CLINICAL ANALYSIS OF THE FREQUENCY OF PARATHYROID HYPERPLASIA AND HYPERPARATHYROIDISM IN THE CHORNOBYL NPP ACCIDENT...

the scientific analysis of the frequency of structural and functional changes in parathyroid glands (PTH)in different categories of the Chornobyl NPP (ChNPP) accident survivors (i.e. the irradiated individuals).

The prospective study of 815 individuals and retrospective analysis of 3,849 case records(total 4,664 individuals) aged 19-75 years at the time of survey, in the range of 0.05-0.2 Gy external radiation dosesamong the ChNPP accident cleanup workers, was performed. Anthropometric, laboratory (parathyroid hormone,vitamin D, calcium, phosphorus, thyroid hormones, thyroid antibodies, and biochemical assays), instrumental (thyroid and parathyroid diagnostic ultrasound) and statistical methods were applied.

There was a higher incidence of the ultrasound signs of parathyroid hyperplasia in the ChNPP accident survivors compared to controls (pooled RR ≈ 1.43; p < 0.001), with the highest values among evacuees and cleanupworkers workers. Incidence of nonrenal normocalcemic hyperparathyroidism (NRHPT) featured a trend to increasein survivors (RR ≈ 1.35; p ≈ 0.095) increasing with age. Level of parathyroid hormone was higher in females than inmales. Increase in the proportion of NRHPT was noted in the period 2019-2024 in both groups with more theincrease in survivors (slope difference ≈ +0.75 p.p./year; p ≈ 0.03). In subgroups of persons with comorbidities theproportion of NRHPT was higher in survivors, however not reaching a statistical significance in the study sample(crude estimates; p > 0.3).

The radiation factor of the ChNPP accident is associated with an increased risk of structural and functional parathyroid changes and normocalcemic NRHPT in particular. There is a higher incidence of ultrasound signsof parathyroid hyperplasia in the ChNPP accident survivors, especially the evacuees and local residents, than in subjects not exposed to extra exposure to ionizing radiation in their daily or practical activities (RR ≈ 1.43; p < 0.001).