THE CURRENT STATUS OF CHORNOBYL CATASTROPHE VICTIMS' COHORTS AND EXPERIENCE OF MEDICAL EXPERTISE FOR ESTABLISH CAUSATION OF DISEASE, LEADING TO LOSS OF HEALTH, DISABILITY AND DEATH WITH THE ACTION OF IONIZING RADIATION AND OTHER HARMFUL FACTORS OF THE CHORNOBYL NPP ACCIDENT.

INTRODUCTION: Nearly four decades after the Chornobyl Nuclear Power Plant accident, its medical and social consequences continue to require systematic evaluation, particularly in the context of formal medical expertise aimed atcertifying causal relationships between disease outcomes and radiation exposure associated with the accident. In theremote postaccidental period, medical expertise plays a central role within the national system of social protection,providing legally substantiated conclusions on health loss, disability, and causes of death among affected population.

OBJECTIVE: to study and characterize the number and structure of affected population categories (cleanup workersand victims) based on materials from the National Social Service of Ukraine Register and expert cases of the CentralInterdepartmental Expert Commission of the Ministry of Health of Ukraine (CIEC) in the remote postaccidental period.

METHODS: A retrospective study was conducted using data from the National Social Service of Ukraine Register(2008-2025) and materials from medical expert cases reviewed by the Central Interdepartmental Expert Commissionof the Ministry of Health of Ukraine during 2023-2025. Expert documentation was analyzed using a systematicapproach, including verification of diagnoses and assessment of medical and nonmedical parameters in accordancewith current regulatory requirements. Descriptive analytical methods were applied.

RESULTS: The affected population demonstrated a sustained longterm decline, primarily reflecting cohort ageingand administrative status changes. Despite this reduction, the volume of medical expertise activity remained substantial. Oncological diseases constituted the predominant category of expert assessments, followed by severechronic nononcological conditions, mainly cerebrovascular and cardiovascular diseases with complications.Distinct differences were observed between lifetime and postmortem expert assessments, reflecting variations indisease severity, clinical course, and fatal outcomes rather than populationlevel disease patterns.

CONCLUSIONS: In the remote postaccidental period, medical expert assessments related to the Chornobyl accidentcontinue to be dominated by malignant neoplasms and advanced chronic diseases of circulatory system leading tosignificant loss of health, increasing disability and mortality. Expertbased data provide a specific and complementary perspective on the enduring medical and social consequences of the accident and remain essential for informeddecisionmaking within the national system of health protection and social support.