Prevalence and Impact of Thyroid Disease More than 12 percent of the U.S. population will develop a thyroid condition during their lifetime. •An estimated 20 million Americans have some form of thyroid disease. •Up to 60 percent of those with thyroid disease are unaware of their condition. •Women are five to eight times more likely than men to have thyroid problems. •One woman in eight will develop a thyroid disorder during her lifetime. •Most thyroid cancers respond to treatment, although a small percentage can be very aggressive. •The causes of thyroid problems are largely unknown. •Undiagnosed thyroid disease may put patients at risk for certain serious conditions, such as cardiovascular diseases, osteoporosis and infertility. •Pregnant women with undiagnosed or inadequately treated hypothyroidism have an increased risk of miscarriage, preterm delivery, and severe developmental problems in their children. •Most thyroid diseases are life-long conditions that can be managed with medical attention.