Data on the risks of subclinical hypothyroidism are limited. Rodondi and colleagues examined the risks of heart failure, coronary heart disease, stroke, peripheral arterial disease, and death in relationship to thyrotropin (TSH) levels in a prospective cohort of 2730 older adults. Compared with euthyroid participants, older adults with a TSH level of 7.0 mIU/L or greater had a 2- to 3-fold increased risk of congestive heart failure events. Both incident and recurrent heart failure events were increased in this group. Heart failure events were not increased among those with TSH levels between 4.5 and 6.9 mIU/L. Subclinical hypothyroidism was not associated with increased risk for coronary heart disease, stroke, peripheral arterial disease, or cardiovascular or total mortality.