Title: Cataracts among Chernobyl clean-up workers: implications regarding permissible eye exposures.
Authors: Worgul, B V; Kundiyev, Y I; Sergiyenko, N M; Chumak, V V; Vitte, P M; Medvedovsky, C; Bakhanova, E V; Junk, A K; Kyrychenko, O Y; Musijachenko, N V; Shylo, S A; Vitte, O P; Xu, S; Xue, X; Shore, R E
Published In Radiat Res, (2007 Feb)
Abstract: The eyes of a prospective cohort of 8,607 Chernobyl clean-up workers (liquidators) were assessed for cataract at 12 and 14 years after exposure. The prevalence of strictly age-related cataracts was low, as expected (only 3.9% had nuclear cataracts at either examination), since 90% of the cohort was younger than 55 years of age at first examination. However, posterior subcapsular or cortical cataracts characteristic of radiation exposure were present in 25% of the subjects. The data for Stage 1 cataracts, and specifically for posterior subcapsular cataracts, revealed a significant dose response. When various cataract end points were analyzed for dose thresholds, the confidence intervals all excluded values greater than 700 mGy. Linear-quadratic dose-response models yielded mostly linear associations, with weak evidence of upward curvature. The findings do not support the ICRP 60 risk guideline assumption of a 5-Gy threshold for "detectable opacities" from protracted exposures but rather point to a dose-effect threshold of under 1 Gy. Thus, given that cataract is the dose-limiting ocular pathology in current eye risk guidelines, revision of the allowable exposure of the human visual system to ionizing radiation should be considered.
PubMed ID: 17390731
MeSH Terms: Adult; Cataract/etiology*; Chernobyl Nuclear Accident*; Cohort Studies; Dose-Response Relationship, Radiation; Eye Injuries/etiology*; Female; Humans; Lens Capsule, Crystalline/radiation effects*; Lens Cortex, Crystalline/radiation effects*; Male; Middle Aged; Nuclear Reactors; Radiation, Ionizing; Risk