Weighs less than an ounce, but it's essential to your life.
Olympic track star Gail Devers suffered from it. So did former First Lady Barbara Bush, who confided to the press at the time that her gland "went whacko." George Bush, too, was afflicted, rushed to the hospital in 1991 when his heart started racing.
Their problem? Thyroid disorders.
The thyroid gland, located just below your Adam's apple, weighs less than an ounce, but it's essential to most of your body's functioning. The gland takes dietary iodine from your blood and uses it to make two hormones that influence heart rate, body weight, mood, energy, skin condition, and, if you're a woman, fertility and menstrual regularity.
Properly treated, thyroid problems can be managed relatively easily. But, first they must be detected -- which isn't always easy.
The most common thyroid problem is hypothyroidism ("hypo" means too low), which occurs when the gland produces too little hormone. Eleven million Americans have this condition, according to the Thyroid Foundation of America. Untreated, hypothyroidism can cause high cholesterol, forgetfulness, difficulty concentrating, and infertility.
If your gland is underactive, it causes a slowdown in your metabolism. You may feel tired and sluggish. You may gain weight (usually no more than 10 or 20 pounds) or be sensitive to the cold. Other symptoms include a puffy face, dry skin, brittle nails, constipation, or irregular menstrual periods.
For most sufferers, thyroid troubles develop gradually over many months and may be overlooked or attributed to stress, normal aging, or menopause. Studies suggest that half the people who are hypothyroid aren't aware of it, says Loren Wiser Greene, M.D., an endocrinologist at the New York University School of medicine.
"People just think they're getting older or feeling depressed," says Dr. Greene. "Even family members and close friends often don't notice changes."
The most common cause of hypothyroidism is Hashimoto's disease, a disorder in which the immune system produces cells that attack the thyroid. It is five to eight times more common in women than in men, and usually occurs after 40. By 60, an estimated 17 percent of women and 9 percent of men have an underachieve thyroid. Your risk rises if you have a family history of thyroid disease or an autoimmune disease, such as diabetes.
About one in 20 women experiences thyroid problems after giving birth. New mothers may first develop the "hyped-up" symptoms of an overactive thyroid, then have their thyroid plunge too low and develop postpartum depressionlike symptoms, says Dr. Greene. Often, hormone production returns to normal a year after birth, but short-term treatment is sometimes needed, she says.
Thyroid disorders can be easily uncovered with a highly sensitive blood test that measures thyroid-stimulating hormone (TSH), a substance secreted by the pituitary gland. The pituitary regulates how much hormone is produced by the thyroid gland. When the thyroid is underactive, it registers high levels; when the gland is overstimulated, it's low.
The sensitive TSH test makes early diagnosis possible, allowing patients to start treatment before troublesome symptoms develop. The test -- which costs about $50 -- isn't routine in regular health exams, but some medical experts believe it should be. A study published last year in The Journal of the American Medical Association reported that regular testing of men and women 35 years and older for thyroid problems would be as cost-effective as checking blood pressure or testing cholesterol levels.
The American Association of Clinical Endocrinologists (AACE) urges older adults, especially older women, to have regular thyroid tests even if they don't have symptoms. AACE doesn't specify at what age. Experts disagree over guidelines, says Stanley Feld, M.D., a Dallas endocrinologist. "Some experts think mass screening should start at 60, but if you're a 33-year old woman with unexplained symptoms, you should get tested."
Once it's diagnosed, doctors treat hypothyroidism by replacing the flagging thyroid hormone with a synthetic version called levothyroxine, sold as Synthroid, Levothroid, or Levoxyl. The medication restores hormone levels to normal and eliminates symptoms. Typically, it delivers benefits within weeks, but it often takes a few months and some experimentation to find the correct dose.
The drug is not a cure. It must be taken daily for life. Fortunately, it has few side effects or allergies, can be taken during pregnancy or nursing, and is inexpensive (about $60 to $80 a year).
If you're taking the pill, be sure to have periodic TSH blood tests to ensure the correct dose, says Lawrence Wood, M.D., the Thyroid Foundation of America's medical director. Too-high thyroid levels can cause bone loss, increasing the risk for osteoporosis and heart problems.
Graves' disease, the most common cause of hyperthyroidism, happens when the thyroid produces too much hormone. Like hypothyroidism, it tends to run in families with thyroid problems or autoimmune diseases. It's more prevalent in women than men, particularly those in their thirties and forties.
If you're hyperthyroid ("hyper" indicates too much), you're likely to suffer rapid heart beat, muscle tremors, weight loss, anxiety, or irritability. Other signs are menstrual irregularities, hair loss, heat intolerance, vision problems, and/or an enlarged thyroid. In the elderly, symptoms are often subtle. "Weight loss and muscle weakness might be the only symptoms," says Dr. Wood.
Graves' disease sometimes is accompanied by eye problems, caused by antibodies that attack tissue behind the eyes. Burning, dryness, and double vision can result. Sometimes, the tissues swell, causing the eyes to bulge. Doctors use the TSH blood test to diagnose hyperthyroidism, then may follow up with tests that directly measure thyroid hormone to assess the severity of the problem.
Two common treatment options are radioactive iodine therapy and medication. Surgery is a third choice but is rarely done in the U.S. It is reserved for the few patients who aren't suitable candidates for the first two, says David Cooper, M.D., director of the Thyroid Clinic at Johns Hopkins University.
Antithyroid medications, such as methimazole and propylthiouricil, block hormone production. These drugs can deliver relief within weeks or a few months. Usually, they are taken for one year or longer then discontinued. In about 30 percent of cases, the condition goes into remission and drug therapy is stopped, says Dr. Cooper.
These medications, however, sometimes cause unpleasant side effects, such as rashes and liver problems. Radioiodine therapy has emerged as the most common treatment. Taken in the form of a drink or a pill, radioactive iodine collects in the thyroid, where it irradiates cells and disables the gland. The iodine is quickly excreted and doesn't harm other organs, says Dr. Cooper.
An estimated 30 million Americans have a lump in their thyroid called a nodule. Most nodules are harmless, but in 5 to 10 percent of cases, these growths are cancerous, says Dr. Feld.
The causes of thyroid cancer are unclear, but people who've had X-ray treatment to their thymus gland as children are at higher risk.
Diagnosis for thyroid cancer is done by fine needle aspiration biopsy. A doctor inserts a needle into the nodule to extract a tissue sample. Fortunately, treatment has a high success rate.
A new, simple self-exam can help detect thyroid cancer. The test, created by the American Association of Clinical Endocrinologists, detects a nodule, a lump in the thyroid gland, or a goiter, an enlarged gland. To take the test, you'll need a handheld mirror and a glass of water.
1. Holding the mirror in your hand, look at the area of your neck where your thyroid gland is located -- just below the Adam's apple and immediately above the collarbone.
2. Tip your head back.
3. Take a drink of water and swallow.
4. As you swallow, look at your neck and check for any bulges or protrusions. (Don't confuse your thyroid for your Adam's apple.) Repeat the process several times.
5. If you notice any bulges or protrusions, call your doctor immediately.