Health Impacts of Chronic Radiation Exposure in Northern Kazakhstan: A Comprehensive Epidemiological Review.

Chronic exposure to ionizing radiation from uranium legacy sites remains a significant public health concern in Northern Kazakhstan. This review evaluates epidemiological, clinical, and environmental evidence published between 2000 and 2025, with particular emphasis on studies conducted during 2014-2023 in the Stepnogorsk region among populations residing near former uranium mining sites. Residents were exposed to annual external gamma doses of approximately 1.0-3.5 mSv and radon-related doses of up to 1.2 mSv. Cancer registry analyses revealed 1913 malignancy cases in the exposed group (vs. 358 controls), with digestive (29%) and respiratory (17%) cancers predominating. Early signs of chronic radiation syndrome (CRS) were consistently observed, including olfactory dysfunction, immunosuppression, vestibular disturbances, hematologic anomalies, and elevated chromosomal aberrations (1.3-1.5× baseline). Non-cancer morbidity was also elevated, including hypertension (32% vs. 24%), chronic bronchitis (14% vs. 8%), and reduced forced expiratory volume in one second (FEV1; -9.7%), indicating broader systemic effects. These results underscore the need for targeted public health strategies incorporating CRS biomarker screening, cancer surveillance, personal dosimetry, and environmental remediation in uranium-impacted communities.