciliter for total cholesterol and 130 or above for LDL. Prevention advisor William Castelli, MD, medical director of the Fram-ingham Cardiovascular Institute, however, considers a total cholesterol of over 150 as high. Elevated cholesterol levels occur in about 50% of all men and women with severe thyroid failure. "I've been very much surprised by the numbers of hypothyroid patients--3% to 5% of people with lipid disorders--we've found at our clinic," says Dr. Castelli. "We now do routine testing for thyroid failure."

Why a thyroid disorder makes cholesterol rise is only partially understood, says Dr. Ladenson, "Thyroid hormone regulates to some extent how quickly the liver takes cholesterol out of the blood. When there's not enough hormone around, the liver does that less efficiently and your cholesterol rises.

"Most studies have shown that patients with underactive thyroid glands have a level of LDL cholesterol (the so-called bad cholesterol) that's about 30 points higher than it is when their thyroid conditions are corrected," says Dr. Ladenson. That means a 60% increased risk of heart attack, he explains.

If you have high cholesterol and low thyroid function, your thyroid should be treated first, says Dr. Ladenson. "You may not need cholesterol-lowering drugs, with all their side effects and expense, if everything's straightened out with thyroid medication alone, which has no side effects when used in the proper dosage. It's better to get treatment and dedicate yourself to a sensible diet--and then see if your cholesterol is still high or not."
OUR GUIDELINE FOR TESTING

Maybe you've never been tested or screened for thyroid failure. But you've read that list of symptoms and a lightbulb is blinking on. Here are the slipperiest signs of mild hypothyroidism. They can fool you and your doctors alike. If you've been struggling with any of them--seeing lots of doctors and getting no relief--make an appointment to ask your physician for a thyroid check.

You feel tired and depressed. If fatigue and depression have been bothering you for what seems too long a time, don't automatically blame them on menopause or stress. Remember fatigue and depression aren't true medical symptoms of menopause. But they are symptoms of a slow thyroid and serious forms of depression. So in addition to seeing your physican to rule out serious depression, you should have your thyroid tested. If your stress level is high and your thyroid hormone is low, getting the gland treated would very likely make you better able to tackle the stress.

You're having reproductive problems. A slow thyroid can interfere with the brain and pituitary gland's control of the menstrual cycle, says Dr. Ladenson. And that can lead to all kinds of ovulatory trouble--miscarriage, infertility and heavy periods. If any of those problems have been plaguing you, they may be symptoms of low thyroid function. So explore the thyroid connections with your gynecologist.

SOURCES: David Atkins, MD, MPH, senior health-policy analyst, Agency for Health Care Policy and Research, Rockville, MD; William Castelli, MD, Prevention advisor, medical director of the Framingham Cardiovascular Institute, MA; Gilbert H. Daniels, MD, associate professor of medicine, Harvard Medical School, co-director of Thyroid Associates at Massachusetts General Hospital, Boston; Paul W. Ladenson, MD, director of endocrinology and metabolism, Johns Hopkins Medical Institutions; Neil R. Powe, MD, associate professor of medicine, epidemiology and health policy, Johns Hopkins University School of Medicine, Baltimore; Lawrence C. Wood, MD, associate physician, Massachusetts General Hospital, and medical director, Thyroid Foundation of America, Boston, MA.

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By Peggy Morgan

WHEN YOU TAKE A THYROID PILL

If your thyroid gland doesn't put out enough of the hormone thyroxine, your whole system can get put on "snooze." But the condition can be corrected easily with a form of thyroxine--levothyroxine sodium. As drugs go, levothyroxine is pretty benign, although you'll probably need to continue using it for life.

"It's exactly what the body makes," says thyroid expert and Harvard Medical School associate professor Gilbert H. Daniels, MD. "So essentially you can't be allergic to the medicine. Rarely someone has an allergic reaction to the dye in a pill--and then you can prescribe a medicine that doesn't have the dye." Still, if you take a thyroid pill every day, there are a couple of things you should do.

Make sure you get an annual thyroid-stimulating hormone test. You need to monitor your medication to be certain that dosage requirements haven't changed during the year. If you have too much or too little hormone swimming through your bloodstream, your doctor needs to decrease or increase your prescription. The main danger is too much hormone, which can weaken bone or cause serious heart rhythm problems.

Take your thyroid medication at the same time each day and not when you're taking other medicine or vitamins. Some substances can stick to levothyroxine and interfere with its absorption--iron in vitamin pills, for example, and aluminum hydroxide in antacids.

For free information, call the Thyroid Foundation of America at 1-800-832-8321 or write them at Ruth Sleeper Hall 350, 40 Parkman St., Box T, Boston, MA 02114-2698 (include a self-addressed stamped envelope). You can visit their Web site at www.tfaweb.org/pub/tfa.

PHOTOS (COLOR): Woman pressing at the base of her neck

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