Worldwide about one billion people are estimated to be iodine deficient; however, it is unknown how often this results in<unk> . In large population-based studies in Western countries with sufficient dietary iodine, 0.3–0.4% of the population have overt<unk> . A larger proportion, 4.3–8.5%, have subclinical<unk> . Of people with subclinical<unk> , 80% have a TSH level below the 10 mIU/l mark regarded as the threshold for treatment. Children with subclinical<unk>  often return to normal thyroid function, and a small proportion develops overt<unk>  (as predicted by evolving antibody and TSH levels, the presence of celiac disease, and the presence of a goiter). Women are more likely to develop<unk>  than men. In population-based studies, women were seven times more likely than men to have TSH levels above 10 mU/l. 2–4% of people with subclinical<unk>  will progress to overt<unk>  each year. The risk is higher in those with antibodies against thyroid peroxidase. Subclinical<unk>  is estimated to affect approximately 2% of children; in adults, subclinical<unk>  is more common in the elderly, and in Caucasians. There is a much higher rate of thyroid disorders, the most common of which is<unk> , in individuals with Down syndrome and Turner syndrome. Very severe<unk>  and myxedema coma are rare, with it estimated to occur in 0.22 per million people a year. The majority of cases occur in women over 60 years of age, although it may happen in all age groups. Most<unk>  is primary in nature. Central/secondary<unk>  affects 1:20,000 to 1:80,000 of the population, or about one out of every thousand people with<unk> .
Hypothyroidism
Heart failure
Late onset congenital adrenal hyperplasia
Dementia
Autoimmune thyroiditis
Depression (mood)
Acromegaly
Chronic fatigue syndrome