Hyperparathyroidism following head and neck irradiation.

A history of head and neck irradiation in childhood or adolescence was found in 22 of 130 patients with primary hyperparathyroidism compared with only 12 of 400 control patients, a significant difference (P less than .025). Among 200 patients with a known history of childhood irradiation, biochemical or surgical evidence of hyperparathyroidism was found in ten, a prevalence of 5%. This is at least 30 times the prevalence of hyperparathyroidism in the general population (P less than .025). The data indicate that head and neck irradiation should be regarded as an important risk factor in the subsequent development of hyperparathyroidism.