Gaining weight?  Feeling fatigued?  Down in the dumps?  These can all be symptoms of thyroid disease.  Hypothyroidism is more common than you may believe.  Depending on the diagnostic criteria used, hypothyroidism could be affecting anywhere between 5% and 10% of the population.  Many people may have this disease and not even realize it.  According to a study known as the Colorado Thyroid Disease Prevalence Study, there may be as many as 13 million Americans with an undiagnosed thyroid condition. 

To understand thyroid disease, you need to know a little bit about the thyroid gland, an important part of your endocrine system. The thyroid gland is one of the largest endocrine glands.  Dysfunction and distortion of the thyroid gland are among the most common of the endocrine system problems.  Its two lobes look a bit like a butterfly with a "wing" or lobe on each side of your windpipe in the front of your neck connected by a small band of tissue called an isthmus. At just a little over an ounce and a couple of inches side-to-side, it is small but it has a big job.  The thyroid gland has several functions: it forms thyroglobulin, a binding protein; traps, concentrates, and processes iodine; synthesizes and stores thyroid hormone; and releases the hormone as the body needs it. Thyroid hormone helps regulate processes like metabolism (the breakdown of food and its transformation into energy), your body temperature, your heart rate, your blood pressure, and more.  The thyroid gland also secretes thyrocalcitonin, which stimulates the movement of calcium from the bloodstream to the bones.   

An over producing ("hyper") or under producing ("hypo") thyroid impacts every part of your body, including your heart and your brain.  

• Hyperthyroidism:  Excessive amounts of thyroid hormones accelerate body functions and can lead to swelling in the neck (goiter), an increased heart rate or palpitations, anxiety and irritability, tremors, muscle weakness, thinning of the skin, hair loss, osteoporosis, heat intolerance, difficulty sleeping, shorter and lighter menstrual periods, and weight loss despite a strong appetite.
  
  
• Hypothyroidism:  If thyroid hormone levels are too low, body functions can slow down and lead to swelling in the neck (goiter), a slow heart rate, an increase in LDL cholesterol levels, mild anemia, pervasive fatigue, depression, slowed mental functioning, sluggish reflexes, reduced body temperature, cold intolerance, drying and coarsening of the skin, muscle and joint aches, constipation, weight gain in spite of reduced appetite (though only in the range of 5 to 10 pounds), fluid retention, increased sensitivity to many medications, lower libido and other problems with the reproductive system including infertility, increased risk of miscarriage and heavy or irregular menstrual flow in women and erectile dysfunction in men, low sperm count, slow wound healing, easy bruising, slowed hair growth, obstructive sleep apnea, constipation, gas distension of the abdomen, stiff aching muscles worsened by cold.

The most common form of thyroid disease is hypothyroidism (also called underactive thyroid disease).  99% of hypothyroidism is due to a permanent loss of the thyroid gland's ability to make enough thyroid hormone and is known as primary hypothyroidism.  Other reasons for hypothyroidism, transient or permanent, are rare.  Diagnosis is done with simple blood tests but there are some wrinkles.  The symptoms of hypothyroidism may appear gradually, often over months or years, making them easy to overlook by the patient, family, and friends.  They can also mimic other conditions, especially those normally associated with menopause and advancing age.  Finally, there are no commonly accepted guidelines for screening.  Because women are 5 to 8 times more likely than men to suffer from a thyroid condition¹ and its incidence increases with age, the American College of Physicians (ACP) recommends hypothyroid screening for women over 50.  The American Thyroid Association recommends screening for women every five years beginning at age 35.  Many doctors recommend automatic screening for pregnant women or women thinking of becoming pregnant and annual checks for people with a family history of autoimmune disease.

Once hypothyroidism is diagnosed, treatment by replacing the missing thyroid hormone is usually very successful.  It can be a long process to establish the proper dosage, but once that's achieved, patients generally begin to feel like they did before becoming hypothyroid. 

¹ Wood L.C. "Your Thyroid: A Home Reference," Ballantine Books, New York, 1995 (pp. 216-217).


Learn more about Hypothyroidism:

Key Point 1: The thyroid gland is a critical part of your body's regulatory system and affects your physical and mental health.  Symptoms caused by too little or too much thyroid hormone can greatly affect your daily life. 

Key Point 2:  Hypothyroidism is treated by replacing the thyroid hormone that the body is not producing.  Untreated hypothyroidism and over-treated hypothyroidism can be harmful.