Occupational radiation exposure and risk of cataract incidence in a cohort of US radiologic technologists

Eur J Epidemiol. 2018 Dec;33(12):1179-1191. doi: 10.1007/s10654-018-0435-3. Epub 2018 Aug 27.

Abstract

It has long been known that relatively high-dose ionising radiation exposure (> 1 Gy) can induce cataract, but there has been no evidence that this occurs at low doses (< 100 mGy). To assess low-dose risk, participants from the US Radiologic Technologists Study, a large, prospective cohort, were followed from date of mailed questionnaire survey completed during 1994-1998 to the earliest of self-reported diagnosis of cataract/cataract surgery, cancer other than non-melanoma skin, or date of last survey (up to end 2014). Cox proportional hazards models with age as timescale were used, adjusted for a priori selected cataract risk factors (diabetes, body mass index, smoking history, race, sex, birth year, cumulative UVB radiant exposure). 12,336 out of 67,246 eligible technologists reported a history of diagnosis of cataract during 832,479 person years of follow-up, and 5509 from 67,709 eligible technologists reported undergoing cataract surgery with 888,420 person years of follow-up. The mean cumulative estimated 5-year lagged eye-lens absorbed dose from occupational radiation exposures was 55.7 mGy (interquartile range 23.6-69.0 mGy). Five-year lagged occupational radiation exposure was strongly associated with self-reported cataract, with an excess hazard ratio/mGy of 0.69 × 10-3 (95% CI 0.27 × 10-3 to 1.16 × 10-3, p < 0.001). Cataract risk remained statistically significant (p = 0.030) when analysis was restricted to < 100 mGy cumulative occupational radiation exposure to the eye lens. A non-significantly increased excess hazard ratio/mGy of 0.34 × 10-3 (95% CI - 0.19 × 10-3 to 0.97 × 10-3, p = 0.221) was observed for cataract surgery. Our results suggest that there is excess risk for cataract associated with radiation exposure from low-dose and low dose-rate occupational exposures.

Keywords: Cataract; Cataract surgery; Diabetes; Ionising radiation; Low dose rate; Questionnaire-based assessment; Threshold; Tissue reaction effects.

MeSH terms

  • Adult
  • Allied Health Personnel* / statistics & numerical data
  • Cataract / epidemiology
  • Cataract / etiology*
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Occupational Diseases / epidemiology*
  • Occupational Diseases / etiology
  • Occupational Exposure / adverse effects*
  • Occupational Exposure / analysis
  • Radiation Exposure / adverse effects*
  • Radiation Exposure / statistics & numerical data
  • Risk Factors
  • Technology, Radiologic / statistics & numerical data
  • United States
  • Young Adult