Radiation Technologists And Radiologists Have Higher Risk Of Cataract Due To Occupational Radiation Exposure
Source: Thailand Medical News Dec 29, 2019 5 years, 1 day, 22 hours, 47 minutes ago
According to a new study in a large prospective cohort of US
radiation technologists, higher cumulative occupational exposure to low-dose
radiation is associated with excess additive
risk (EAR) of developing
cataract.
Dr. Mark P. Little of the National Cancer Institute in Bethesda, Maryland told
Thailand Medical News, "Our findings, if confirmed, have important implications for clinical screening and public health along with consideration of
radiation protection and regulatory measures, particularly for physicians performing fluoroscopically guided interventional procedures who have been shown to potentially receive
eye-lens doses well over 100 mGy."
Dr. Little and his team note in
Occupational and Environmental Medicine Journal that high doses of
radiation (1 Gy or more) can cause
cataracts, and growing evidence suggests that cumulative lower doses (100-250 mGy) may induce
cataracts as well.
So far, studies of
radiation exposure and
cataract have measured excess relative
risk (ERR), the proportional increase in
risk of exposed vs. unexposed individuals. The authors used excess additive
risk (EAR), which they say can more effectively gauge the public-health impact of
radiation exposure "by providing an estimate of the number of cases that could potentially be prevented by reducing this
exposure."
The medical researchers looked at a cohort of more than 63,352
radiation technologists with more than 832,000 person-years of follow up, including 11,345 with self-reported
cataract. Radiation exposure was strongly associated with
cataract, but not with
cataract surgery.
The cataract
risk associated with
radiation increased with age and was especially high among people 75 and older. Having diabetes was associated with a nearly 20-fold increase in radiogenic EAR.
Dr. Little added, "Our study suggests that about five excess cases of cataract would be expected among 1,000 persons receiving 50 mGy (close to the mean level of exposure of 56 mGy in this cohort) and followed over 10 years (close to the mean 13.1-year follow-up). This suggests that special protective measures may be warranted for persons with diabetes who undergo
radiation exposure."
He concluded, "Future studies should assess EAR of
cataracts along with ERRs in other
radiation-exposed occupational groups with clinically ascertained diagnosis of
cataract by
cataract type, medical record validation of
cataract severity/opa
city, well-validated dosimetry and high-quality data on relevant life-style, environmental and medical risk factors, to ascertain if our findings are confirmed that
cataract is inducible by low doses of
radiation (at <100mGy).”
Reference: Occupational radiation exposure and excess additive risk of cataract incidence in a cohort of US radiologic technologists, Mark P Little, Elizabeth K Cahoon, Cari M Kitahara, Steven L Simon, Nobuyuki Hamada, Martha S Linet, Occupational and Environmental Medicine 2020;77:1-8. , https://dx.doi.org/10.1136/oemed-2019-105902
