April 21, 2000 -- Feeling tired or forgetful? Is your skin and hair drier than normal? Are you retaining water, gaining weight, constipated, or hoarse? These are just a few of the symptoms of a disease called hypothyroidism, which occurs when the thyroid -- a bow tie-shaped gland in the front of the neck -- does not produce enough thyroid hormones.
Low levels of thyroid hormones can cause many problems because the hormones affect nearly every part of the body, such as breaking down fat, regulating menstrual periods, and controlling body temperature.
But you may have low levels of thyroid hormone and not even know it. A recent study in the Archives of Internal Medicine found that nearly 10% of reportedly healthy people whose thyroid function was tested during statewide health fairs in Colorado had low thyroid levels.
"The symptoms of mild hypothyroidism are nonspecific, change gradually, and are easy for a person to write off as the effects of stress or overwork," says study author Gay J. Canaris, MD, MSPH. Canaris is assistant professor of internal medicine at the University of Nebraska Medical Center in Omaha.
The study's results suggest that people are not screened frequently enough for hypothyroidism, and researchers recommend that doctors screen more people for the disease and better educate them about its symptoms.
The basic test to screen for thyroid disease measures the level of thyroid-stimulating hormone (TSH) in the blood. This hormone is extremely sensitive to the body's need for thyroid hormone. When the thyroid is making too little hormone, TSH levels shoot up to try to spur it into action. Therefore, a high TSH level is a sign that all is not well with the thyroid gland.
Thomas C. Rosenthal, MD, says his experience as a family physician has shown him that hypothyroidism can be difficult to recognize.
"[When] I used TSH as part of my routine screening panel, I was surprised to find that many patients had unsuspected hypothyroidism," he says. "These were typically patients who might present with depression ... aches and pains, or concerned about their memory problems." Rosenthal is professor and chair of the department of family medicine at the State University of New York at Buffalo.
Even mild hypothyroidism can cause problems. The Colorado Thyroid Disease Prevalence Study found that people with mild thyroid problems tended to have higher cholesterol and low-density lipoprotein (LDL) levels than those with normal thyroid levels.
The association between low thyroid levels and increased cholesterol and LDL levels worries researchers, because it suggests that hypothyroidism might add to one's risk of heart disease. Both you and your physician should be more aware of the early warning signs so the disease can be diagnosed and treated early.
Canaris recommends regular TSH tests for older patients -- particularly older women -- and for those with a family history of hypothyroidism; those with high cholesterol levels or hypertension; and those with possible symptoms that have changed recently, such as constipation or intolerance to cold. The American Thyroid Association, the American College of Pathology, and the American College of Physicians all recommend regular TSH tests for women over age 50.
- A variety of vague symptoms -- such as fatigue, aches and pains, depression, and memory problems -- could indicate low thyroid function, or hypothyroidism.
- In a recent study, 10% of participants had low thyroid levels, and researchers recommend that certain groups of people get tested regularly, including older patients and those with a family history of hypothyroidism.
- People with low thyroid levels are also more likely to have high cholesterol, suggesting that hypothyroidism may increase the risk of heart disease.