Researchers estimate that between 2-4/1,000 people worldwide have previously undiagnosed, spontaneous overt hypothyroidism. Prevalence increases to about 10/1,000 if the following are added to these numbers: every previously diagnosed case, radioiodine treatment cases, and thyroid surgeries. Finally, upon adding in subclinical cases, the prevalence increases substantially, to more than 50/1,000 for the total population.
For cisgender females, the annual rate of overt hypothyroidism falls between 1-2/1,000. Conversely, for cisgender males, the incidence is only 2/10,000.