Should subclinical hyperthyroidism be treated? If so, when?

Here are some key points from the ATA guidelines:

When TSH is persistently less than 0.1 mU/L, treatment of SH is recommended in all individuals greater than or equal to 65 years of age; in patients with cardiac risk factors, heart disease or osteoporosis; in postmenopausal women who are not on estrogens or bisphosphonates; and in individuals with hyperthyroid symptoms…

When TSH is persistently less than 0.1 mU/L, treatment of SH should be considered in asymptomatic individuals less than 65 years of age without the risk factors listed in Recommendation 73...

When TSH is persistently below the lower limit of normal but greater than or equal to 0.1 mU/L, treatment of SH should be considered in individuals greater than or equal to 65 years of age and in patients with cardiac disease, osteoporosis, or symptoms of hyperthyroidism…

When TSH is persistently below the lower limit of normal but greater than or equal to 0.1 mU/L, asymptomatic patients under age 65 without cardiac disease or osteoporosis can be observed without further investigation of the etiology of the subnormal TSH or treatment.