Hyperparathyroidism and thyroid disease. A study of their association.

The incidence of hyperparathyroidism was prospectively evaluated in a group of patients with thyroid disease, and the incidence of thyroid disease was retrospectively evaluated in a group of patients specifically referred for evaluation of hyperparathyroidism. Hyperparathyroidism was ten times more frequent in thyroid patients than expected in a general medical population and was especially prevalent in patients with nodular goiter. The incidence of thyroid disease in patients with hyperparathyroidism was 38.8%. Although radiation therapy was shown to be a factor in these associations, it alone could not explain the observed frequency.