Hyperparathyroidism subsequent to neck irradiation. Risk factors.

A follow-up examination of 444 persons treated with x-rays for tuberculous cervical adenitis was performed to determine if the risk for hyperparathyroidism (HPT) following radiation exposure can be related to the age at treatment, the dose of x-rays, or the sex of the patient. The overall incidence of HPT was 14%. There was no definite age-dependent difference in susceptibility to the induction of HPT. The doses of radiation among the 63 subjects who developed HPT ranged from 0.6 to 45.7 Gy (60-4570 rad). There was a statistically significant positive correlation between the dose of radiation and the probability of developing HPT. After doses of 14 Gy (1400 rad) or more 29% of the subjects had developed HPT. After neck irradiation women had twice the relative risk of men of developing HPT. This sex ratio was lower than in the series of nonirradiated HPT patients treated at the same institution during the time of the follow-up study.