Risk of Cataract after Exposure to Low Doses of Ionizing Radiation: A 20-Year Prospective Cohort Study among US Radiologic Technologists

Abstract

The study aim was to determine the risk of cataract among radiologic technologists with respect to occupational and nonoccupational exposures to ionizing radiation and to personal characteristics. A prospective cohort of 35,705 cataract-free US radiologic technologists aged 24-44 years was followed for nearly 20 years (1983-2004) by using two follow-up questionnaires. During the study period, 2,382 cataracts and 647 cataract extractions were reported. Cigarette smoking for >or=5 pack-years; body mass index of >or=25 kg/m(2); and history of diabetes, hypertension, hypercholesterolemia, or arthritis at baseline were significantly (p <or= 0.05) associated with increased risk of cataract. In multivariate models, self-report of >or=3 x-rays to the face/neck was associated with a hazard ratio of cataract of 1.25 (95% confidence interval: 1.06, 1.47). For workers in the highest category (mean, 60 mGy) versus lowest category (mean, 5 mGy) of occupational dose to the lens of the eye, the adjusted hazard ratio of cataract was 1.18 (95% confidence interval: 0.99, 1.40). Findings challenge the National Council on Radiation Protection and International Commission on Radiological Protection assumptions that the lowest cumulative ionizing radiation dose to the lens of the eye that can produce a progressive cataract is approximately 2 Gy, and they support the hypothesis that the lowest cataractogenic dose in humans is substantially less than previously thought.

Protracted low-dose radiation exposure and cataract in a cohort of Chinese industry radiographers

“…Protracted exposures to low levels of photon radiation was, therefore, found to be a risk factor for the development of cortical and PSC opacities, although dose–effect relationships were not observed for these types of cataracts. Our results are consistent with findings from previous studies, including the Chernobyl liquidators,6 US astronauts,12 atomic bomb survivors,21 commercial airline pilots,22 healthcare personnel7 and Taiwanese living in 60 Co-contaminated steel 23. All of these studies found a significant association between protracted exposure to low-dose radiation, and increased risk of cortical and PSC cataract formation or other lenticular changes.…”

“…The average individual cumulative dose among industrial radiography workers was 38.8 mSv. This is low compared to the average dose in previous studies4–6 and the ICRP dose limit,6 except for those in the 20-year prospective cohort study of US radiological technologists (average 28.1 mSv) 7. Thus, we suggest that the likelihood of cataract formation increases with increasing protracted exposure to ionising radiation, with no apparent threshold level.…”

Protracted low-dose radiation exposure and cataract in a cohort of Chinese industry radiographers

“…Protracted exposures to low levels of photon radiation was, therefore, found to be a risk factor for the development of cortical and PSC opacities, although dose–effect relationships were not observed for these types of cataracts. Our results are consistent with findings from previous studies, including the Chernobyl liquidators,6 US astronauts,12 atomic bomb survivors,21 commercial airline pilots,22 healthcare personnel7 and Taiwanese living in 60 Co-contaminated steel 23. All of these studies found a significant association between protracted exposure to low-dose radiation, and increased risk of cortical and PSC cataract formation or other lenticular changes.…”

“…The average individual cumulative dose among industrial radiography workers was 38.8 mSv. This is low compared to the average dose in previous studies4–6 and the ICRP dose limit,6 except for those in the 20-year prospective cohort study of US radiological technologists (average 28.1 mSv) 7. Thus, we suggest that the likelihood of cataract formation increases with increasing protracted exposure to ionising radiation, with no apparent threshold level.…”

Risk of Cataract Incidence in a Cohort of Mayak PA Workers following Chronic Occupational Radiation Exposure

“…ERRs/Gy in the Adult Health Study were 1.3 (95% CIs: 1.1, 1.5) for surgically removed cataracts [ 24 ] and 1.06 (95% CIs: 1.01, 1.11) for total cataracts [ 7 ]. The risk estimated for cataract incidence in the present study was markedly lower than those reported for the cohort of Chernobyl clean-up workers which was 1.6 (95% CIs: 1.2, 2.3) [ 6 ] and found for surgically removed cataracts in the US radiologists which was 2.5 (95% CIs: <1.07, 7.4) [ 25 ].…”

Dose reduction in computed tomography: the effect of eye and testicle shielding on radiation dose measured in patients with beryllium oxide-based optically stimulated luminescence dosimetry

“…Artifacts seem to be of minor importance for orbital shielding [7,9], or may be avoidable if the eye shield is placed properly [11]. Our results and recent data on the substantial radiation sensitivity of the lens [4] support the recommendation for subsequent usage of orbital shielding.…”

Protracted low-dose radiation exposure and cataract in a cohort of Chinese industry radiographers

“…Protracted exposures to low levels of photon radiation was, therefore, found to be a risk factor for the development of cortical and PSC opacities, although dose–effect relationships were not observed for these types of cataracts. Our results are consistent with findings from previous studies, including the Chernobyl liquidators,6 US astronauts,12 atomic bomb survivors,21 commercial airline pilots,22 healthcare personnel7 and Taiwanese living in 60 Co-contaminated steel 23. All of these studies found a significant association between protracted exposure to low-dose radiation, and increased risk of cortical and PSC cataract formation or other lenticular changes.…”

“…The average individual cumulative dose among industrial radiography workers was 38.8 mSv. This is low compared to the average dose in previous studies4–6 and the ICRP dose limit,6 except for those in the 20-year prospective cohort study of US radiological technologists (average 28.1 mSv) 7. Thus, we suggest that the likelihood of cataract formation increases with increasing protracted exposure to ionising radiation, with no apparent threshold level.…”

Risk of Cataract Incidence in a Cohort of Mayak PA Workers following Chronic Occupational Radiation Exposure

“…ERRs/Gy in the Adult Health Study were 1.3 (95% CIs: 1.1, 1.5) for surgically removed cataracts [ 24 ] and 1.06 (95% CIs: 1.01, 1.11) for total cataracts [ 7 ]. The risk estimated for cataract incidence in the present study was markedly lower than those reported for the cohort of Chernobyl clean-up workers which was 1.6 (95% CIs: 1.2, 2.3) [ 6 ] and found for surgically removed cataracts in the US radiologists which was 2.5 (95% CIs: <1.07, 7.4) [ 25 ].…”

Dose reduction in computed tomography: the effect of eye and testicle shielding on radiation dose measured in patients with beryllium oxide-based optically stimulated luminescence dosimetry

“…Artifacts seem to be of minor importance for orbital shielding [7,9], or may be avoidable if the eye shield is placed properly [11]. Our results and recent data on the substantial radiation sensitivity of the lens [4] support the recommendation for subsequent usage of orbital shielding.…”

Protracted low-dose radiation exposure and cataract in a cohort of Chinese industry radiographers

“…Protracted exposures to low levels of photon radiation was, therefore, found to be a risk factor for the development of cortical and PSC opacities, although dose–effect relationships were not observed for these types of cataracts. Our results are consistent with findings from previous studies, including the Chernobyl liquidators,6 US astronauts,12 atomic bomb survivors,21 commercial airline pilots,22 healthcare personnel7 and Taiwanese living in 60 Co-contaminated steel 23. All of these studies found a significant association between protracted exposure to low-dose radiation, and increased risk of cortical and PSC cataract formation or other lenticular changes.…”

“…The average individual cumulative dose among industrial radiography workers was 38.8 mSv. This is low compared to the average dose in previous studies4–6 and the ICRP dose limit,6 except for those in the 20-year prospective cohort study of US radiological technologists (average 28.1 mSv) 7. Thus, we suggest that the likelihood of cataract formation increases with increasing protracted exposure to ionising radiation, with no apparent threshold level.…”

Risk of Cataract Incidence in a Cohort of Mayak PA Workers following Chronic Occupational Radiation Exposure

“…ERRs/Gy in the Adult Health Study were 1.3 (95% CIs: 1.1, 1.5) for surgically removed cataracts [ 24 ] and 1.06 (95% CIs: 1.01, 1.11) for total cataracts [ 7 ]. The risk estimated for cataract incidence in the present study was markedly lower than those reported for the cohort of Chernobyl clean-up workers which was 1.6 (95% CIs: 1.2, 2.3) [ 6 ] and found for surgically removed cataracts in the US radiologists which was 2.5 (95% CIs: <1.07, 7.4) [ 25 ].…”

Dose reduction in computed tomography: the effect of eye and testicle shielding on radiation dose measured in patients with beryllium oxide-based optically stimulated luminescence dosimetry

“…Artifacts seem to be of minor importance for orbital shielding [7,9], or may be avoidable if the eye shield is placed properly [11]. Our results and recent data on the substantial radiation sensitivity of the lens [4] support the recommendation for subsequent usage of orbital shielding.…”