Low awareness and under-diagnosis of hypothyroidism

Hypothyroidism is a common condition with a prevalence that varies according to local dietary iodine availability, gender and age. The symptoms of hypothyroidism are generally nonspecific, with considerable overlap with other conditions and with the consequences for the health of advancing age. These symptoms are not useful for diagnosing hypothyroidism and a thyroid function test is required for a firm clinical diagnosis. Lack of knowledge and understanding of hypothyroidism, and a tendency for many people to attribute the symptoms of hypothyroidism to other causes have led to substantial unawareness and often late diagnosis of hypothyroidism. Large observational studies and meta-analyses have shown that about 4-7% of community-derived populations in the USA and Europe have undiagnosed hypothyroidism. About four cases in five of these are subclinical hypothyroidism, with the remainder being overt hypothyroidism. The prevalence of undiagnosed hypothyroidism is higher in older subjects, in women, and some ethnic groups, consistent with diagnosed disease. More research is needed to quantify the clinical burden of undiagnosed hypothyroidism around the world, with educational efforts aimed at the public and healthcare professionals aimed at identifying and managing these individuals.