Risk of cataract of different morphological types in Urals population chronically exposed at low doses

Objective

To assess the risk of lens opacity depending on the dose in the population exposed to external and internal radiation for a long time, based on a long-term clinical follow-up of the cohorts of people exposed to radiation as a result of two radiation accidents in the South Urals.

Methods

A layer-by-layer morphological study of the lens of 1,377 exposed individuals was conducted according to a special program in the Clinical Department of the Urals Research Center for Radiation Medicine (URCRM) 68 years after the onset of exposure. Lens changes were classified in accordance with the lens opacities classification (LOCS) III and included images of lens. To calculate the doses to lens, the data were taken into account, including the person's residence history in the radioactively contaminated territory, age and sex that affected their lifestyle and diet, radionuclide distribution in organs and tissues. Individualized lens doses were calculated using Techa River Dosimetry System (TRDS)-2016. Case-control method was used for statistical analysis.

Results

Individual values of absorbed dose to lens ranged from 0 to 600 ​mGy. A dose-dependent increased risk of posterior subcapsular cataract (PSC) (OR ​1.54, 95%CI: 1.04–2.27) and nuclear cataract (OR ​1.84, 95%CI: 1.14–2.95) was found among chronically exposed individuals by a case-control method. No evidence of dose effect was found for cortical cataracts.

Conclusions

The results showed that population exposed to long-term chronic low-dose radiation was subjected to an increased risk of PSC and nuclear cataract development.