Excess Relative Risk of Cataractogenic Lense Disordes in Nuclear Workers: Systematic Review and Meta-analysis

Abstract

The lens cells are the most radiosensitive cells in the body, surpassing even lymphocytes in key parameters. Radiation damages in the lens can be observed at relatively low doses, in connection with which a number of authors attribute to these effects not a deterministic, but a stochastic nature. Although cataractogenic consequences do not always affect visual acuity, and lens undergo successful surgical correction, when irradiating various professional groups, including workers in the nuclear industry, these consequences are regarded in importance immediately after malignant neoplasms and diseases of the circulatory system. The presented study showed that there are very few publications on the lens disorders in nuclear workers – only 20 sources were identified (1967–2022), and no data were found on the effects of low doses (0.1 Gy for low LET radiation). When conducting a meta-analysis for ERR at 1 Gy/Sv for radiation damage in the lens of nuclear workers, three cohorts turned out to be relevant: a small group in the American study of transuranium elements processing, Mayak personnel and ROSATOM workers – liquidators of the Chernobyl accident. The sample was homogeneous, publication bias was unlikely, and, according to the results of a meta-analysis (Fixed effect model), ERR per 1 Gy/Sv was 0.30 (95 % confidence intervals: 0.25; 0.35). Based on the earlier work (Koterov A.N. et al, 2022) of the mean cumulative dose of external exposure for nuclear workers as a world professional category, which amounted to 31.1 mSv, the calculation showed that with ERR = 0.3 per 1 Gy/Sv excess prevalence of cataracts for a group of ‘average’ workers is 0.0093. This corresponds to an increase in prevalence of 0.096 % over a background level of 10.3 % for potentially radiogenic cataracts (last value taken from a meta analysis by Hashemi H. et al., 2020). Such an increase is unlikely to have practical significance. Although for some cohorts (Sellafield, PO ‘Mayak’) there may be groups with significant cumulative doses and, therefore, with increased risks. The importance of the risks of cataractogenic disorders in the lens in radiation workers may be due to a decrease in professional suitability, since the artificial lens, as a rule, is poorly capable of accommodation.