By some estimates, 10 to 15 percent of middle-aged and older individuals have "subclinical" hypothyroidism. Across all age groups, 4 percent of the U.S. population is affected. The term subclinical means that there are no obvious symptoms, though some people may have fatigue, depression, dry skin, cold intolerance, weight gain, memory loss, and other hypothyroidism symptoms.
Two studies published in the Archives of Internal Medicine show that people with low thyroid activity, even at the subclinical level, are elevated risk for heart disease. While neither study actually proves that thyroid dysfunction causes heart disease, this is another reason to have a thyroid test, especially if you are older and even more so if you are a woman. A simple blood test can measure thyroid activity level.
